The Mercedes-Benz SL-Class sports cars –introduction
- The tradition of these extraordinary sports cars begins in 1952
- The Mercedes-Benz SL-Class has its roots in racing history
- Every SL generation is an innovation platform for the Mercedes-Benz brand
Stuttgart – In the 1950s, a very special star rose in Stuttgart: the Mercedes-Benz SL-Class was born.
It all began with motor racing sports. With its successes in international competitions, in 1952 the 300 SL competition sports car (W 194 series, “SL” stands for “Super-Light”), became the initial spark for the start of two fascinating production sports cars – the “Gullwing” coupé and the roadster: the Mercedes-Benz 300 SL and 190 SL laid the foundation for the tradition of this legendary sports car family in the year 1954.
Mercedes-Benz caused a sensation with the presentation of these two vehicles at the 1954 International Motor Sports Show in New York. Specialists and the general public alike were enthusiastic. The 300 SL was presented for the first time as a series-production sports car (W 198 series), the famous “Gullwing” coupé.
The totally newly-designed 190 SL (W 121 series) presented by the company as a roadster, created just as powerful an impact. This first-generation SL sports cars already allowed one to envisage the brilliant future that lay ahead of these attractive and innovative production vehicles with motor sport abbreviations in their designation.
Based on the legendary Gullwing coupé, the open 300 SL Roadster (W 198 II), which was built in parallel with the 190 SL, was launched in 1957. The body form of the two-seater open car was thus defined as the typical characteristic of the SL family. The 300 SL and the 190 SL together prefigured numerous features of later SL generations and both were thus the forerunners of all the SL series that followed.
In 1963 the SL, W 113 series arrived on the scene; it was dubbed the “Pagoda SL” because of the characteristic shape of its hardtop roof. It was followed in 1971 by the R 107 series that achieved the highest production volume of all SL series to date because of its long production life of 18 years.
In March 1989 Mercedes-Benz introduced the R 129 series. Featuring numerous technical innovations, this car carried the SL-Class over into the new millennium. After a production period of twelve years and two facelifts it was replaced in 2001 by the R 230 series – the first one with a steel folding top. Finally, in the spring of 2012 the R 231 series is due to be launched as the next generation of the Mercedes-Benz SL-Class.
From racing car to SL-Class with vario-roof – a summary
- Motor sport as initial fuse
- Numerous fascinating models from 1952 until today
Mercedes-Benz 300 SL racing car, W 194 series (1952 to 1953)
The roots of the SL-Class lay in motor sports: after World War II Mercedes-Benz developed the W 194 series 300 SL racing car, whose M 194 engine was derived from the 300 model; engineers increased its output to around 170 bhp (125 kW) for use in the racing sports car. The sports engine was installed at an angle of 50 degrees slanted over towards the left.
For the W 194, Rudolf Uhlenhaut, at that time Head of Passenger Car Research at Daimler-Benz, developed a frame weighing only 50 kilograms and made from very thin tubing that was subjected to compressive and tensile forces only. This frame became the backbone of the racing car with which the pilots of the racing department reaped numerous victories in 1952.
The body of this first SL already prefigured features of the later production sports car. Among these, the wide, low racing car front end of the pre-war era, with a Mercedes star affixed to the radiator grille. Characteristic for the coupé: the famous swing-wing doors, deeply incut into the roof.
To open, they swung upwards, reminding one of outspread wings, for this the Americans dubbed it the “Gull-wing”, while the French called it the “Papillon” (butterfly). Together with the coupés, several roadsters were also made.
With the 300 SL, Mercedes-Benz won second and fourth places at the Mille Miglia race, achieved a three-fold victory at the sports car race in Bern and a double win at the 24 hours of Le Mans, as well as four victories at the Nürburgring sports car race in 1952.
The last great adventure of the season was its participation in the 3rd Carrera Panamericana in Mexico, with a gruelling route covering 3100 km in five days and eight stages.
Mercedes-Benz entered two coupés and two roadsters in the contest; these were powered by engines with an output that had in the meantime been increased to 180 bhp (132 kW). Karl Kling and Hans Klenk’s car, as well as Hermann Lang and Erwin Grupp’s car, attained a legendary double victory for Mercedes-Benz in November 1952.
Already for the following year a successor model was developed, the W 194/11; however, it did not get to participate in the 1953 racing season because from 1954 Mercedes-Benz began to take part in Formula 1 racing, so that from the 300 SL the W 198 I series sports car was developed
Mercedes-Benz 300 SL Coupé, W 198 I series (1954 to 1957)
It was to be the perfect suprise: on 6 February 1954, Mercedes-Benz presented the 300 SL series sports car at the International Motor Sports Show in New York. The coupé with the characteristic swing-wing doors of the racing car fascinated experts and general public alike.
Not only its form was reminiscent of motor sports, technical details, too, such as the tubular space frame, came directly from the competition cars. This made the 300 SL, W 198 I series, unique among the sports cars of its day.
The production SL was powered by an M 198 engine with petrol direct injection, developed by Mercedes-Benz for the W 194/11 racing car prototype of 1953. In the 300 SL, the 6-cylinder in-line engine had a nominal output of 215 bhp (158 kW), which enabled the car to reach a top speed of 247.5 km/h, as stated in 1954 after an official test drive.
For a comfortable street sports car of those days an excellent value indeed. That predestined the 300 SL for use in racing competitions and rallies, where factory drivers and private pilots were able to win numerous victories and excellent placings with it.
Maximilian E. Hoffman, the official importer of the Mercedes-Benz brand in the US, campaigned tirelessly for the series production of the sports car. At the same time he urged the production of a smaller SL roadster, which was later to be the SL Roadster, 190 series.
The 300 SL rapidly became an automotive icon of the 1950s, while it was victorious on many racetracks at the same time. And its charisma remains unbroken to this very day: in 1999 the Gullwing coupé was voted “Sports car of the century” in an international election.
Mercedes-Benz 190 SL, W 121 series (1955 to 1963)
Daimler-Benz AG introduced the Mercedes-Benz 190 SL together with the 300 SL in February 1954 at the International Motor Sport Show in New York. It was designed as a sports car “which owing to its high comfort is intended for a class of customers who want to travel large distances themselves at high cruising speeds in this externally very sporty looking car,” as design engineer Josef Müller wrote in retrospect in 1957.
Simultaneously the Mercedes-Benz 300 SL “Gullwing” debuted in New York. As an exciting super sports car it too lent the SL series its character.
The body design of the 190 SL closely followed that of the Gullwing, but it was constructed as a two-seater cabriolet and had a retractable soft top. A nice option to be had was the third-passenger transversal seat. There were three versions: a car with a fabric top and a coupé with removable hardtop, optionally with or without a fabric top.
The 190 SL was given the internal series designation W 121, like the 190 Saloon that appeared a little later in 1956. The 190 SL is technically related to the “Ponton” (pontoon) saloons – commonly called that because of their characteristic body shape – of the W 120/121 series.
The suspension, for example, from model 190 (W 121) onwards featured the familiar low-pivot single-joint swing axle and the front wheel suspension including subframe. The floor assembly – albeit shortened – was also taken from the saloon.
The 1.9-litre petrol engine, on the other hand, was an entirely new development. This four-cylinder unit had an overhead camshaft and is regarded as the forefather of an entire family of engines. In the Mercedes-Benz 190 SL it delivered 105 bhp (77 kW) and accelerated the fabric-topped variant from 0 to 100 km/h in 14.5 seconds on its way to its top speed of 170 km/h.
During its production life the 190 SL underwent many improvements in details. The last unit was built in 1963 at the Sindelfingen plant, ending a production run totalling 25,881 vehicles.
Mercedes-Benz 300 SL Roadster, W 198 II series (1957 to 1963)
In 1957, the Gullwing coupé was superseded by the 300 SL Roadster. Like its predecessor, this vehicle, too, was created upon the initiative of Maximilian E. Hoffman. Technically, the roadster was basically the same as the coupé, but through modification of the side sectors of the tubular space frame, it was made possible to reduce the entry height enough to allow the fitting of conventional doors.
A fundamental improvement: the rear-axle suspension. The single-joint low-pivot swing axle – familiar from the 220 W was installed in the 300 SL Roadster in an adapted form, being equipped for the first time with a compensating spring.
This greatly improved the handling characteristics over those of the original swing axle of the Gullwing coupé. From 1958 onwards, an optional removable coupé roof with a generous wrap-around rear window was available.
At this time there was a special version of the 300 SL Roadster: the 300 SLS, only two units of which were ever built especially for participation in the North American Sports Car Championship. At the wheel of this car, Paul O’Shea won the 1957 North American Sports Car Championship in the D category far ahead of competitors.
Production of the 300 SL ended together with the end of production of the 190 SL in Sindelfingen on 8 February 1963. Both versions of the 300 SL, the roadster and the Gullwing coupé were enthusiasts’ cars from the very start and are today among the most sought-after and most valuable classic cars.
Mercedes-Benz W 113 series (1963 to 1971)
At the 1963 Geneva Motor Show, Mercedes-Benz presented the new 230 SL – internal series designation W 113. It was designed as a comfortable high-performance two-seater touring car and replaced the 190 SL and 300 SL models. Three versions were available: an open-top car with a folding soft top, an open-top version with hardtop, and finally the hardtop coupé.
The hardtop coupé had no soft top and soft-top compartment; this freed up more room for luggage. All three versions could be driven with the top open. As an optional extra a transverse rear seat was available.
The exterior of the 230 SL was characterised by clear, straight lines and the unmistakable SL face including the large, centrally positioned Mercedes three-pointed star. The hardtop with high windows and a roof borne up only by slim pillars conveyed an impression of lightness; with its inwardly directed curvature it reminded one of Far Eastern temples, and straightaway the car had a nickname: “Pagoda”.
Since it was based on the floor unit of the famed “Tailfin”, the world’s first saloon with a safety body, this SL also had a rigid passenger cell and crumple zones in the form of easily-deformable front and rear segments. As in the saloon the interior was designed so as to reduce injury hazards in accidents, meaning that there were no hard corners and edges.
As in the previous model, seat belts were available as optional extras. The steering gear was moved from the crash-imperilled front section to the firewall; the steering column yielded to axial compression and additionally featured a joint that prevented the feared lance effect in an accident. In 1967, the telescoping safety steering column and the impact absorber in the steering wheel were added.
The chassis, adopted from the 220 SE Saloon, was tuned to the requirements of the sporty car. The suspension was taut, but for a sports car was almost atypically comfortable. The six-cylinder engine also came from the saloon, but was modified for use in the SL. The engine, its bore enlarged to give it a displacement of 2.3 litres, developed 150 bhp (110 kW) and was designed as a sporty drive unit.
The successor to the 230 SL came in 1967: the Mercedes-Benz 250 SL. The changes mainly concerned the engine and the braking system. The engine, its displacement enlarged by 200 cubic centimetres, had the same output, 150 bhp (110 kW), but ten per cent more torque. The 250 SL was thus appreciably more flexible in its response.
In addition to the three body versions known from the 230 SL, the 250 SL was available as an optional extra in a fourth version, a coupé with rear bench seat, shown for the first time in March 1967 at the Geneva Motor Show. Less than a year after the presentation of the 250 SL, it was replaced by the 280 SL with a 2.8-litre engine and an output of 170 bhp (125 kW). From 1963 to 1971 a total of 48,912 “Pagodas” were built – remarkable for a sports car with such high standards.
Mercedes-Benz R 107 series (1971 to 1989)
The R 107-series SL rolled out on the highway in spring 1971, first as 350 SL (147 kW/200 bhp), from autumn 1971 onwards and at first only for the US, as series 350 SL 4.5, and then with the Geneva Motor Show from 1973 onwards for all markets as series 450 SL (165 kW/225 bhp). For the first time in the history of the SL series an eight-cylinder power plant did duty under the bonnet.
Parallel to it the corresponding coupé models of the SLC series (C 107 series) were built until autumn 1981.
Besides elegance and quality the vehicles radiated safety: the crash response of the open two-seater was far ahead of its time. Technically, this expressed itself in a carefully-defined crumple behaviour of coachwork and vehicle skeleton structure, a high-strength A-pillar, and interior appointments uncompromisingly designed according to safety criteria.
In the course of its production “lifetime” of unplanned length (18 years) and immense success, this SL was equipped with diverse six- and eight-cylinder engines. Its model designations were accordingly just as varied. In July 1974 came the 280 SL (136 kW/185 bhp), with the result that there were now three SL engines available to choose from – nowadays nothing unusual, but in those days something a real novelty in the history of this model category.
In the course of time all engines underwent modifications (and slightly modified performance figures) to enable better compliance with the emission standards, which had meanwhile started to become more stringent in most European countries.
Production of the R 107 series ended in August 1989, more than 18 years after the production start-up of the 350 SL. With that this SL series set an internal record that will probably never be broken: with the exception of the G-Class off-road vehicles, no other passenger car series has ever been produced over such a long period in the entire history of the company.
All told, in Sindelfingen 237,287 open-top cars were built, a number which impressively demonstrates the great popularity of the 107 series. Of the coupé a total of 62,888 were built from 1971 to 1981.
Mercedes-Benz R 129 series (1989 to 2001)
At the 1989 Geneva Motor Show, Mercedes-Benz presented the SL, R 129 series. The first models were the 300 SL (140 kW/190 bhp), 300 SL-24 (170 kW/231 bhp) and 500 SL (240 kW/326 bhp).
The stylistically assured, no-frills lines of the slightly wedge-shaped body, the flared wheel arches, the half-spoilers forward of the front wheels, a steeply raked windscreen, the skilfully modelled rear end and the standard light-alloy wheels produced an exceedingly harmonious overall effect.
The brand scored a hit with the vehicle. Production capacity was soon stretched to the limit and delivery periods of several years had to be accepted.
This car set new standards in the area of safety. The results of Mercedes-Benz’s rigorous frontal and rear-impact crash tests for the open-top vehicle were sensational. Integral parts of the safety concept were also the automatic roll-over bar, which popped up, sensor-controlled, within 0.3 seconds when a roll-over threatened, and the integral seats, whose resistance in a crash was many times higher than the magnitude of the forces that could be expected.
The suspension was adapted to the requirements of a touring sports car and enabled precise handling and fast driving combined with high comfort. In autumn 1992, a further model appeared, the 600 SL with a twelve-cylinder engine and an output of 290 kW (394 bhp).
A first facelift in autumn 1995 brought a slightly modified body design, more extensive standard equipment, and more refined engineering. A second facelift in 1998 employed discreet stylistic touch-ups to give the sports car an even more dynamic look, but mainly meant a change in the engine range, with new six-cylinder V-engines in place of the previous in-line engines, and a new V8 power plant
In summer 2001, production of the R 129 series came to an end after twelve years and a total of 204,940 units. In terms of overall volume it was not quite as successful as its predecessor from the R 107 series (237,287 units); but if average annual production is compared, the R 129 series with some 16,500 units takes a very clear lead.
Mercedes-Benz R 230 series (2001 to 2012)
The most conspicuous innovation in the subsequent SL generation with the internal designation R 230 was the vario-roof: for the first time in the history of the SL it was made possible to have an open-top car and a coupé in one – the transformation took place within 16 seconds.
The first model presented to the public in summer 2001 was the SL 500 (225 kW/306 bhp); in the autumn it was joined by the SL 55 AMG (350 kW/476 bhp). In 2002 the SL 350 (180 kW/245 bhp) followed, in 2003 the SL 600 (386 kW/500 bhp) and in 2004 the SL 65 AMG (450 kW/612 bhp).
The design of the R 230 series blended tradition and future through distinctive details. For instance, the air intakes in the front wings adopted a typical feature of the 300 SL from the 1950s. The thin, wing-like segments on these side air intakes – called fins by experts – were a reminiscence, too.
Ever since the “Pagoda” at the latest, the abbreviation SL has been synonymous with pioneering achievements in the areas of active and passive safety in open-top sports cars. With an entirely new, comprehensive concept the R 230-series SL clearly outstripped all previous safety standards.
The concept included electronic handling dynamics systems such as SBC™ Sensotronic Brake Control, ABC Active Body Control, BAS Brake Assist, ASR acceleration skid control, and ESP® and extended to the structural integrity of the body in every conceivable type of accident.
A number of other features contributing to occupant protection were two-stage airbags for driver and passenger, head/thorax bags in the doors, integral seats, high-performance belt tensioners, belt force limiters, and the sensor-controlled roll-over bar, which goes into action even when the vario-roof is closed.
The first facelift came in 2006. It brought the SL 500 a 285 kW (387 bhp) V8 engine and the SL 350 a 200 kW (272 bhp) V6 engine – both new developments featuring four valves and reduced fuel consumption coupled with a higher output; in the SL 600 it was now 380 kW (517 bhp).
The 7G-TRONIC seven-speed automatic transmission was standard equipment. The most conspicuous element of a further model refinement package in 2008 was the new front design, which adapted the SL to the brand’s current passenger car design. In addition, the SL 280 (170 kW/231 bhp) was added to the model range. In 2008, the exclusive SL 65 AMG Black Series expanded the R 230 series in the top performance range.
This high-performance coupé was developed in the AMG Performance Studio, and was powered by an engine delivering 493 kW (670 bhp).
In 2008 and 2009, the SL 63 AMG Roadster went into action as Official F1™ Safety Car in Formula 1 racing. The SL, modified for operation on the racetrack, brought to mind the roots of the SL family in motor racing.
In the spring of 2012, Mercedes-Benz is to unveil the R 231 series, the new SL.
Motor sports as initial fuse: the Mercedes-Benz 300 SL racing sports car, W 194 series (1952-1953)
- The first racing car from Mercedes-Benz after the Second World War
- Combination of series-production technology and innovative lightweight build
- Racing as a coupé and as a roadster
- 1953 racing sports car prototype shows elements of the production sports car
Mercedes-Benz 300 SL was the designation of the competition race car from Mercedes-Benz with which the brand returned to international motor sports in 1952 for the first time after the Second World War. And although this car was not sold to the public, it did light the fuse for the development of the later SL-Class from Mercedes-Benz.
The development of the 300 SL began in 1950, when Mercedes-Benz began to think about a return to racing. The attempt to reactivate the 1939 W 154 Grand Prix race car, however, met with failure in Argentina in 1951. So engineers pressed forward the development of the new racing car, some of the components of which came from the Mercedes-Benz 300.
In June 1951, the Board decided to resume participation in racing events from 1952 on, and gave the final orders for the construction of the 300 SL. The abbreviation was explained as “Super-Light”. Its M 194 engine was derived from the 300 type unit, the M 186, with an inclined separation plane between cylinder-head and engine block, overhead camshaft, large inlet valves, combustion chamber in engine block and pistons, a displacement of 3 litres and an output of 115 bhp (85 kW).
For its use in the racing car the engineers increased the engine’s output to around 170 bhp (125 kW). The sports engine differed from the one installed in the saloon and coupé not only in its output, but also in its installation position, slanted 50 degrees to the left, and in having a dry-sump lubrication system, which due to the omission of the oil sump, enabled a lower installation height.
Weight savings were hardly possible with the engine and the transmission of the W 194 that was in the process of being created. And this was also true of the heavy steel axles which had also been taken from the 300 model. That left only the frame and the exterior skin for any possible weight-savings.
Another possibility for enhancing competitiveness was to create a body as aerodynamic as possible. Rudolf Uhlenhaut, at that time Head of passenger car research at Daimler-Benz, took up his idea of a lightweight tubular frame again, an idea he had entertained some years before.
The designers then carried the concept forward to its logical conclusion, creating a lightweight, extremely torsionally rigid frame consisting of very thin tubes joined together to form triangles, whose tubular elements were only subjected to tensional and compressive forces.
The entire frame weighed just 50 kilograms and became the backbone of the W 194, as well as the basis for the production version of the 300 SL (W 198 I) and for the successful 1954/55 racing and motor sports car.
The coachbuilders in Untertürkheim and Sindelfingen spared no effort with the vehicle aluminium body. Thanks to the canted position of the engine and the aerodynamic profile they strove to create, the car was very low, free of trim right down to the underbody, with an elegant low bonnet line, intuitively round-shaped, with recessed headlamps and its wheels entirely covered by the bodywork.
The classic Mercedes-Benz radiator shape was replaced by a flat racing car front end analogous to that of pre-war cars.
The Mercedes star dominated the radiator grille prominently. The coupé geenhouse was made as narrow as possible, with a strongly raked windscreen, curving towards the A-pillars. The large rear window flowed over into the aerodynamic rear end. The result was a relatively small frontal area: 1.8 square metres. A drag coefficient was measured on an 1-in-5 scale model and found to be
cd = 0.25, and that, even without taking into account the realistic airflow through the engine compartment.
The doors are a chapter all of their own: in order to lend a space frame the desired high rigidity, it has to be as wide as possible in the passenger cell sector. This requirement led to the spectacular and later so famous gullwing doors. In the first cars, the door opening began at the waistline.
The doors, deeply incut into the roof, opened upwards, creating an image reminiscent of outspread wings, for which reason the car was dubbed “gullwing” by the North Americans and “papillon” (butterfly) by the French. Driver and passenger boarded the car from above.
In order to facilitate access over the high side sill, the bodywork designers had even originally intended to have an access step in the lower part of the vehicle body flank; however, this feature was never realised. By the way, the FIA regulations of the time did not specify the type and direction of opening doors.
In spite of this, the stewards got a bit hot under the collar when the vehicle was presented to them for scrutineering before the Mille Miglia in May 1952. To forestall any future protests, after the race in Italy the doors were extended down into the car’s sides, thereby assuming their final shape.
The interior was fully padded and lined, radiating a level of comfort unusual for racing cars. Speedometer and rev counter were accomodated under a common hood, below that and in somewhat smaller format were the gauges for water temperature, fuel pressure, oil temperature and oil pressure.
Even a stopwatch was installed. The bucket-type seats with high side sections were covered with tartan-style woolen fabric; the four-spoke steering wheel was removable to facilitate climbing in.
The archetype of the 300 SL, chassis number W 194 010 00001/52, completed its first test drives in November 1951, on the Solitude racetrack just outside Stuttgart, on the Nürburgring and on the Hockenheimring. On March 12, 1952, the Mercedes-Benz 300 SL racing sports coupé, unusually smooth and, at a height of just 1,225 millimeters, unusually low, was presented to the excited and stunned press on the motorway between Stuttgart and Heilbronn.
A total of ten W 194 series cars were built for the 1952 season. After the Le Mans race, it was planned to enter the SL in a sports car race on the Nürburgring. To shed as much weight from the competing cars, the engineers cut the roofs off three coupés without further ado.
A fourth car had been set up as a roadster right from the start. To permit easy access, the section of the door extending into the side of the car was retained, and a small windscreen was mounted to deflect air and flying insects. This resulted in a weight advantage of 100 kilograms over the coupé.
The year 1952 was an extremely successful one for Mercedes-Benz racing cars: second and fourth places in the Mille Miglia; triple victory in the sports car race in Bern; double victory at the 24 Hours of Le Mans; quadruple victory in the sports car race on the Nürburgring.
The last big adventure of the season was participation in the third Carrera Panamericana Mexico, a race over five days and eight stages, 3,100 kilometres through Mexico. Mercedes-Benz accepted the challenge and entered two coupés and two roadsters in this rally, all powered by engines with an output meanwhile boosted to 180 bhp (132 kW).
Karl Kling with Hans Klenk and Hermann Lang with Erwin Grupp reaped a legendary double victory for Mercedes-Benz in November 1952 in this contest.
The 300 SL was reengineered for the 1953 season. Its bodywork was now made from magnesium sheet, even lighter than aluminium. In the wind tunnel it gained – especially in its front section – not only a new face, but also a better airflow through the engine compartment thanks to an optimised shape.
The engine output rose, too, among other things thanks to petrol direct injection, which boosted output of the six-cylinder unit to 215 bhp (158 kW). The rear axle was further developed to a low-pivot single-joint swing axle, while the transmission was flanged on the rear axle following the transaxle principle, which made for a more balanced weight distribution.
The wheelbase was shortened by 100 millimetres. The vehicle stood firmly on 16-inch wheels, and the use of disc brakes was considered.
This further-developed 300 SL with the company-internal designation W 194 (jocularly called “carpenter’s plane” on account of its front end), did not actually get to race. However, its bodywork with its angular radiator, compact dimensions and ventilation fins as well as its engine, prefigured in 1953 the W 198 I series 300 SL production sports car that was unveiled the following year.
Technical highlights of the Mercedes-Benz 300 SL (W 194)
300 SL racing sports car (1952):
- Lightweight tubular space frame
- Coupés designed with roof-hinged Gullwing doors
- Racing sports car prototype 300 SL, W 194/11 (1953)
- Six-cylinder in-line M 198 engine with petrol direct injection
- Vehicle body made from magnesium sheets
Production figures for MB 300 SL (W 194) Roadster, Coupé, racing sports car prototype
|Models||Internal designation||Production period: |
pre-production to end
|Number of units|
|300 SL300 SL racing sports prototype||W 194W 194/11||19521953||101|
The “Gullwing” enters the scene: Mercedes-Benz 300 SL Coupé, W 198 I series (1954-1957)
- Breathtaking sports car with racing sport genes
- The Gullwing coupé fascinates experts and public
- Maximilian E. Hoffman campaigns for a production SL
It was to be the perfect surprise: the 300 SL production sports car Mercedes-Benz presented at the International Motor Sports Show in New York on 6 Februar 1954 was a sensation. At its world première, the coupé with its characteristic gullwing doors made the hearts of experten and public skip a beat.
Technical details such as its space frame and its extraordinary door design were without parangon among the sports cars of its day.
The bodywork with its flat, long bonnet and distinctive splash guards above the wheel arches, featured many elements of the W 194/11 prototype from 1953, for instance the typical powerdomes. And the family likeness extended to the area below the bonnet, too, for the W 198 I adopted the fuel direct injection of the prototype.
In the 300 SL the 6-cylinder in-line engine had a nominal output of 215 bhp (158 kW) enabling a top speed of 260 km/h according to the relevant brochure. This value was calculated for an engine speed of 6500 rpm and a rear axle ratio of 1:3.25.
In actual fact, though, the vehicle did not quite reach this value: on an official test drive carried out by the factory in August 1954 it reached a maximum speed of 247.5 km/h, averaged between outward and return legs, the best speed in one direction was 252 km/h. However: for a cultivated road-going sports car of the time these were outstanding values.
This exceptional driving performance was matched by an exceptional price, because in 1954 29,000 Marks was a fortune. The 190 SL Roadster, unveiled together with the 300 SL, cost 16,500 Marks, placing it in the upper price segment, too.
For comparison: at that time a Mercedes-Benz 200 (W 180) luxury saloon with a six-cylinder in-line engine could be acquired for around 12,500 Marks. In the summer of 1954 production of the 300 SL started up. The production vehicle possessed a series of detail improvements, including a greater level of comfort, over the exhibition car.
It was only natural for the 300 SL to have its world première in New York, for it was Maximilian E. Hoffman – since January 1952 official importer for the Mercedes-Benz brand for the US market – who campaigned intensely for the construction of a production sports car.
Apart from the series 180 and 300 Saloons, he was particularly interested in the 300 SL (W 194) racing sports car, whose great successes boosted the popularity of the Mercedes-Benz brand in the United States explosively. Hoffman saw assured sales prospects for a production version of the car. At the same time he broached the idea of a smaller SL roadster based on Type 180 – this was how the 190 SL came to be.
Daimler-Benz was fully taken up with design and development tasks, so that the Stuttgart-based company even cancelled its originally planned participation in sports car races in 1953. Because of this, Hoffman’s demand for a 300 SL Sports Coupé was not exactly opportune, although it did have a certain attractiveness of its own, for a true sports car was still missing in Mercedes-Benz’s portfolio.
However, there were only a few months left before the New York Auto Show, which would be an excellent opportunity for the presentation of the new Mercedes-Benz passenger car programme. This lead the Board of Director to decide to turn the 300 SL racing car prototype developed for the 1953 season into a road-going version suitable for everyday use.
After the first tests, the press was beside itself. The German trade journal “auto, motor und sport” wrote: “Among the sports cars of our time, the Mercedes-Benz 300 SL is both the most refined and the most fascinating – a dream of a car.
” The British journal “AutoSport” enthused: “The Mercedes-Benz 300 SL is a car with a wonderful external appearance, coupled with virtually unbelievable performance. Its design and production quality border on perfection and the entire concept represents the uncompromising realisation of all the new ideas the car incorporates.”
The hope of success in the United States market also became reality: the US journal Road & Track was equally full of praise: “When a comfortable interior combines with remarkably good handling, with almost terrifying road-holding, a light and at the same time precise steering and a performance that matches or even exceeds that of the best cars to date, then there’s only one more thing to say: The sports car of the future has become reality.”
The racing heritage of the 300 SL seduced renowned racing pilots and private drivers all over the world into entering the car in sports car races and rallies. In the 1955 Mille Miglia, the team of John Cooper Fitch and his co-pilot Kurt Gesell drove a production SL to superior victory in their category.
Werner Engel won the European touring car championship in an SL in 1955, Walter Schock in 1956. The Liège–Rome–Liège marathon rally was won by Olivier Gendebien in 1955 and by Willy Mairesse in 1956. In the USA, Paul O’Shea clinched the American Sports Car Champion’s title in Production Class D of the championship series organised by the Sports Car Club of America in 1955 and 1956.
A total of 30 series W 198 I vehicles with aluminium lightweight bodywork were made in 1955 and 1956. They bore their own specific vehicle identification numbers, except the first car of the series, which was given a steel sheet bodywork vehicle identification number.
This aluminium version, 130 kilos lighter than the standard version, was not listed in the price lists but could be ordered just like a regular car. Customers with motor sport aspirations were among the main target groups for this lighter gullwing car.
A further rarity was a coupé with a glass-fibre-reinforced bodywork.
This unique specimen, today the property of the company’s own
vehicle collection, can be identified by two details: on the front wings it sports two headlamps with long chrome strips such as those on the 220 a and 220 S. And the doors do not close as tightly as those of its steel sheet or aluminium sheet counterparts.
The road-going racing coupé became the symbol of success for the rich and the beautiful of its day and age, a dream come true for a few other people and for many a dream they were at least able to see and hear every now and then.
The engine’s vibrant melody fascinated people just as much as the elegance of the ladies who managed to slide into the depths of the seat and emerge again in well-practiced, perfectly lady-like fashion. By 1957, 1400 customers all over the world had taken delivery of 300 SL Coupés.
Very soon the W 198 I became a much-sought-after classic; over the following decades, well-maintained cars continued to fetch astronomical prices. The timeless elegance which the Gullwing coupé radiates to this very day was honoured in 1999 when it was voted “Sports Car of the Century” by an international jury.
Technical highlights of the Mercedes-Benz 300 SL (W 198 I)
- Lightweight tubular spaceframe
- Coupé with roof-hinged gullwing doors
|Production period: |
pre-production to end
|Number of units|
|300 SL Coupé||W 198 I||1954-1957||1,400*|
* 30 of which with light-metal bodywork, the first vehicle bearing a steel sheet metal bodywork vehicle identification number.
Appealing and comfortable: Mercedes-Benz 190 SL Roadster, W 121 series, (1955-1963)
- The first open-top production sports car of the SL family
- A sporty-elegant two seater road-going motor car
- The USA, an important market for the vehicle
- Première for a new four-cylinder engine with a displacement of 1.9 litres
An elegant, open-top sports car with the Mercedes star on its radiator: That is model 190 SL (W 121), which Mercedes-Benz presented in New York in 1954 and whose market launch was in 1955. The roadster’s story began with Maximilian E. Hoffman, since 1952 the New York-based official Mercedes-Benz importer for the US market.
In 1953 he realised the sales potential for sports cars from Mercedes-Benz in the USA, and then campaigned for two of these vehicles to be built as production vehicles: according to Hoffman’s recommendation, the 300 SL Racing Coupé (series W 194) was to be made available – with modifications – as a production vehicle, and the Stuttgart-based brand was at the same time to produce an open-top sports car to accompany the Gullwing coupé. That is how the 190 SL was born.
At the time Daimler-Benz was fully saturated with design and development tasks – both for production vehicles and also with the preparation for the 1954 racing season, for which the new W 196 R series formula racing car was intended. Due to the enormous workload, the Stuttgart-based company even stalled their planned participation in the 1953 sports car races.
The new SLs increased the pressure, but were considered important for Mercedes-Benz’s image and market position. For the 1950s were a time of great expansion after the Second World War. With sports cars Mercedes-Benz would be able to round off its model range with attractive, exclusive vehicles in a new segment – ever since 1935 decidedly sporty cars had been missing in their portfolio.
Thus already in mid-September of 1953 the Board’s decision was taken: the 190 SL and the 300 SL were to be built as series production cars.
About five months later both cars were to celebrate their premières in America: they were presented at the International Motor Sports Show in New York which took place there from 6 to 14 February 1954, at that time the most important motor show on the other side of the Atlantic. This meant that the engineers had very little time for development.
Speed was of the essence, especially in the case of the 190 SL, which had to be technically redesigned based on the 180 series, whereas for the 300 SL production sports car, the further-developed 300 SL racing sports car served as a model. Already a few days after the Board’s decision, the directors of Daimler-Benz were examining the first sketches, and two weeks further on they were able to assess the first 1:10 scale model, which was followed another eight weeks later by a full-scale model.
The pace of development was raised still further. The floor assembly, which came from the Mercedes-Benz 180, had to be adapted to the new ideas and the right engine had to be found. Moreover, the tight schedule stipulated that the contours of the planers on which the body would be created be finalised by 31 October 1953. The race against time was won: Mercedes-Benz registered a tremendously favourable response to both vehicles at the show.
Until then, the bodies of various models had been available in the two-seater A-version as Cabriolet, Roadster, or Coupé, too. According to chief engineer Fritz Nallinger, this body variant would be replaced in future by the SL vehicles – no longer with the existing formal lines and face, but explicitly in the SL design, which included the star placed centrally on the radiator grille.
This was a paradigm change in the model structure, making the 190 SL and 300 SL the symbols of a new product philosophy and the forerunners of the later SL-Class.
While series production of the Mercedes-Benz 300 SL began in August 1954 at the Sindelfingen plant, the 190 SL was thoroughly revised once more because the car displayed at the International Motor Sports Show in New York was neither technically tested nor stylistically mature. In March 1955, Daimler-Benz then presented the final model of the sports car at the Geneva Motor Show.
The body was designed by Walter Häcker and closely followed the design of the 300 SL Gullwing Coupé. However, unlike the 300 SL, the 190 SL had a retractable soft top.
The production body showed some clear differences from the show car: the stylised intake scoop on the bonnet was dropped; the forward edge of the bonnet had been moved farther back; there were splash guards above the rear wheel arches too; and the bumpers, indicators and tail lights were modified. The Sindelfingen factory started building the pre-production series in January 1955. Main series production commenced in May.
The 190 SL is technically related to the “Ponton” (pontoon) saloons – commonly so called because of their characteristic body shape – of the W 120/121 series. Their internal designation was W 121, and the 190 that appeared in 1956 was also given that designation. From the beginning the 190 SL was designed as a two-seater cabriolet.
In the 1950s, the meaning of the term “roadster” experienced a change. The classic roadster was a rather spartanly equipped sporty two-seater with detachable side windows, for instance, and a removable fabric top with its roof frame. But the customers’ comfort standards were now higher, and the Mercedes-Benz 190 SL sports car responded to this. Though not a roadster in the classic sense, it was designated as such by the company.
In contrast to the 300 SL, bearing the mark of its racing sport origins, it was conceived as a sporty-elegant two-seater touring and utility car. It was available in three versions: as a car with a fabric top (price in February 1955: DM 16,500) and as a coupé with removable hard top, optionally with or without a fabric top (price in September 1955: DM 17,650/DM 17,100).
These prices make clear the exclusive placing of these vehicles in the model range. The 300 SL cost DM 29,000 DM in 1954, and thus considerably more than the 190 SL, however, the sports car was clearly placed above the Saloon – thus Mercedes-Benz offered model 180 at a list price of DM 9450 in 1954/1955. As an optional extra, a third, transversal seat could be fitted in the rear of the 190 SL.
The motor press praised the 190 SL among other things for its safe handling properties. These were ensured by the low-pivot single-joint swing axle already familiar from the 220 a, and other features. The front wheel suspension including the sub-frame was adopted from model 180, from which the floor assembly – though shortened – also came.
A new development was the 1.9-litre petrol engine with the designation M 121 B II. The four-cylinder unit had a single overhead camshaft and is regarded as the forerunner of an entire family of engines. In the Mercedes-Benz 190 SL it developed 105 bhp (77 kW) at 5700 rpm and accelerated the fabric-topped variant from 0 to 100 km/h in 14.5 seconds.
The top speed was a respectable 170 km/h – which made it one of the fastest cars on the road in the 1950s and 1960s. The petrol consumption was put at a rather moderate 8.6 litres per 100 km; the 65-litre tank provided adequate range.
During its production run the 190 SL underwent many improvements in details. Clearly recognisable are the wide chrome strips on the upper edge of the door (introduced in March 1956) and larger tail lights (June 1956, as also used on models 220 a, 219 and 220 S). In July 1957, the rear licence plate lamp was moved to the bumper horns to enable fitting the wide licence plates which were being introduced at the time.
The rear bumper horns were thus a basic equipment item, while at the front they cost extra; the US versions always had them at the front and the rear as standard. From October 1959, a new hardtop with a larger rear window gave the coupés much improved rear visibility.
In August 1960, the lock of the boot lid was changed; simultaneously a recessed handle replaced the previous bow-type handle. In 1963, the last Mercedes-Benz 190 SL rolled out of the production bay. In all, 25,881 were built. Most of them went to the USA – Maximilian E. Hoffman’s evaluation proved right.
A sports variant of the Mercedes-Benz 190 SL
The first sales brochures showed a sports variant of the 190 SL: light-alloy doors, small Perspex racing windscreen, no soft top, no bumpers, heat exchanger or insulating material, gave it a weight of 1000 kilograms, around ten per cent less than the normal road version.
The number of units built is not documented, and only very few sports versions found their way to the customers; they probably also came in for further fine tuning with modifications to the four-cylinder engine, lowering of the body, sports shock absorbers and modified springs.
The sports 190 SL scored its biggest success in 1956 in the Sports Car Grand Prix in Portuguese Mação, entered by the then Daimler-Benz importer in Hong Kong. The right-hand-drive sports car took first place ahead of a Ferrari Mondial and various Jaguar and Austin-Healey cars. In the same year the Mercedes-Benz general importer in Morocco won his class (GT to two litres displacement) in the Grand Prix of Casablanca.
On account of the racing regulations the idea of the sports 190 SL was not pursued any further: in many competitions the vehicle, modified as described, would have been classed as a production sports car and thus would not have had a chance.
On top of that a decision of the racing authority FIA (Fédération Internationale de l’Automobile) prevented classification as a GT – it said that a Gran Turismo must have a completely enclosable body – a condition which the converted 190 SL could not meet.
The Mercedes-Benz 190 SL in the press
Shortly after the presentation of the Mercedes-Benz 190 SL at the International Motor Sports Show in New York, “auto motor und sport”, Germany, No. 3, 1954, wrote: “The Mercedes 190 SL is an elegant and fast touring sports car that can be used as an ordinary, workaday vehicle, but additionally offers the possibility of successfully competing in smaller sporting events. …
For this new model Mercedes dispensed with its hallowed radiator tradition, as it did for the 300 SL. The very harmonious front end nevertheless shows that elegant and distinguished lines are entirely possible without neglecting the attributes of fashion and functionality.”
The Swiss journal “Automobil Revue”, wrote in its November 14. 1956 issue: “Despite its high output the 190 SL is not actually a sports car, but an uncomplicated touring car that stands with all its four wheels firmly planted on the ground.
Thanks to its exemplary handling characteristics it is among the select group of vehicles with which it is possible to reach the highest average speeds safely and without haste, and taking full consideration of all other road users.”
In its spring issue 21/1957, the German magazine “Motor-Revue” published a first road test report. The tester wrote: “When using the prescribed tyres it is possible to accelerate the 300 SL Roadster with turned front wheels at curve limit speeds, without it showing the slightest tendency to break out.
This meek character of a sports car with top speeds of 235-250 km/h (depending on transmision ratio) with a powerful acceleration capacity, basically due to soft suspension and exceptional adjustment, make the new Roadster the vehicle with the greatest performance and safest handling that I have ever driven.
It seems to me most noteworthy that, with the top in place there is a total absence of vibrations, rumble and resonance phenomena in the interior of the car – also a success of the loving attention lavished on the adaptation of the space frame, wheel suspension and wheels, an adaptation that has been optimally solved.”
In 1960 “auto motor und sport”, Germany, No. 15, 1960, published a detailed test report on the Mercedes-Benz 190 SL: “The 190 SL owes its good reputation not just to its elegant appearance, but also to its robustness and reliability and its accurate handling. The good build quality of the body and the roadster soft top deserve special mention.”
Technical highlights of the Mercedes-Benz 190 SL (W 121)
- Advanced four-cylinder engine with one overhead camshaft
- State-of-the-art suspension for high-level ride comfort and safety
- Retractable roadster top
|Production period: |
pre-production to end
|Number of units|
|190 SL||W 121 B II||1955-1963||25,881*|
* Roadsters and Coupés.
A new openness: Mercedes-Benz 300 SL Roadster, W 198 II series (1957-1963)
- Farewell to the Gullwing
- Hard top optional
- Improved suspension and engine
At the Geneva Motor Show in March 1957, Mercedes-Benz presented the roadster version of the 300 SL as the successor of the Gullwing coupé. From the start, Maximilian E. Hoffman had asked for this vehicle for the US market, since he saw greater chances for an open car there than for a coupé.
Technically speaking, the Roadster was broadly similar to the coupé: modification to the side sections of the tubular space frame made it possible to reduce the sill height enough to accomodate normal doors.
A fundamental improvement: the rear-axle suspension. The single-joint low-pivot swing axle – familiar from the 220 W – was installed in the 300 SL Roadster in an adapted form, being equipped for the first time with a compensating spring. This greatly improved the handling characteristics over those of the original swing axle of the Gullwing coupé.
From 1958 onwards, an optional removable coupé roof with a generous wrap-around rear window was available at a price of 1500 Marks; this could be retrofitted. Noteworthy was the rear window, swinging round far into the sides, and the consummate design of the hard top.
Two technical modifications that were incorporated into the production in the course of its six year run are particularly worthy of mention: in March 1961, the 300 SL was equipped with Dunlop front and rear disc brakes, and from March 1962 a modified engine with a light-metal block was installed.
At this time there was a special version of the 300 SL Roadster: the 300 SLS, only two units of which were ever built especially for participation in the North American Sports Car Championship. The reason for this special version was the wish for publicity-effective participation in races in the USA in order to promote sales of the Roadster.
The use of the regular production version met with the objection of the Sports Car Club of America to permit participation of the new model already in the 1957 season in the “Standard production” vehicle category. In order to have a chance at least in the only alternative vehicle category remaining, D, the production Roadster was pared down ruthlessly to become the SLS.
On the outside the 300 SLS can be distinguished by the absence of bumpers, by its specially-shaped cockpit cover with air intake slot, the low racing winscreen and the roll-over bar behind the driver’s seat. The work carried out in the Daimler-Benz research department was successful and Paul O’Shea won the North American Sports Car Championship in category “D” far ahead of its competitors.
Production of the 300 SL ended concurrently with the end of production of the 190 SL on 8 February 1963 in Sindelfingen, a date that marks the close of an era: after the production of the 300 model ended in March 1962, only the 300 SL had remained as the last passenger car model with a separate frame in Mercedes-Benz’s production programme.
Both versions of the 300 SL, Roadster and Gullwing coupé were right from the very beginning enthusiasts’ cars that have lost nothing of their allure to this day, for many years they have been among the most sought-after and valued classics.
Technical highlights of the Mercedes-Benz 300 SL Roadster (W 198 II)
- Introduction of Dunlop disc brakes and light-metal engine block
- Rear-axle suspension with single-joint swing axle
- Optional removable coupé roof
|Production period: |
pre-production to end
|Number of units|
|300 SL Roadster||W 198 II||1957-1963||1,858*|
* Roadsters and Roadsters with coupé roof.
The “Pagoda” drives up: Mercedes-Benz SL, W 113 series (1963-1971)
- A comfortable two-seater touring car featuring high performance and optimum handling safety
- Its characteristic roof shape gave it its nickname
- First SL with a safety body based on Béla Barényi’s principle
The Geneva Motor Show of March 1963 was the scene of a remarkable and well-regarded première: Daimler-Benz presented the Mercedes-Benz 230 SL, a new sports car to replace two models of the previous sales range. Its two predecessors, the 190 SL (W 121) and 300 SL (W 198), were extremely popular and successful from the start. The 300 SL in particular was already a living legend.
The new model took a middle course between the concepts of the 190 SL and the 300 SL: the 230 SL, internally designated as W 113 series, held the balance between the sporty tuning of a classic roadster but added to them the comfort of a two-seater touring car featuring high performance and the most advanced features for optimum driving safety.
The 230 SL was available from summer 1963 in three versions: an open-top car with a folding soft top that could be operated with the greatest of ease – that in itself was a minor sensation; an open-top version with hardtop, and finally as hardtop coupé.
The hardtop coupé had no soft top and soft-top compartment, but more room for luggage instead. All three versions could be driven with the top open. As an optional extra a rear transverse seat was available, as in the 190 SL.
The exterior of the 230 SL was characterised by clear, straight lines and the unmistakable SL face including the large, centrally positioned Mercedes star. The bonnet had a slight additional bulge in the middle to provide space for the vertically-installed six-cylinder engine.
The boot was generously dimensioned. The hardtop with high windows and a roof borne up only by slim pillars conveyed an impression of lightness which simply did not match the stereotype of a sports car. With its inwardly-directed curvature it reminds one of Far Eastern temples, and straightaway the car had a nickname before it really even hit the road: “Pagoda”. In addition, because of its shape the hardtop made it easier to get in and out of the car.
Apart from the wheelbase – the magic number of 2400 millimetres was taken unchanged from the 190 SL and 300 SL models – the new SL had practically nothing in common with its two predecessors. All the same, the W 113 series was not an entirely new design since its technical concept largely conformed to that of the 220 SE (W 111/3).
The SL used the “tailfin” frame-floor assembly, albeit shortened and reinforced, including front and rear wheel suspension.
In addition to the standard four-speed manual transmission, for the first time in an SL a four-speed automatic transmission was available as an optional extra. A five-speed manual transmission produced by Zahnradfabrik Friedrichshafen (ZF) was added as third variant in May 1966.
Safety is the new word
The “Pagoda” was the first SL in which sporty speed combined with safety as a design objective. Since its basis was the floor unit of the famed “Tailfin”, the world’s first saloon with a safety body, this SL also had a rigid passenger cell and crumple zones in the form of easily deformable front and rear segments.
This design went back to engineer Béla Barényi, responsible for many of the safety features in cars of the Mercedes-Benz brand. As in the saloon the interior was designed so as to reduce injury hazards in accidents, by eliminating hard corners and edges. As in the previous model, seat belts were available as an optional extra.
The steering gear was moved from the crash-imperilled front section to the firewall; the steering column yielding to axial compression and additionally featuring a joint that prevented the feared lance effect in an accident. In 1967, the telescoping safety steering column and the impact absorber in the steering wheel were added.
Chassis, engine, and transmission
The chassis, adopted from the 220 SE (W 111) Saloon, was tuned to the requirements of the sporty car, featuring recirculating ball steering, a dual-circuit brake system and disc brakes on the front wheels. The suspension was taut, but for a sports car almost atypically comfortable. Damping was provided by gas-filled shock absorbers, and for the first time a Mercedes-Benz passenger car rode on radial-ply tyres.
The six-cylinder engine, which also came from the saloon, underwent several major changes, the most important of which was the transition from a two-plunger injection pump to a six-plunger unit. This made it possible to “shoot” the fuel directly through the preheated intake port and the opened intake valves into the combustion chamber, and not just into the intake pipe, as before.
The M 127 II engine, its bore enlarged to give it a displacement of 2.3 litres, thus developed 150 bhp (110 kW) at 5500 rpm and delivered torque of 196 newton metres at 4200 rpm. Designed very sportily, this drive unit for the SL delighted in high engine speeds but did not take so kindly to underrevving.
The four-speed transmission, likewise from the saloon construction kit, was designed with a slightly lower ratio in 1st gear to achieve sportier acceleration. It sprinted from 0 to 100 km/h in 9.7 seconds. The top speed of the fabric-roofed 230 SL was 200 km/h, the hard-top version only marginally lower at 196 km/h.
The variant with the optional automatic transmission reached a top speed of 195 km/h. In the eyes of sports car purists the automatic is almost immoral. But history teaches us a different lesson: by the time the “Pagoda” was discontinued the automatic transmission’s share was around 77 per cent.
It was much the same with the power steering that was also available at extra cost. The W 113 series was a pioneer also on that score: all subsequent SL models always pair exceptionally good performance with highest levels of comfort. The respectable number of 19,831 units of the 230 SL were built.
Successors with higher displacements
On 27 February 1967, Mercedes-Benz presented the 250 SL, which replaced the 230 SL that had been produced for four years. On the outside the new car, whose series production had already begun in December 1966, was indistinguishable from its predecessor.
The changes concerned mainly the engine and the brake system. Both were taken, slightly modified, from the 250 SE (W 108 III). The M 129 III engine, its displacement enlarged by 200 cubic centimetres, had the same output as the 230 SL, 150 bhp (110 kW) at 5500 rpm, but 10 per cent more torque and a flatter torque curve.
It was now provided with seven crankshaft bearings for smoother operation, and with an oil/water heat exchanger as well; only the future 280 SL would be fitted with an air/oil cooler. The 250 SL thus was appreciably more flexible in operation, but did not quite reach the previous model’s top speed owing to its higher weight.
The 250 SL’s top speed with four-speed manual transmission was 195 km/h or 200 km/h depending on the final drive ratio (standard: 1:3.92; optional: 1:3.69; automatic transmission: 190 km/h or 195 km/h). With five-speed manual transmission it was available in only one variant (1:4.08), which reached 200 km/h.
The changes to the brake system included disc brakes on the rear wheels as well, larger brake discs at the front, and the fitting of a brake power regulator to prevent rear wheel overbraking. As an optional extra a differential lock was now available. A fuel tank capacity of 82 litres instead of the previous 65 permitted an extended cruising range.
In addition to the three body versions known from the 230 SL, the 250 SL was available as an optional extra in a fourth version, a coupé with rear seat bench, which was shown for the first time in March 1967 at the Geneva Motor Show. In this so-called California version, the necessary space for the rear bench seat had been obtained by eliminating soft top and soft-top compartment.
Since the soft top could not be retrofitted, this variant promised unspoilt driving pleasure only in dry regions or with mounted coupé roof.
Less than a year after the presentation of the 250 SL, after 5196 units had been built it was replaced by the 280 SL. Apart from the model plate it could only be distinguished from the two preceding models on the outside by the different wheel hub caps.
In the wake of the market launch of the intermediate range models of the 114/115 series, not only the luxury-class saloons, coupés and cabriolets, but also the SL was powered by a 2.8-litre engine. Thanks to a camshaft with changed valve timing, the variant of the M 130 engine used in the 280 SL mobilised 10 bhp (7.4 kW) more than the base version of the 280 SE, developing 170 bhp (125 kW) at 5750 rpm.
Compared with the 250 SL the power had been increased by around 20 bhp (15 kW) and torque by 10 per cent. For the first time the radiator fan was fitted with a viscous coupling which limited the rotational speed. The 0 to 100 km/h was in the vicinity of nine seconds and the top speed again came up to the level of the 230 SL, i.e., 200 km/h in the fabric-top version. Its suspension, designed for further enhanced comfort, was softer. The service intervals were 10,000 kilometres instead of 3000.
23,885 units of the fast and reliable Mercedes-Benz 280 SL rolled off the assembly line. All in all, from 1963 to 1971 a total of 48,912 “Pagodas” were built – remarkable for a sports car with such high standards. Today its high overall quality, its elegance and its clear lines make the W 113 series a coveted item among restorers and collectors.
The W 113 series in the press
The motor magazine “auto motor und sport”, Germany, No. 6, 1963, characterised the Mercedes-Benz 230 SL: “A sports car that does 200 km/h, goes from 0 to 100 km/h in less than ten seconds, yet has the smooth engine running characteristics and comfort of a touring car.”
A detailed test report in “auto motor und sport”, Germany, No. 21, 1963, added: “The upshot: the 230 SL is one of the most refined sports cars ever. All the same it deserves to be numbered among the truly sporty vehicles because it not only delivers sporty performance, but is as compact and safe-handling as should be expected of a sports car. […]
And finally, you can push the 230 SL at a very fast pace if you wish, but you can also maintain the slowcoach tempo that traffic conditions so frequently force upon us.”
“Road & Track” wrote the following about the 280 SL in its August 1968 issue: “The ride, over all sorts of roads, is fantastic. The body is absolutely rigid and rattle-free, regardless of which top is installed, and the supple suspension just works away down there without disturbing the superb poise of the SL.”
Technical highlights of the Mercedes-Benz SL, W 113 series
- Extremely easy-to-handle folding top
- Six-cylinder engine with six-plunger fuel injection pump
- For the first time, automatic transmission available for an SL
- Safety bodywork with rigid passenger cell and deformable front and rear segments
- Numerous further safety features such as interior devoid of sharp edges and angled steering column
- Disc brakes on front axle, from 1967 onwards, on rear axle as well
|Production period: |
pre-production to end
|Number of units|
|230 SL||W 113||1963-1967||19,831|
|250 SL||W 113 A||1966-1968||5,196|
|280 SL||W 113 E 28||1967-1971||23,885|
18 years production time: the Mercedes-Benz SL, R 107 series (1971-1989)
- A total of 237,287 open-top two-seaters produced in 18 years
- Engines again and again updated to the state of the art
- Coupés of the SLC series available until 1981 parallel to the open-top version
- The first SL with eight cylinders
In April 1971, a new SL rolled out onto the highway, the Mercedes-Benz 350 SL. For the first time in the history of the model series an eight-cylinder power plant did duty under the long bonnet. From all sides it made the impression of a strong, self-confident, imposing open-top vehicle.
Its parents also gave it an equally well designed, removable coupé roof for the road. Besides elegance and quality the body radiated safety, since the crash behaviour of the two-seater was far ahead of its time.
A hard decision
The decision to manufacture the R 107 series (for the first time an SL series received the internal designation “R” as in Roadster instead of “W” as in Wagen = car) was taken by the Board of Management after intensive debates on 18 June 1968.
At issue was whether there should be a Targa roof version, i.e., one with a removable roof panel, instead of the fabric-topped variant, because owing to higher safety standards alarming news was to be heard from the USA regarding the licensing of open-top cars.
That a decision was finally made in favour of an open-top two-seater with a fabric roof and an additional removable hard top can be attributed to Hans Scherenberg, the head of Development, who fought tooth and nail for it: “The SL gave me great pleasure, but also caused me great trouble. This was no easy decision for us,” he summed up the decisive meeting.
The history of the roadster is intimately linked to that of the coupé. For the coupé question still remained unanswered. It was not decided that day. Discussion centred around whether one should additionally, and soon, make a four-seater sports coupé based on the R 107 series, or wait for the coming S-Class (W 116) to build it on that basis. But then a production model would not have arrived until much later, in the mid-1970s.
Karl Wilfert, then Head of Body Design in Sindelfingen, developed – pretty much on his own authority – a coupé based on the R 107 and presented it one day to the Board of Management as a “rough draft”. Rejected at first, Wilfert managed to push through his idea of a sports coupé with the tenacity which was so characteristic of him.
And so just six months after its première the SL was followed in October 1971 by a comfortable four-seater sports coupé, the 350 SLC, whose unconventional lines also found it many friends around the world in the course of the years. Internally the series was designated C 107 (the “C” stands for “coupé”).
Up to the windscreen its appearance matched that of the open-top variant; behind the windscreen the overall height and length grew. A flat roof spanned the four-seater passenger compartment in a gentle curve, going over into a large and very steep rear window that arched in two directions. The boot lid was slightly convex in shape, unlike the SL’s.
In the side prospect the length of the coupé is documented, firstly, by the 360-millimetre longer wheelbase (2820 millimetres versus 2460), secondly by the line of the side windows. Without interfering B-pillars they were completely retractable, as is usual in a Mercedes-Benz coupé.
The SLC’s drag coefficient was better than that of the SL so that the coupé attained the same performance despite an added weight of some 50 kilograms. A particularly noteworthy fact is that it fully lived up to its classification as a “Sports Coupé”, gaining wins for Mercedes-Benz in many rallies and long-distance races.
Safety as agenda
Béla Barényi’s safety concept with front and rear crumple zones and a rigid passenger cell found expression in the 107 series in a further developed form.
The backbone of the R 107 is not simply a shortened and reinforced Saloon floor assembly, as in the predecessor, but an independent frame-floor unit with a closed transmission tunnel and box-shaped cross and longitudinal members which featured differing sheet metal thicknesses and a resultant carefully defined crumple pattern.
The SL definitely had to be an open-top car, and that being the case the only protection in a possible roll-over would be provided by the A-pillar plus windscreen. They were thoroughly redesigned and had 50 per cent more strength to show than in the previously-built version.
In addition, to enhance its strength the windscreen was bonded into the frame. This resulted in a remarkable power of resistance in the roof-drop test with the result that it was possible to license the open-top car for the USA even without a Targa bar. To complete the logic the rear window of the hardtop was also bonded into its frame.
In the interior there were pioneering changes to report, as well. The hard dashboard made way for an ingenious sheet-steel design that yielded on impact both in the top section and the knee area and was foam-padded. The switches and levers were recessed.
The four-spoke steering wheel based on the latest findings of accident researchers, was also new. The proven impact absorber was still in place, but the steering-wheel rim, spokes, padded boss and hub were covered with polyurethane foam. As further safety feature the fuel tank was no longer installed in the rear end but above the rear axle, protected against collision.
From March 1980, the anti-lock braking system ABS was offered; from January 1982, also airbag and belt tensioner.
A bestseller right off the bat
But it was not the safety aspects that motivated customers around the world to quickly reach for the new SL. It was the promise of an open-top automobile that was a successful piece of engineering all round – and it was in fact the only one of its kind offered in the USA over a period of several years .
Its distinctive front end with the dominant SL face, the wide-band headlamps and grooved turn indicator covers had a powerful aura; the lines of the low silhouette were harmonious – soft top open or closed, or with hardtop. And the very slight inward curve of the boot lid, along with the concave hardtop, were reminiscent of “Pagoda” days. The wide-band tail lights with their ribbed surface not only were largely insensitive to soiling, but additionally gave the rear end a touch of vigour.
Extremely conducive to comfort and ease of operation was the easily and speedily operated soft top, a refined version of the “Pagoda” top. It took just 30 seconds to open or close it. Folded, it disappeared underneath a cover that was meanwhile customary in the SL series.
A number of details underscored the car’s safety aspirations. The seats were available from the start with head restraints, and seat belts also were included. Physical well-being and driver-fitness safety were served by the heating system with its very spontaneous response, supported by new air ducting in the doors.
Newly developed wind-deflecting mouldings on the A-pillars, which also served to channel off mud-laden water in the rain, and dirt-repelling covers on the exterior mirrors enabled good visibility. They kept the side windows clean even in inclement weather.
The windscreen wipers arranged closely to each other in the centre of the car swept a respectable 70 per cent of the windscreen area, were always optimally positioned in the flow of air and did not lift off even at higher speeds.
Engines with catalytic converter
During its 18-year “production time” (which was not planned to last that long, but in the end was indeed successful), the R 107 was driven by a whole series of six- and eight-cylinder engines. Its model designations are accordingly quite varied.
The eight-cylinder models were led by the 350 SL (1971 to 1980), whose 3.5-litre engine (M 116) already was known from the W 108, W 109 and W 111 series. The 147 kW (200 bhp) which it delivered at 5800 rpm helped the sports car, which weighed 1600 kilograms after all, to clock nine seconds for 0 to 100 km/h and reach a top speed of 210 km/h. The 350 SLC had identical performance figures.
From autumn 1971 onwards, the 450 SL was produced, initially for the US market. At 5000 rpm its M 117 engine delivered 132 kW (180 bhp) in the California version and 140 kW (190 bhp) in the version for the other states, and from 1973 on, and 165 kW (225 bhp) in the European version.
Top speed was 215 km/h: it surged from 0 to 100 km/h in 8.8 seconds. In 1972, the 450 SLC, the corresponding coupé version, followed, with identical engine and identical performance. Prior to March 1973, both were destined exclusively for export to North America, after that they were included in the general sales range.
In July 1974, the SL model range was extended: the SL and SLC were now available as models 280 SL and 280 SLC with the 2.8-litre M 110 engine. It developed 136 kW (185 bhp) at 6000 rpm and had proven its reliability in the two years before in the “Stroke Eight” series W 114/115 and in the W 116-series S-Class. Both models had identical performance: the top speed was 205 km/h; they could sprint from 0 to 100 km/h in 10.1 seconds.
Thus three SL engines were now available to choose from – nothing unusual nowadays, but a real innovation for this model category in those days. Only the attentive observer could distinguish between the three variants: The 280 SL could be recognised by its tyres, narrower than those of the 350 SL and the 450 SL.
In addition, the 450 SL featured a discreet front spoiler attached to the rear lower end of the front apron and which significantly increased the radiator’s air throughput.
Between November 1975 and February 1976, the fuel injection systems of all three engines were changed for better compliance with emission standards, which had meanwhile also become stiffer in most European countries. The electronically-controlled Bosch D-Jetronic was abandoned for the newly-developed mechanically-controlled Bosch K-Jetronic.
The adaptation entailed minor losses in output in all three cases: in the 280 SL to 130 kW (177 bhp) at 6000 rpm, in the 350 SL to 143 kW (194 bhp) at 5500 rpm, and in the 450 SL to 160 kW (218 bhp) at 5000 rpm.
At the same time the compression ratios of the 2.8 and 3.5-litre engines were slightly reduced. In addition, the 3.5 and 4.5-litre engines were equipped with a contactless transistorised ignition system and hydraulic valve clearance compensation to facilitate maintenance.
The compression ratio of the 2.8-litre unit was raised to the old figure again in April 1978. With a few supporting measures the engine then regained its earlier power potential of 136 kW (185 bhp), which it now delivered already at 5800 rpm.
In September 1977, Mercedes-Benz launched the 450 SLC 5.0 with a V8 engine (M 117) enlarged to a displacement of five litres. A hidden innovation was the first-time application of hypereutectic cylinder contact surface machining, a special smelting process which made it unnecessary to insert cylinder liners.
The engine delivered 177 kW (241 bhp) at 5000 rpm, good for 0 to 100 km/h acceleration in 8.5 seconds and a top speed of 225 km/h. The vehicle’s bonnet and boot lid were made of aluminium, and it had light-alloy wheels as standard. On the outside the 450 SLC 5.0 was recognisable by, among other things, a narrow spoiler on the rear end.
Revising the series
At the Geneva Motor Show in March 1980, Mercedes-Benz presented the SL and SLC in updated form. Their interior appointments, including the steering wheel were harmonised with those of the 126-series S-Class, and the engineering was brought up to the same level.
The previous three-speed automatic transmission with torque converter was replaced with a four-speed variant. Models 280 SL and 280 SLC were given a five-speed manual transmission as basic equipment. In addition, the hardtop was now included in the standard specifications of the open-top variant. But above all the light-alloy eight-cylinder engines of the 126-series S-Class, slightly modified, made their arrival in the 107-series.
The six-cylinder engine of the 280 SLC remained unchanged.
The new 500 SL, equipped with the 5.0-litre V8 (M 117) familiar from the 450 SLC 5.0, replaced the 450 SL and delivered an output of 177 kW (241 bhp) at 5000 rpm, to give the new top-of-the-range model a 0 to 100 km/h acceleration of 7.8 seconds and a top speed of 225 km/h.
Models 350 SL and 350 SLC were sent off into retirement after nine years of production. Their successors were the 380 SL and 380 SLC, whose 3.8-litre light-alloy engine (M 116), with 160 kW (218 bhp) at 5500 rpm, originated after the pattern of the five-litre unit, by enlarging the bore of the long-serving 3.5-litre V8 with grey cast iron cylinder block.
Both models attained top speeds of 215 km/h and accelerated to 100 km/h from a standstill in just 9 seconds. From the outside the new models were almost indistinguishable from the previous models, except for the badge with the model designation.
All three SL models had now a light-alloy bonnet and the discreet front spoiler familiar from the 450 SLC 5.0; the 500 SL was also given a light-alloy boot lid with a black plastic rear spoiler, already familiar from the five-litre coupé.
In autumn 1981, both V8 engines were thoroughly redesigned in the context of the “Mercedes-Benz Energy Concept” to reduce their consumption and pollutant emissions. Along with an increase in compression ratio the measures included camshafts with variable valve timing, air-bathed injection valves, and an electronic idling speed control.
Owing to the altered camshaft tuning the maximum torque could be shifted to a lower engine speed range and, in the case of the 3.8-litre engine, even increased. This power plant underwent particularly far-reaching changes: to get a more favourable volume-to-surface ratio the bore was reduced and the stroke increased.
The modified 3.8-litre V8 thus had a slightly larger displacement. In both eight-cylinders, in exchange, so to speak, for the improved economy, minor losses in power had to be accepted, output dropping to 150 kW (204 bhp) at 5250 rpm in the 380 SL and to 170 kW (231 bhp) at 4750 rpm in the 500 SL.
As in the 126 series the final drive ratio was adjusted to the changed engine characteristics and made higher, from 3.27 to 2.47 in the 380 SL and from 2.72 to 2.24 in the 500 SL.
For the SLC Coupés these changes came too late, however: at the Frankfurt on the Main International Motor Show in September 1981, along with the “Mercedes-Benz Energy Concept” the 380 SEC and 500 SEC models of the C 126 series were presented, spelling retirement for the SLC models, which had been built for exactly ten years.
But even after ten years of production there was no thought of a replacement for the SL models; what’s more, four years after the Energy Concept was presented, they came in for extensive refinements, and so in September 1985, again at the Frankfurt show, a completely revised SL model range was introduced.
The emphasis was on a restructured engine range. A discreet facelift, primarily recognisable from the front spoiler and wheels with aluminium rims (diameter: 38.10 centimetres), was also part of the package. The front axle was reworked and the brakes enlarged with fixed callipers. To prevent the cars from pulling to one side when braking, the steering offset was reduced.
A comprehensive facelift
All engines were available in two versions: with a catalytic converter and slightly lower output, and as so-called catalyst retrofit version without a catalytic converter. The catalyst retrofit versions could be equipped later on with a catalytic converter, for example when the widespread supply of unleaded petrol was ensured, and had their ignition system, electronics and cable harness prepared for this.
A newly-designed 3.0-litre six-cylinder engine (M 103) which had made its first appearance in the 300 E of the mid-range W 124 series nine months earlier replaced the tried and tested 2.8-litre engine, as it had already done previously in the respective S-Class Saloon.
As a result the 280 SL was discontinued, and after a 22-year interruption there was again a sports car with the magic model designation 300 SL. It delivered an output of 138 kW (188 bhp) at 5700 rpm without catalytic converter (top speed: 203 km/h; 0 to 100 km/h in 9.6 seconds) and 132 kW (179 bhp) with catalytic converter (200 km/h; 9.9 seconds).
A new addition to the range was the 420 SL with the 4.2-litre V8 engine (M 116), which delivered 160 kW (218 bhp) at 5200 rpm without a catalytic converter and 150 kW (204 bhp) with one. It was created by adopting the bore of the original 3.8-litre engine and combining it with the stroke of the “Mercedes-Benz Energy Concept” 3.8-litre engine, and it now replaced that unit in the SL, the S-Class Saloon and the SEC Coupé.
The 420 SL accelerated from 0 to 100 km/h in 8.5 seconds (with catalytic converter: 9 seconds) and reached a top speed of 213 km/h (205 km/h).
The 5.0-litre engine (M 117) was modified, too; with catalytic converter operation in mind it now had an electronic ignition system and the electronically/mechanically controlled Bosch KE-Jetronic injection system, delivering 180 kW (245 bhp) at 4750 rpm. With a catalytic converter the output was 164 kW (223 bhp) at 4700 rpm. These values helped the 500 SL reach a top speed of 225 km/h (with catalytic converter: 215 km/h) and accelerate from 0 to 100 km/h in 7.3 seconds (7.8 seconds).
The most spectacular new development in the engine range was a 5.6-litre eight-cylinder engine (M 117), which was created by increasing the stroke of the 5.0-litre V8 and which gave the SL an output of 170 kW (231 bhp) at 4750 rpm. The 560 SL was reserved for the USA, Australia and Japan export markets. Fitted with an emission control system in the US version it had a top speed of 223 km/h and sprinted from 0 to 100 km/h in 7.7 seconds.
Production of the R 107 series ended in August 1989, more than 18 years after start-up of the 350 SL. This SL series set an internal record that will probably never be broken: in the entire history of the company no other passenger car series has ever been produced over such a long period, with the exception of the G-Class.
All told, in Sindelfingen 237,287 open-top cars were built, a number which impressively demonstrates the great popularity of the 107 series. Of the coupé a total of 62,888 units were built from 1971 to 1981.
The R 107 series in the press
In a first test of the Mercedes-Benz 350 SL “auto motor und sport”, Germany, No. 9/1971, wrote: “Good suspension comfort, definitely up to saloon standard, proves to be an essential feature of the 350 SL: at low and high speeds it absorbs big bumps well and takes small bumps in a way that they are never a disturbance even on very poor roads.”
In 1986, “Road & Track”, USA, No. 11/1986, compared the Mercedes-Benz 560 SL, which was in the last era of its production, with the Cadillac Allanté and summed up: “Legendary quality is Mercedes’ primary stock in trade. But brilliant performance and outstanding ABS braking have freshened [the vehicle] this year. Against these attributes, Cadillac brings better handling and greater luxury to bear while failing to match Mercedes’ performance and quality.”
“auto motor und sport”, Germany, No. 5/1986, reported: “In curves, too, the modified SL displays a behaviour that does not go well with the image one tends to have of the vehicle. With its precise power-assisted steering, extremely high possible transversal acceleration and now only reduced load change behaviour, the long-snouted, rather staid-looking car delivers precisely that which one would expect from a purebred Gran Turismo.“
Technical highlights of the Mercedes-Benz SL, R 107 series
- Further developed safety body
- Frame floor assembly with sheet metal of different thicknesses and a resulting carefully-defined crumple behaviour
- Rugged roll-over protection: high-strength A-pillars and windscreen frame with bonded glass for greater stability
- Special air ducting in doors ensures low soiling of side windows and exterior mirrors
- Bosch K-Jetronic contactless transistorised ignition, hydraulic valve clearance compensation (1975)
- First SL with exhaust gas catalytic converter (1985)
Production figures for Mercedes-Benz SL, R 107 series and SLC, C 107 series
|Model||Internaldesignation||Production period: |
pre-production to end
|Number of units|
|280 SL||R 107 E 28||1974-1985||25,436|
|300 SL||R 107 E 30||1985-1989||13,742|
|350 SL||R 107 E 35||1971-1980||15,304|
|450 SL*||R 107 E 45||1971-1980||66,298|
|380 SL||R 107 E 38||1980-1985||53,200|
|420 SL||R 107 E 42||1985-1989||2,148|
|500 SL||R 107 E 50||1980-1985||11,812|
|560 SL**||R 107 E 56||1985-1989||49,347|
|280 SLC||C 107 E 28||1974-1981||10,666|
|350 SLC||C 107 E 35||1971-1980||13,925|
|380 SLC||C 107 E 38||1980-1981||3,789|
|450 SLC*||C 107 E 45||1972-1980||31,739|
|450 SLC 5.0||C 107 E 50||1977-1980||2,769|
|500 SLC||C 107 E 50||1980-1981||***|
* Before March 1973 only for export to North America.
** Export model for North America, Japan, and Australia.
*** Number of units contained in the figures for the 450 SLC 5.0.
Technology platform: Mercedes-Benz SL, R 129 series (1989-2001)
- Numerous innovations, from the automatic roll-over bar to the integral seat
- Debut of the twelve-cylinder engine in the SL model, R 129 series
- Official AMG versions available for the first time
At the 1989 Geneva Motor Show, Mercedes-Benz presented an SL that was a new car in every respect. The first models were the 300 SL, 300 SL-24 and 500 SL. Internally the series was designated R 129. Unlike the predecessors, its production did not take place in Sindelfingen, but in Bremen for capacity reasons.
The response was immediately extremely positive, and shortly after the presentation it was foreseeable that the planned annual production of 20,000 units would be stretched to capacity for years and delivery periods of several years would have to be accepted.
The SL face captured a permanent place in the Mercedes-Benz model hierarchy over the decades. The new SL re-interpreted the traditional basic shape of the grille: within the radiator grille, organically integrated into the bonnet, the Mercedes star was complemented by horizontal strips made of anodised aluminium.
Chief designer Bruno Sacco had done an excellent job. The stylistically assured, no-frills lines of the slightly wedge-shaped body, the flared wheel arches for the wide-base tyres, the half-spoilers forward of the front wheels, its steeply raked windscreen, skilfully modelled rear end and the standard light-alloy wheels produce an exceedingly harmonious overall effect.
The aerodynamic fine touches, including underbody and airflow through the engine compartment, added up to a fuel-saving, speed-increasing cd of 0.32 with the hardtop mounted. A cd figure of 0.40 was measured for the open-top car with closed side windows.
“Car Design Award”
Hardly a year after its launch the SL was awarded the international “Car Design Award”. The SL was the top choice of an eleven-member jury of journalists from ten countries, assisted by a representative of the city of Turin and one from the Piedmont region.
The jury stated as reason for the prize: “In the Mercedes-Benz 300 – 500 SL the ensemble of safety innovations, … exemplary ergonomic solutions, and stringent adherence to the traditional design culture of the manufacturer’s brand is convincing. The new SL embodies the most valuable elements of up-to-date industrial design, without losing the flair that distinguishes every sports cabriolet.”
High torsional stiffness
The prerequisite for the proper operation of the fully automatic folding soft top under all conditions is the extremely high torsional rigidity of the body. To reduce the vibration and torsion characteristics typical of open-top cars, additional diagonal struts are fitted in the particularly critical areas of the body.
In the front end the front axle carrier is connected with the door sills by two specially-shaped struts. In the rear end two tubular struts between the door sills and the spare wheel recess serve the same function. Owing to these measures it was possible to improve the torsional rigidity by around 30 per cent over that of the previous model, achieving a saloon-like overall rigidity achieved.
This car set new standards in the area of safety, too. The results of Mercedes-Benz’s rigorous frontal and rear-impact crash tests for the open-top vehicle were sensational and a clear proof of the scrupulous precision with which the developers had worked.
The resistance to side impact went far beyond what the law required and once again set trends for the sensible design of all details, for instance the overlapping of the doors with the sills, the cross-bracing beneath the seats, including the rigid sides of the transmission tunnel, or the high-strength steel tubes inside the A-pillars, which can withstand a roof impact.
This two-shelled structure of the front roof frame in conjunction with the bonding of the windscreen to the body results in very great stability even if a one-sided load is applied to the roof frame.
An integral part of the safety concept is the automatic roll-over bar which was realised in the SL for the first time in an automobile and has the purpose of protecting the occupants’ survival space if the car should overturn. So as not to impair open-top driving pleasure with a permanently installed, rigid rollbar, a flexible solution was implemented by which the roll-over protection was only activated if needed.
When not in use the safety bar, consisting of a U-shaped high-strength steel tube foam-padded with polyurethane, was stored in front of the soft-top compartment, closing off the rear compartment towards the back and forming a level surface with the top well lid.
If a roll-over threatens, the sensor-controlled roll-over bar is electromagnetically triggered, raised into position by the force of pre-compressed springs within 0.3 seconds and secured by pawls. The high-strength centre pillars, connected over a large area with the rear longitudinal members, serve as basis for mounting and as support.
In addition to automatic triggering in an emergency, the driver can raise and lower the bar slowly by means of a switch, with a hydraulic element carrying out the action.
Extremely sturdy integral seats
The most advanced feature of the interior design were the integral seats of the SL, a technical masterpiece of design and an important part of the safety concept. The seat frame and backrest are made of various special magnesium alloys executed in thin-wall casting technique.
They incorporate the three-point seat belt with belt tensioner, the belt height adjustment, coupled with the head restraint adjustment, and electric stepper motors for adjusting reach, height and tilt of the seat cushion and backrest. Another important feature is the automatic positive locking of the backrest. The resistance of the seat in a crash is many times higher than the forces that could possibly arise.
Twenty patents for solutions to various details went into this seat; its creator received the Paul Pietsch Prize and high prize money as acknowledgement of his pioneering work in 1989.
Fully automatic folding soft top
The newly designed electrohydraulic fabric top with which the SL is equipped as standard offers especially great operating convenience. Simply by operating a switch, within 30 seconds the soft top can be opened, folded and deposited in the narrow soft-top compartment, or taken out of the compartment and closed.
Simultaneously, the side windows and the roll-over bar are lowered and then returned to their starting positions. Up and closed, the top is taut and smooth in all directions – after all, it would be highly undesirable for the vacuum caused above the roof by the car’s movement to cause the top to balloon, and perfect operation of the roll-over bar under the closed soft top must also remain guaranteed.
The energy to operate the soft top is provided by an electrically-driven hydraulic pump located in the spare wheel recess together with the oil reservoir. The microprocessor-controlled motions are monitored with the aid of 17 limit switches, and the hydraulic system has 15 pressure cylinders and eleven solenoid valves.
The exemplary solutions included the draught-stop. Unlike the electro-hydraulic soft top it was not viewed as a high-tech marvel, but its development also involved attention to complex details. The draught-stop consists of a framed, breathable screen which can be quickly attached to the roll-over bar and which, when raised, appreciably enhances ride comfort when the soft top is open by minimising wind noise and draught.
With the draught-stop, leather jackets and caps for driver and front passenger are a thing of the past, as is tousled hair for the ladies. Even high speeds no longer cause draught problems, and open-top driving at low temperatures becomes a real show. Today the innovative draught-stop, for which the inventors hold four patents, is practically taken for granted in many convertibles around the world.
The standard hardtop was now made of aluminium, and despite larger windows weighed just 34 kilograms, about ten kilos less than the coupé roof of the previous model. As it was, consistent lightweight design and the extensive use of high-strength sheet steel had enabled the creation of a bodyshell weighing 405 kilograms, only 20 kilograms more than that of the previous model, despite substantial improvements in structural safety.
Electrically-operated windows and the electro-pneumatic central locking system, both standard equipment in all SL models, served comfort and convenience. The basic equipment of the 500 SL also included electric steering column adjustment for optimum adaptation of reach, height and tilt to the driver.
A new suspension
The suspension conformed in principle to the familiar suspension design of the Saloons of the 201 and 124 series. The new SL models thus had a coil-spring shock absorber independent front suspension with anti-dive control and wishbones, gas-filled shock absorbers and stabiliser, and a modified multi-link independent rear suspension with anti-squat and anti-dive control, coil springs, gas-filled shock absorbers and stabiliser.
This guaranteed excellent handling characteristics. Many components were adapted to the altered installation conditions, stresses and loads in the SL; the axle geometry, too, was matched to the special demands on the driving characteristics and comfort.
As an optional extra a newly-developed auxiliary system was also available representing the most advanced suspension technology realisable at the time, combining three subsystems. The purpose of this level adjustment and regulation on front and rear axle was to maintain a constant vehicle level with the engine running.
The automatic speed-dependent level adjustment function lowered or raised the vehicle level depending on the actual speed; for driving on poor roads the level could be increased by 30 millimetres; at a speed of more than 72 km/h the system adjusted to the normal level, and above a speed of 122 km/h the vehicle was lowered by 15 millimetres.
The third component, the ADS Adaptive Damping System, used adjustable shock absorbers and a complex electronic control system to adapt the damping fully automatically, as needed, and within fractions of a second, to the driving state determined by five sensors. The overall sprung mass vibrations were reduced in accordance with vehicle load, road condition and style of driving. This was virtually a preliminary stage of the active suspension that reached production maturity in 1999 in the C 215-series Coupé.
In keeping with their sports credentials, all models of the R 129 series were fitted as standard with 15-hole light-alloy wheels (diameter: 40.64 centimetres) and wide-base tyres size 225/55 ZR 16. The larger wheels compared with the previous models permitted installing large brakes appropriate to the improved performance of the SL.
New were the front fixed-calliper disc brakes featuring four pistons, two pairs with different diameters each. This design, used for the first time in a Mercedes-Benz passenger car, ensures even brake pad wear and better utilisation of the pad volume. The front and rear disc brakes are internally ventilated. The ABS Anti-lock Braking System was part of the standard configuration of all three models.
From September 1995 on the Electronic Stability Program ESP® was available for the SL 500 as an optional extra. It was standard equipment for the SL 600. From December 1996 onwards the six-cylinder models could also be equipped with ESP® if they were ordered with the electronically-controlled automatic transmission available from June 1996.
Another world first in the interests of active safety also saw use at this time: the BAS Brake Assist, installed as standard from December 1996 in all models of the 129 and 140 series. BAS is able to detect emergency braking and, in case of need, automatically build up the maximum brake boosting effect more rapidly than before.
This distinctly reduced the braking distance of the vehicle. In early April 1998, the Electronic Stability Program ESP® was included as standard equipment of the SL 500 and SL 60 AMG; in August 1999 it also became a standard feature in the two six-cylinder models, SL 280 and SL 320.
The first facelift
Visually and technically updated SL models were presented at the Frankfurt International Motor Show in September 1995. The facelifted variants were distinguished by a modified body design, more extensive standard equipment, and more refined engineering.
The body design modifications were of a minor nature and ranged from redesigned front and rear bumpers, transparent glass covers for the front turn indicators, and a subtle change in the radiator grille, which now had six slats. The side skirts, like the bumpers, were no longer painted in a contrasting colour, but in the colour of the car, and had modified breathers, a prominent feature serving to identify the facelifted models.
Other new items were the bichromatic tail lights with their uniform red appearance, and 12-hole light-alloy wheels, the standard for all SL models. As an optional extra a glass sunroof with sunblind was available; it could be fitted in place of the usual aluminium hardtop. In the interior, the door trim, steering wheel and seat design were modified.
Headlamps with xenon gas discharge lamps, first introduced a few months earlier in the 210-series E-Class, were now also available for the SL. The new xenon lamps were twice as powerful as the conventional halogen headlamps and ensured better, brighter illumination of the roadway. Dynamic headlamp range adjustment prevented dazzling of oncoming traffic.
A world first was introduced simultaneously in the SL-Class and the S-Class. As first carmaker Mercedes-Benz was able to present an improved cruise control which could regulate the speed down to 30 km/h; the facelifted SL models were equipped with this function as standard.
The second facelift
The second facelift took place in 1998, involving only a few modifications to the design of the SL: the purpose of the discreet stylistic touch-ups was to give the sports car an even more dynamic appearance. This was achieved with a slightly modified rear end in which the now monochromatic glass covers of the tail lights presented themselves in a gentler look with only three ribs.
New oval tailpipe trim for the exhaust system including adjustments on the bumper emphasised the car’s sporty looks. A round shape was the dominant feature of the new exterior mirrors, adapted to the design of the SLK and the most important external identifier of the facelifted models.
The door handles and detachable body parts of the facelifted SL models had a high-gloss finish in the vehicle body colour. The size and design of the wheels were modified, too: the SL models now had newly designed five-hole light-alloy wheels and rode on size 245/45 ZR 17 tyres as standard.
Proven engine technology right from the start
All three engines of the original SL portfolio in the R 129 series feature a closed-loop catalytic emission control system as standard. The entry-level engine was the two-valve-per-cylinder six-cylinder engine (M 103) in the 300 SL (1989 to 1993) with an output of 140 kW (190 bhp). It had already served well in the saloons of the 124- and 126-series, but was revised for use in the SL.
The most important improvements were: a redesigned combustion chamber, which reduced the emissions of unburned hydrocarbons, and a modified emission control system. By eliminating the close-coupled primary catalytic converter, which was subjected to high thermal stresses, and enlarging the cross-section of the exhaust pipes and the now two-pipe catalytic converter it was possible to raise the rated output of the engine from 132 kW (179 bhp) to 140 kW (190 bhp). The top speed was 228 km/h; 9.3 seconds was the figure stated for accelerating from 0 to 100 km/h.
From 1989 to 1993 there was also the 300 SL-24 model featuring a newly designed four-valve-per-cylinder six-cylinder engine (M 104). This engine was based on the M 103, and its parts were mostly identical with those of its two-valve counterpart. New were the four-valve cylinder head and map-controlled electronic intake camshaft adjustment, used for the first time at Mercedes-Benz.
In conjunction with a higher compression ratio and an electronic ignition system with anti-knock control, the result was a 29 kW (39 bhp) increase in output over the M 103 to 170 kW (231 bhp). The performance of the 300 SL-24 was thus noticeably sportier despite almost identical fuel consumption (top speed: 240 km/h, 0 to 100 km/h: 8.4 seconds), but this had to be bought at an additional cost of almost DM 10,000.
The successors to these two models in the years 1993 to 1998 were the SL 280 (2.8 litres displacement, 142 kW/193 bhp) and SL 320 (3.2 litres displacement, 170 kW/231 bhp), both with four-valve-per-cylinder six-cylinder engines from the M 104 series.
The car that attracted particular attention at the 1989 Geneva Motor Show was the 500 SL, which as top-of-the-range model had a 240 kW (326 bhp) 5.0-litre four-valve-per-cylinder V8 engine (M 119), making it the most powerful Mercedes-Benz production car at the time.
The design of this engine was based on the 5.0-litre M 117 light-alloy engine, which had stood the test of over ten years’ time. Crankcase, crankshaft, and connecting rods were extensively modified to obtain the higher output figures. The two four-valve cylinder heads were of new design and had adjustable intake camshafts as did the four-valve-per-cylinder six-cylinder engine.
Decisive for the marked increase in output (an increase of 60 kW/82 bhp), along with conversion to the four-valve-per-cylinder technology, were the anti-knock control, a new two-box air filter with reduced suction resistance, and, not least of all, changes in the emission control system: like the two six-cylinder units the four-valve V8 had a two-pipe catalytic converter with a larger cross-section instead of a primary catalytic converter.
This power potential gave the 500 SL impressive performance to outclass its predecessor: from a standing start the top-of-the-range model sped from 0 to 100 km/h in 6.2 seconds; its top speed was electronically limited to 250 km/h.
In autumn 1992, when the 600 SL appeared, the engine of the 500 SL underwent minor changes. The version of the four-valve V8 with Bosch KE-Jetronic used previously was replaced by the “standard-deck engine” which was already in use in the 500 E (W 124) and in the Saloons and Coupés of the S-Class (140 series).
Characteristic features of the new engine were its modified crankcase, whose deck height was now identical with that of the 4.2-litre unit, and the Bosch LH-Jetronic electronic injection system with mass airflow sensor. As in the V12 engine, full load enrichment was dispensed with here to reduce the pollutant emissions – a measure affecting not only the SL, but all other car models with V12 and V8 engines, too.
In the case of the 5.0-litre engine this meant an output reduction of 4.4 kW (6 bhp) to 235 kW (320 bhp), a loss which for all practical purposes was imperceptible in terms of vehicle performance. From June 1993 onwards the 500 SL was called the SL 500 owing to a reform of the nomenclature; this reversal of the model designations applied as a matter of principle to all Mercedes-Benz models.
Enter the twelve-cylinder engine
In October 1992, the dream of many a friend of the SL came true: three-and-a-half years after the presentation of the R 129 series, now it too became available with the 6.0-litre V12 engine which had already proven itself in the saloons and coupés of the 140-series S-Class.
To further reduce pollutant emissions the injection system was modified and full-load mixture enrichment dispensed with. In the 600 SL, June 1993 designated SL 600 and which was available from 1992 until 2001, the most powerful engine in the passenger car sales range delivered 290 kW (394 bhp) and made brilliant performance possible: at 6.1 seconds from a standstill to 100 km/h the acceleration was even better than that of the 500 SL; the top speed was likewise limited at 250 km/h.
The twelve-cylinder engine was the epitome of smoothness and turbine-like power delivery. Above all, its imperturbability in high speed regions and the impressive and simultaneously refined manner in which it reached top speed were characteristic of the 600 SL.
The sizeable additional charge of more than DM 60,000 over the 500 SL made its ownership a matter of prestige. But for that the new top model of the series was equipped as standard with a whole range of extras that could only be ordered at an additional charge in the 500 SL.
Apart from the ADS Adaptive Damping System with level control on both front and rear axles the basic equipment included, for example, cruise control, automatically dimming interior mirror, headlamp cleaning system, automatic climate control, leather appointments and seat heating. Externally, only the model designation badge and two “V12” badges in the vicinity of the air outlets behind the front wheel arches distinguished the 600 SL from its sister models.
The 1995 facelift brought improvements to the engines and transmissions of the SL 500 and SL 600 models. From September 1995, both featured a five-speed automatic transmission with torque converter lockup clutch, a completely new development that replaced the previous hydraulically-controlled transmission.
The heart of this technical wonder was an electronic transmission control that swiftly and automatically adapted shifting behaviour to every driving situation and permanently exchanged data with the electronic engine management. Apart from these forward-looking innovations the automatic transmission was appreciably more compact and lighter than comparable five-speed units.
The engines were reworked once more to cut fuel consumption and pollutant emissions further. For this purpose the 5.0-litre V8 engine was equipped with a modified crankshaft, optimised valve timing, lighter pistons, individual ignition coils for each cylinder as well as an improved electronic engine management system called Motronic ME 1.0.
Fewer changes were made to the design of the V12 power plant and merely concerned the configuration of the ignition coils and the electronic engine management system.
As a result of the various modifications to the engine and the use of the new automatic transmission, it was possible to reduce the fuel consumption of the SL 500 and SL 600 by ten per cent while maintaining the output unchanged. From June 1996 the new electronically-controlled automatic transmission also became available for the SL 280 and SL 320 six-cylinder models, as an optional extra for the 2.8-litre variant, and as standard equipment for the SL 320.
V-engines instead of in-line engines
The 1998 facelift ushered in the V-engine generation with six and eight cylinders, which replaced – in the SL, too – the six-cylinder in-line engines of the M 104 series and the V8 unit of series M 119. The engines featured three-valve-per-cylinder technology and dual ignition for better emission values. They were also characterised by lower production costs.
Outputs ranged from 150 kW (204 bhp) in the SL 280 (M 112, top speed 232 km/h, 0 to 100 km/h in 9.5 seconds) to 165 kW (224 bhp) in the SL 320 (M 112, 238 km/h, 8.4 seconds) to 225 kW (306 bhp) in the SL 500 (M 113, 250 km/h, 6.5 seconds). The top-of-the-range SL 600 continued to use the tried-and-tested twelve-cylinder engine (M 120) with an output of 290 kW (394 bhp). The SL 280 was now the only model of the series still available with a five-speed manual transmission; all sister models had automatic transmission as standard.
Those still unsatisfied with the output and prestige afforded by the eight-and twelve-cylinders could turn to AMG in Affalterbach, not far from Stuttgart. Since 1990 a cooperation agreement existed between AMG and Daimler-Benz AG. From 1 January 1999, AMG became a 51-per cent subsidiary of the then DaimlerChrysler AG and adopted the name Mercedes-AMG GmbH.
AMG offered power-hungry customers several alternatives. When the first vehicles developed on the basis of the cooperation agreement came out on the market in 1993, the first SL model was the SL 60 AMG (M 119, 6.0-litre V8, 280 kW/381 bhp), which was produced until 1998; a purely AMG version with the same engine had existed earlier, from 1991 to 1993, under the name AMG 500 SL 6.0.
Models SL 55 AMG (M 113, 5.5-litre V8, 260 kW/354 bhp, 1999 to 2001) and the top-of-the-range model with twelve-cylinder engine, the SL 73 AMG (M 120, 7.3-litre V12, 386 kW/525 bhp, 1999 to 2001), followed. The latter’s maximum torque of enormous 750 newton metres propelled the vehicle from 0 to 100 km/h in just 4.8 seconds.
The top speed of both cars was electronically limited to 250 km/h, but the limit could be neutralised on customer request. All power transmission components of the AMG models, from automatic transmission to rear axle, were adapted to the higher loads.
The AMG bodystyling package with fog lamps integrated in the bumper emphasised the terse dynamics of the sports car even more, without altering the clear lines of its design. The large AMG light-alloy wheels (diameter: 45.72 centimetres) added a further dash of unmistakable sportiness to the looks.
The special models of the R 129 series
Special SL models became available for the first time in the R 129 series. Extended and modified appointments distinguished them from the series-produced cars. This made them exclusive, offered a price advantage, and boosted SL sales at the same time. Between 1995 and 2001 there were 17 special series built in differing numbers, from ten to 1515 units.
In 1995 the “Special Edition” debuted with a production run of 630 units. It was available as SL 280, SL 320 and SL 500. Its distinguishing features included an exterior finished in brilliant silver, combined with red soft-top fabric.
The same year the “Mille Miglia” special series was released, with VIP and escort vehicles of the Mille Miglia Storica in Italy. There were a total of ten Mille Miglia units based on the Special Edition, but with further distinctive features such as an unobtrusive black-and-white chequered flag on the ornamental grilles of the front wings.
In 1998, another “Special Edition” arrived, available for all models except the SL 60 AMG; 500 units were built. Obsidian black was chosen as exterior paint finish; the leather seats were in designo red with black topstitching. The SL 280 was equipped with the five-speed automatic transmission as standard.
A further small VIP series was released on the occasion of the 1999 Mille Miglia Storica. It was based on the SL 55 AMG and ten units were built. A year later, the “SL Edition” stimulated the brand’s sports car sales; 708 units were built – the third-highest volume for an R 129 SL special series, and available as SL 320 and SL 500.
The “Final Edition”, dating from 2000 – 674 units were produced (all models with the exception of the SL 55 AMG and SL 73 AMG). They already heralded the approaching discontinuation of the series.
Special VIP models were again available that year: the “Formula One Edition” (20 units) based on the SL 500 on the occasion of the Indianapolis Formula One race, and 12 units of the “Mille Miglia” of 2000. In 2001, the last special “Mille Miglia” model in the R 129 series followed, with 13 units based on the SL 600 built this time.
Various special series were created upon the request of individual markets, for instance the “40th Anniversary Roadster Edition” (USA, 1997, 750 units, models SL 320 and SL 500, and 35 models AMG SL 60 Limited Edition), in celebration of the coming of the Mercedes-Benz 300 SL Roadster in 1957; “designo MB UK” (England, 1998, 150 units), “designo MB Japan” (Japan, 1998, 67 units), “designo Vintage Edition UK” (England, 2000, 49 units, models SL 280 and SL 320), “designo Heritage Edition UK” (England, 2000, 49 units, models SL 280 and SL 320), “Silver Arrow Edition USA” (USA, 2001, 1515 units of model SL 500, 100 units of model SL 600) and “Silver Arrow Edition UK” (England, 2001, 100 vehicles of model 500 SL).
The successor arrives
In July 2001, the Mercedes-Benz SL 500, the first model of the new SL series, the R 230 series, celebrated its world première. In the same month the last of a grand total of 204,940 units of the R 129 series rolled off the assembly line at the Bremen plant.
In terms of overall volume the first SL manufactured in Bremen was not quite as successful as its predecessor from the R 107 series (237,287 units); but if average annual production is compared, the R 129 series with some 16,500 units is very clearly in the lead.
The most successful model of this series was the five-litre variant equipped with the four-valve V8 engine M 119, of which a total of 79,827 were produced from 1988 to 1998. The rarest variant by far is the SL 280 with V6 engine, which served as entry-level model for the series from 1997 and rolled off the assembly line only 1704 times.
The R 129 series in the press
Shortly after the première of the Mercedes-Benz SL 500 “auto motor und sport”, Germany, No. 16/1989, wrote: “Altogether the new SL cannot be topped for passive safety by any sports car.
Apart from its sophisticated body structure and the optionally available driver and front passenger airbags, the automatically extending roll-over bar dispels fear of overturning – though a little concern remains, of course, because ‘auto motor und sport’ did not confront the function with the worst-case scenario.”
The American motor magazine “Road & Track”, No. 3/1993, tested the twelve-cylinder model Mercedes-Benz 600 SL: “Drive the 600 SL, however, and the change is dramatic. Although the 500 SL has everything we expect from a Mercedes (a 0-60 mph time of 6.4 seconds, fine handling and safety), the V12 just adds another dimension to this luxury sports car.
Some of that is pure power. Time to 60 mph – by our watch – drops another 0.4 sec., but what impresses most is all that torque lying in wait when you kick the 4-speed down a gear or two. Add the matter of smoothness – the smoothness of power that builds strongly rather than erupts, and the aural smoothness of the engine’s hum in the background, even at full throttle.”
In a test report “auto motor und sport”, Germany, No. 16/1998, wrote about the Mercedes-Benz SL 500: “For nine years the Mercedes SL 500 has embodied a highly cultivated blend of performance, safety and comfort. The standard automatic transmission and the perfected coexistence of two roofs are a part of this philosophy.”
Technical highlights of the Mercedes-Benz SL, R 129 series
- Automatic roll-over bars (deployment in 0.3 seconds)
- High-strength integral seats
- Drag coefficient cd = 0.32 (with hard top)
- Fully-automatic electrohydraulic folding top
- A world première: the draught-stop
- ADS Adaptive Damping System (optional)
- Fixed-calliper disc brakes
- First twelve-cylinder engine in an SL (1992)
- ESP® Electronic Stability Program (1995)
- BAS Brake Assist (1996)
- Cruise control down to speeds of 30 km/h (1996)
|Model||Internaldesignation||Production period: |
pre-production seriesto end
|Number of units|
|SL 280||R 129 E 28||1993-1998||10,319|
|SL 280*||R 129 E 28||1997-2001||1,704|
|300 SL||R 129 E 30||1988-1993||12,020|
|300 SL-24||R 129 E 30||1988-1993||26,984|
|SL 320||R 129 E 32||1993-1998||32.223|
|SL 320*||R 129 E 32||1997-2001||7,070|
|500 SL/SL 500||R 129 E 50||1988-1998||79,827|
|500 SL**||R 129 E 50||1997-2001||23,704|
|600 SL/SL 600||R 129 E 60||1991-2001||11,089|
|SL 55 AMG||R 129 E 55||1999-2001||***|
|SL 60 AMG||R 129 E 60||1993-1998||***|
|SL 73 AMG||R 129 E 73||1999-2001||***|
* With V6 engine.
** With M 113 engine.
*** Not registered separately.
Open the way for the vario-roof: Mercedes-Benz SL, R 230 series (2001-2012)
- Open-top car and coupé in one – the roof folds in 16 seconds
- Equipped with the most advanced dynamic handling systems
- Lightweight body with a high proportion of aluminium
The R 230-series SL was presented to the press in July 2001 at Deichtorhallen in Hamburg. Owing to a combination of advanced electronic chassis systems which was unique in the world at the time, the R 230 offered an outstanding driving experience coupled with highest levels of operating safety and so set trends for sports cars and car building in general.
At market launch, the first model available was the Mercedes-Benz SL 500 with an output of 225 kW (305 bhp). In autumn 2001, it was joined by the SL 55 AMG with a supercharged V8 engine and 350 kW (476 bhp). In 2002, the SL 350, featuring a 180 kW (245 bhp) 3.7-litre V6 engine, followed, and finally in January 2003 Mercedes-Benz introduced the SL 600 with the powerful 368 kW (500 bhp) 5.5-litre V12 biturbo engine as its new flagship model.
The extensive standard equipment of the SL included, for example, leather-upholstered integral seats plus memory function for the electric seat and steering wheel adjustment (additionally stored in the electronic ignition key); multifunction steering wheel, automatic climate control and stereo car radio.
As optional extras, innovative assistance systems like the DISTRONIC proximity control system, the TELEAID automatic emergency call system, the COMAND control and display system or an electronic tyre pressure monitoring system were available.
Leather, fine wood and aluminium are the materials used to create the typical exclusivity and perceived value of the SL. There was a choice of two types of leather, four high-quality trim variants and five appointment colours. Matt-finished chrome framed the four individual, classic chronometer-style instruments on the dashboard and was also to be found in other details of the interior.
The design combines tradition and future
The design of the R 230 series blends tradition and future through distinctive details. For instance, the air intakes in the front wings take up a typical feature of the 300 SL from the 1950s. The thin, wing-like segments on these side air intakes – called fins by experts – also are a reminiscence. The designers use this stylistic element additionally to give a sporty touch to the grilles of the openings on the bonnet.
The horizontally elongated radiator grille has always been an unmistakable feature of the SL. The R 230 series took up this tradition, but showed it in an up-to-date interpretation, thrusting a louvred radiator grille with a flatter slope than previously into the wind.
This, in combination with the more pronounced wedge shape of the body, made the front end appear very dynamic and powerful. The four louvres surrounded the Mercedes star, which in its accustomed size and position clearly indicated the brand to which the two-seater belonged.
These typical traditional SL features harmonised with the new elements, the headlamps, for example: on each side two of the familiar four “eyes” merged into one without giving up their basic oval shape. The up-to-date clear-lens look effectively enhanced the standard bi-xenon headlamps and gave an additional touch of brilliance to the front-end design.
The long bonnet took up the curves of the headlamps and carried them towards the rear in a terse arch. The design of the muscular wings also evolved from this ensemble. The soft lines of the bonnet and wings merged smoothly into the taut lines that gave structure to the sides of the body at the shoulderline.
Another line developed in the lower part of the wings from the verve generated by the side air intakes. It gave a formal hold to the large, quiescent surfaces of the doors, creating a visual bond with the rear end. The steeply raked windscreen emphasised the sports car character, accentuating its low, wedge-shaped silhouette.
16 seconds of roof acrobatics
Unlike its predecessors the R 230-series SL always carries its hardtop with it. The integration of the SL’s steel vario-roof into the car’s flowing lines is proof of the car’s high design quality.
At the push of a button, or via remote control, the roof can be opened or closed within 16 seconds. An extremely complex swivelling mechanism ensures that the three roof components disappear into the upper part of the boot in a space-saving way.
Underneath it, 235 litres of luggage space are available. With the top up, the vehicle offers 317 litres of space, including the luggage box in the spare wheel recess: that amounts to 52 litres more than the previous model. Since mid-2002, a glass sunroof variant is also available.
Further features underscored the impression of dynamism and elegance created by the R 230 series, for example the body with the powerfully shaped front apron, the muscular curves and the pronounced wedge shape, but also stylistic elements like the distinctive outline of the side skirts, the wide wheels (diameter: 43.18 centimetres) or the oval tailpipes of the exhaust system.
All body parts – from door handle to bumper – were painted the colour of the car body so that from a formal viewpoint and in terms of its colour the sports car appeared cast in one piece. This also applied to the rear end, characterised by large, triangular-shaped tail lights.
Here again instead of a play of colours, there was elegant consistency: the tail light lenses were a uniform red – special filters in front of the reflectors ensured that the turn indicators still appeared yellow and the reversing light white.
SBC™ Sensotronic Brake Control
The technical innovations of the R 230 series included the Sensotronic Brake Control SBC™ electrohydraulic braking system, which had its première in this series. It operated in conjunction with the ESP® Electronic Stability Program and the Active Body Control ABC active suspension system, which minimises body movements and any tendency to skid when cornering and braking.
Sensotronic Brake Control SBC™ was also a gateway to the world of future “by wire” systems that no longer transmit the driver’s commands mechanically or hydraulically, but electronically – by cable. The most important performance characteristics of SBC™ include extremely dynamic brake pressure build-up and a reliable “feel” for driver and vehicle behaviour thanks to sophisticated sensor technology.
For example, the system interprets a rapid shifting of the driver’s foot from the accelerator to the brake pedal as an emergency situation, automatically increases the pressure in the brake lines and simultaneously positions the brake pads on the brake discs so that they can grab the disc without delay and with full force when the driver depresses the brake pedal.
Thanks to this, the stopping distance is three per cent shorter in an emergency stop. In addition, thanks to variable brake force distribution, SBC™ affords more safety when braking on bends or on difficult surfaces, depending on wheel contact force and slip. Owing to greater dynamics and precision SBC™ also enhances the performance of the BAS Brake Assist and the ESP® Electronic Stability Program.
This package of highly efficient electronic control systems initiated a revolutionary trend in automobile manufacture in the area of chassis, handling safety and driving dynamics.
Suspension with ABC Active Body Control
These systems are supported by wheel suspensions which react sensitively in conjunction with the ABC Active Body Control. At the front a state-of-the-art four-link system ensures optimal road roar and tyre vibration characteristics, precise wheel location and steering.
The lower elements of the front axle, the steering gear of the rack-and-pinion steering, and the engine mounts are connected with an aluminium frame-type integral support which also celebrated its première in the new SL.
In the SL of the R 230 series, the multi-link independent rear suspension, still unsurpassed for wheel location, is made entirely of aluminium for the first time, including wheel carriers and sub-frame. To improve the oversteer/understeer characteristics even more, the axle geometry was modified in detail.
Ever since the “Pagoda” at the latest, the abbreviation SL has been synonymous with pioneering achievements in the areas of active and passive safety in open-top sports cars. With an entirely new, comprehensive concept the R 230-series SL clearly outstrips the previous safety standards to make it a model in the area of vehicle safety in particular for sports cars.
The concept makes allowance for all aspects of active and passive vehicle safety – from accident avoidance with the aid of electronic handling dynamics systems like SBC™, Active Body Control ABC, Brake Assist BAS, acceleration skid control ASR, or ESP®, to the structural integrity of the body with a high level of passenger cell rigidity in every conceivable type of accident.
Some of the things contributing to occupant protection together with the high-strength body structure: two-stage airbags for driver and front passenger, new head/thorax bags in the doors, newly developed integral seats, high-performance belt tensioners, belt force limiters, or the sensor-controlled roll-over bar, which goes into action, whether the vario-roof is open or closed.
In the event of an accident, the TELEAID automatic emergency call system (optional extra) developed by Mercedes-Benz ensures that emergency services and police are automatically alarmed and guided to the accident scene by satellite navigation.
Safety development between rating tests and reality
The R 230-series SL has passed the most rigorous crash tests such as an offset frontal impact at 64 km/h or the 90-degree side collision at 50 km/h, both of which are included in the European NCAP (New Car Assessment Program) procedure and which make the highest demands on the vehicle structure, especially in the case of open-top cars.
The engineers devoted just as much attention to the aspect of ease of repair, which they investigated in frontal and rear impacts at a collision speed of 15 km/h in each case. The body structure of the SL affords the greatest possible safety to occupants and meets the objective of reasonably priced repair.
In a frontal or rear collision at speeds above 15 km/h, the bodyshell structure of the SL provides an exemplary high level of occupant protection thanks to many innovative details. Around 33 per cent of the bodyshell is made of high-strength sheet metal affording maximum resistance coupled with minimum material thickness.
All components crucial to crash safety and body stiffness are made from high-strength steel sheet. The fuel tank is made of sheet steel and is located in a protected position above the rear axle.
Fuel economy a high priority
Fuel economy in the R 230-series SL is a topic which runs like a thread through many chapters of the design specifications. The lightweight body plays a decisive role in achieving a favourable fuel economy in all the vehicle variants: bonnet, front wings, doors, boot lid, tank partition and other components are made from aluminium; in particular the 1.40 metre long bonnet is a remarkable lightweight component.
The sophisticated aerodynamics of the smooth body including underbody, designed to reduce drag, helps to save fuel as well as minimise noise. The drag coefficient value of 0.29 for the closed car is a very remarkable figure; in the previous R 129 (with hardtop) it was still 0.32. The open-top SL of the R 230 series has a cd of only 0.34 (R 129: cd = 0.40 with the side windows closed).
Debut with the SL 500
In summer 2001 the SL 500, featuring a 5-litre V8 engine (M 113) delivering 225 kW (306 bhp) and torque of 460 newton metres debuted first. It was one of the most powerful engines of its segment, did clearly better than the stringent EU 4 emission standards required, and accelerated the SL 500 from 0 to 100 km/ in 6.3 seconds.
The top speed was 250 km/h (electronically limited). The proven five-speed automatic transmission with electronic control, two shift programs and torque converter lockup clutch were standard equipment in the SL 500. A newly developed touch shift permitted very fast manual gear-changes.
In September 2001, the SL 55 AMG followed with its première at the IAA International Motor Show in Frankfurt on the Main. Equipped with a new V8 supercharged engine, it was the most powerful Mercedes-Benz passenger car at the time. The 5.5-litre power plant (M 113) developed 350 kW and delivered a maximum, constant torque of 700 newton metres from 2650 rpm to 4500 rpm.
The car spurted from 0 to 100 km/h in 4.7 seconds; its electronically-limited top speed was 250 km/h. The engine was combined with a five-speed automatic transmission including steering wheel gearshift buttons.
The AMG version was distinguishable on the outside from the SL 500 among other things by bumpers with an even more powerful styling, distinctively shaped side skirts, dark-tinted tail lights, exclusive multi-spoke wheels (diameter: 45.72 centimetres) and four chrome-plated exhaust pipes.
In the interior, the more firmly upholstered integral seats with a special perforation and coloured topstitching, high-quality aluminium trim elements with a sand-cast look, and dashboard instruments with light dials, silver-coloured symbol discs and red needles emphasised the character of this sports car.
In 2002, the SL 350 followed, with a 180 kW (245 bhp) 3.7-litre V6 engine (M 112). It accelerated the car in 7.2 seconds from 0 to 100 km/h and achieved an electronically limited top speed of 250 km/h. It featured SEQUENTRONIC automated six-speed manual transmission as standard, operated via two shift paddles on the steering wheel. The electronically-controlled five-speed automatic transmission with touch shift was available as an optional extra.
A V12 engine in the flagship model
In January 2003, Mercedes-Benz presented the SL 600 with a 368 kW (500 bhp) 5.5-litre V12 biturbo engine (M 275) as new flagship of the series. It produced a tremendous torque of 800 newton metres, available already at 1800 rpm and constant up to 3600 rpm.
The newly-developed Mercedes-Benz twelve-cylinder engine with two turbochargers and air-to-water intercooler, three-valve-per-cylinder technology, alternating-current twin-spark ignition and other high-tech innovations is one of the most advanced passenger car engines in the world. It affords effortless superiority in any driving situation.
The SL 600 needed only 4.7 seconds to go from 0 to 100 km/h. Its top speed was electronically limited to 250 km/h. From the outside the SL 600 can be recognised by a radiator grille with discreet chrome inlays, silver-painted brake callipers, V12 emblems on the side air intakes, bi-xenon headlamps and exclusive light-alloy wheels. The front wheels have tyres of size 255/40 R 18, the rear wheels tyres of size 285/35 R 18.
Only 12 units: SL 350 “Mille Miglia Edition 2003”
Based on the SL 350, in June 2003 Mercedes-Benz presented the “Mille Miglia Edition 2003” special model to commemorate the legendary road race.
Only 12 of these were built. They were painted in a special “Silver Arrow” metallic finish and had matt-finished aluminium shoulderline trim strips, beautifully designed light-alloy wheels (diameter: 45.72 centimetres), wide-base tyres of size 255/40 ZR 18 (front) and 285/35 ZR 18 (rear) and “Mille Miglia” badges in the air outlet grilles of the front wings and on the boot lid.
The vario-roof of the special model was made of glass and gave the passengers a panoramic view. The special features in the interior included two-tone nappa leather appointments: the seats were in “classic red”, an accent colour already used in the legendary SL sports cars of the 1950s.
The roof was lined with soft Alcantara, and the trim elements on the centre console and the doors were aluminium with a matt-finished surface. With the aid of a new laser technique the designers worked the “Mille Miglia” logo and even the course of the thousand-mile race into the leather covers of the head restraints.
Other standard equipment items on the special model included the control and display system COMAND, the parking assist PARKTRONIC, multicontour backrests, CD changer and sound system. The V6 engine of the special model was combined with a five-speed automatic transmission as standard.
A special model on the 50th birthday
In 2004, Mercedes-Benz celebrated the appearance of the 300 SL in 1954 with the special model “Edition 50”, available as SL 350 and SL 500 in a series limited to a total of 550 units. The visual highlights included a matt silver-painted radiator grille with chrome trim strips, light-alloy wheels (diameter: 45.72 centimetres) in turbine design, shoulderline trim strips in a high-sheen finish, a draught-stop frame with high-sheen finish and darkened tail lights.
In the interior, the instrument cluster was trimmed with a leather/Alcantara combination. The seats, luxury climatised seats with multicontour function as standard, had nappa leather covers; the head restraints showed a lasered “Edition 50” logo. The trim elements in the interior were made of a decorative new aluminium material or, alternatively, black ash wood.
Depending on personal taste, if desired the leather appointments also could be had in two-tone condor silver/black or single-tone designo black with topstitching in quartz. A comprehensive range of standard equipment was included: for example, the COMAND APS radio and navigation system with CD changer and surround sound system, but also bi-xenon headlamps with headlamp cleaning system and PARKTRONIC.
In 2004, the new top-of-the-range model, the SL AMG was launched. Powered by an AMG 6.0-litre V12 biturbo engine producing 450 kW (612 bhp) and a torque of 1000 newton metres, it was the mightiest production roadster in the world.
Impressive proof of the exceptional power of the AMG twelve-cylinder engine was the fact that it could accelerate from a standstill to 100 km/h in just 4.2 seconds. In 2004, the V12 biturbo engine won the “International Engine of the Year” award in the category “Best Performance Engine”.
2006: facelift for the R 230 series
Five years after its launch, Mercedes-Benz upgraded the SL. The 2006 Geneva Motor Show was chosen as debut event. Engines, drive system and suspension in particular were given a sportier tuning.
The V8 engine (M 273) of the SL 500 was a new design; it now had a displacement of 5.5 litres and developed an output of 285 kW (387 bhp). It accelerated from 0 to 100 km/h in just 5.4 seconds. In the USA the vehicle was sold as the SL 550.
The six-cylinder engine of the SL 350 was a new development, too. The 200 kW (272 bhp) V6 power plant (M 272) delivered around 11 per cent more output while enabling fuel savings of more than 1 litre per 100 kilometres. The combined NEDC consumption was 10.3 litres per 100 kilometres. The SL 350 accelerated from 0 to 100 km/h in 6.6 seconds, making it over half a second faster than the previous model.
At the top of the model range was the V12 biturbo engine of the SL 600. Its output rose to 380 kW; the maximum torque, to 830 newton metres. With the twelve-cylinder engine this SL sped from 0 to 100 km/h in just 4.5 seconds.
The V6 and V8 models of the facelifted SL-Class are equipped as standard by Mercedes-Benz with the 7G-TRONIC seven-speed automatic transmission. The actively regulated suspension system Active Body Control ABC (standard equipment for the SL 500 and SL 600, optionally available for the SL 350) was further improved. It now reduces body movements in dynamic handling situations by as much as 60 per cent versus the previous model.
The body design was discreetly updated to include new bumpers with three large openings for cooling air, a more pronounced wedge shape, and fog lamps with chromed trim rings. The radiator grille now had three louvres with chrome elements painted matt silver. New light-alloy wheels made for an impressive side view.
The horizontally-divided tail lights with red-and-white covers in clear-lens look made the muscular rear end of the SL appear even broader.
The interior was also redone showing, for example, leather upholstery with a softer grain, new interior colours, aluminium trim elements with a prism pattern, and metal door sills embossed with Mercedes-Benz lettering.
From spring 2007, for models SL 350 and SL 500 a Sports package has been available for 2,975 euros extra. It sets the tone in the interior with contrasting topstitching in silver, perforated leather and aluminium trim elements. The look is determined among other things by large five-spoke light-alloy wheels (diameter: 48.26 centimetres) behind which silver-painted brake callipers are visible.
Perforated brake discs at the rear conduce to excellent deceleration. The 7G-TRONIC Sport automatic transmission with shift paddles on the steering wheel is also included in the configuration. Furthermore, the distinctive visual features include darkened tail lights.
In 2008, a comprehensive package of refinements was then applied to the R 230 series. The proven vehicle range was retained but supplemented by the SL 280 (170 kW/231 bhp) with a 3.0-litre V6 engine (M 272), so that there are now two six-cylinder models; both engines are based on the same basic unit and have the same engine number.
Also available is the SL 63 AMG, whose naturally aspirated V8 engine (M 156) develops 386 kW (525 bhp); as transmission it has the AMG Speedshift MCT, featuring a so-called wet start-up clutch instead of a torque converter.
The most conspicuous element of the model refinement package is the new front design: it adapts the SL to the brand’s current car design and focuses attention on a broad and thus very dominant radiator grille. It enhances the powerful look of the SL face, which appears surprisingly new but at the same time very familiar. Powerdomes on the bonnet enhance the vehicle’s strong visual impression. At the rear a newly designed diffusor-look bumper creates associations with racing.
The list of further refinements for the facelifted SL-Class is long. The technical innovations now include the optional Direct-Steer system, the Intelligent Light System with five light functions adapted to typical driving situations, and the AIRSCARF® neck-level heating invented by Mercedes-Benz, which can extend the open-top driving season into the cooler time of the year.
Exclusive high-performance coupé for the highly discerning
In November 2008, Mercedes-Benz presented the SL 65 AMG Black Series as an exclusive top-of-the-line model of the R 230 series. This high-performance coupé was developed in the AMG PERFORMANCE STUDIO and offered thoroughbred motorsport engineering.
The AMG 6.0-litre V12 biturbo engine delivered 493 kW (670 bhp) and 1000 newton metres of torque. As comparison: the SL 65 AMG, on which this top model was based, was powered by an AMG 6.0-litre V12 biturbo engine with an output of 450 kW (612 bhp). The SL 65 AMG Black Series could accelerate from a standstill to 100 km/h in 3.8 seconds, reaching a speed of 200 km/h in just 11.0 seconds on its way to its top speed of 320 km/h (electronically limited).
Meanwhile, the SL 63 AMG was a sensation on the world’s most famed racetracks: in the 2008 and 2009 Formula 1 seasons the car acted as official F1™ Safety Car. A newly-developed AMG sports exhaust system with a larger diameter and special rear silencers enabled the AMG high-rev naturally-aspirated engine to breathe with even greater freedom – and sound even sportier.
The AMG SPEEDSHIFT MCT 7-speed sports transmission provided sheer driving dynamism with steering wheel gearshift paddles enabling gear changes in 100 milliseconds.
A specially-developed coil suspension enabled optimum racetrack performance, allowing an individual suspension set-up for each specific track. Perfect traction, no matter what the weather conditions, was guaranteed by the combination of three-stage ESP® and a rear-axle differential with a 30-per cent blocking effect.
Larger-dimensioned and additional coolers for engine and transmission oil, coolant water and power steering ensured absolute reliability despite even tropical outside temperatures.
The R 230 series carried on the extraordinarily successful history of the Mercedes-Benz SL in the 21st century. A total of 170,000 customers have chosen one of the sports cars assembled at the Bremen facilities. In the spring of 2012, the new SL, of the R 231 series will see its market launch, representing the next generation of these SL production sports cars.
The R 230 series in the press
Regarding the Mercedes-Benz SL of the R 230 series, “auto motor und sport”, Germany, No. 12/2004, noted in a test report on the SL 500: “Lots of comfort, lots of safety, solid design, a pinch of sportiness, horsepower à la carte, plenty of fresh air and, as of most recently, a hardtop in the boot – this rare blend secures the two-seater a special position that makes it virtually unrivalled.”
“Autorevue”, Austria, No. 7/2008, described the stages of open-top driving in a Mercedes-Benz SL 350 in these words: “Progressive climate stages on a cool evening: first you raise the front and rear side windows, then you ask the passenger to put up the draught-stop.
Then you might switch off the seat ventilation and switch on the seat heater. The air conditioner radiates basic warmth. The Airscarf – that seductive neck-level heating system that we miss on the sofa in our living room – follows, in three heat levels. Last stage is the big roof number, amazingly graceful. And everything’s just fine.”
Shortly after the debut of the Mercedes-Benz SL 65 AMG Black Series “Road & Track”, USA, No. 1/2009, wrote: “Will anyone buy an SL 65 AMG Black Series for street use? Probably not. But for those few who might, the car is quite civilized on the road.
The ride is firm, but not overly so. To truly appreciate the incredible prowess of the SL Black Series, take the car to the track. Its sheer power and speed, together with confidence-inspiring handling, make it one of the most satisfying supercars in the world.”
Technical highlights of the Mercedes-Benz SL, R 230 series
- Vario-roof with sophisticated folding mechanism and a folding time of 16 seconds
- Roll-over bar retains its full functionality even with the vario-roof closed
- Electrohydraulically controlled SBC™ Sensotronic Brake Control brake system
- Suspension with ABC Active Body Control
- Innovative head-thorax airbags in the doors
- Drag coefficient cd = 0.29 (with closed roof)
- Use of lightweight components for optimum fuel economy