One of the most successful roadsters ever entered its second generation in March 2004: Mercedes-Benz presented the new SLK Roadster from model series 171 at the Geneva Motor Show.
At first glance, the more powerful lines of the exterior appearance are striking. Typical roadster features, such as the long bonnet, the flat windscreen, wide doors and extremely short overhangs at the front and rear, were emphasised even more strongly in the 4.08 metre long SLK than in its predecessor. This was achieved, among other things, by extending the wheelbase by 30 mm, lengthening the body by 72 mm with a significantly swept-back front and rear section, and giving the overall silhouette an even more wedge-shaped design. Carefully crafted details such as the striking front end and the wing profiles in the radiator grille anchored the design language of the SLK in the great sports car tradition of Mercedes-Benz.
The vehicle flanks were characterised by wide flared wings and 16-inch wheels. At the rear, a new integral rear apron, two oval exhaust tailpipes with chrome trims and striking tail lamps lights dominated the picture.
An innovation that was not only visually appealing but also relevant in terms of safety was the introduction of newly developed main headlamps using projection technology, which replaced the previous reflection headlamps. This resulted in wider and more even illumination of the road and a greater range for the dipped beam. Front fog lamps fitted with halogen bulbs were also part of the standard equipment. They were located in the bumper cover and offered a new cornering light function in conjunction with the optional bi-xenon headlamps. State-of-the-art technology was also used for the tail lamps: A total of 32 LEDs were responsible for the brake and tail lights. The light field generated here extended across the entire width of the tail lamp and also offered a significantly higher light intensity.
In keeping with the type of vehicle, the interior design had a sporty, technical look and emphasised its independent character. The colour contrast of silver-coloured controls and black-painted surfaces on the instrument panel, steering wheel, centre console and tunnel trim was visually striking. This also applied to the two large dial-type gauges, each of which was enclosed by a silver-painted, cut tube and an additional black glare shield.
For the first time, the SLK Roadster was available with the optional COMAND APS control and display system, which featured a modern TFT colour display with a screen diagonal of 6.5 inches and also included a DVD player. Among other things, the COMAND screen displayed SMS text messages, which could also be answered using the device.
The selection of available paint colours was newly compiled and adapted to contemporary tastes. In 1996, when the first version of the Roadster came onto the market, bold colours were the order of the day, but now the trend was towards more subtle colours. The largest selection in this respect was in conjunction with the leather interior. In this case, a palette of six interior colours was available: black, universe blue, Orient beige, dusky red, alpaca grey and, with the exclusive nappa leather option, tobacco brown. Together with the twelve available exterior colours, this offered a wide range of options for customising the preferred colour scheme.
The Roadster body had benefited not only visually, but also technically from targeted further development – for example through increased basic rigidity and an improved drag coefficient of cd 0.32 to 0.34, depending on the model. The basis for this were aerodynamic detail measures on the underbody panelling, the wheel spoiler and the spoiler lip on the boot lid. A side effect of the optimised aerodynamics, apart from its positive effects on fuel consumption, was above all improved driving stability at high speeds and when braking.
The innovative vario-roof, with which the first SLK set a new trend in 1996, was also further perfected. It now opened and closed in just 22 seconds and took up less space in the boot than before thanks to a new folding kinematic system with a rotating rear window: When open, the load volume according to the usual measuring method was now 208 litres – 63 litres more than the previous model. For the first time, the vario-roof could also be operated by remote control in the vehicle key.
The Mercedes-Benz developers' typical drive for perfection was also reflected in the innovative AIRSCARF headroom heating system. The innovative heating system, which made its debut in the new SLK as an optional extra, was housed in the seat backrests. At the touch of a button, air-conditioned air flowed out of special ventilation openings in the headrests, warming the passengers' neck and head areas during the journey – like a scarf made of air. This world first adjusted the fan speed in such a way that the best possible hot air distribution was achieved under all conditions. This adaptive control was active up to a driving speed of 120 km/h, after which the system worked with a constant setting. Alternatively, the power of the AIRSCARF system could also be regulated individually by hand in three stages.
As it was not possible to completely prevent air vortices from forming behind the two seats when the vario-roof was open, which caused an unpleasant suction effect for some passengers, a wind blocker was fitted as standard. Initially, this was a simple textile mesh fabric that was pulled over the two roll bars and fastened there with snap fasteners. Shortly after the market launch of the new model generation, this somewhat provisional solution was replaced by an optionally available wind deflector system consisting of three elements, which consisted of a transparent acrylic glass panel positioned between the roll bars and mesh-covered plastic frames that were inserted into the opening of the roll bars.
Air conditioning, called THERMATIC, was available as an option for the entry-level model with a four-cylinder engine. It came as standard in the six-cylinder-engined SLK 350 and the SLK 55 AMG. The THERMOTRONIC automatic climate control system, which was available as an option for the latter two models and could be controlled separately for the two passengers, was even more highly specified with solar and air quality sensors.
The new SLK-Class also offered further comfort benefits in terms of aeroacoustics: With the vario-roof closed, the interior noise level was on a par with a coupé, and because the folding hard top had better insulating properties than a soft top, it was up to 6 decibels quieter in the interior of an SLK at 140 km/h than in a comparable soft-top roadster – in terms of acoustic perception, this was equivalent to halving the noise level.
In principle, the slightly larger dimensions of the body compared to the previous generation benefited passenger comfort. In detail, the wheelbase was increased by 30 mm and the vehicle length by 72 mm, while the width was 65 mm wider and the vehicle height 20 mm higher. The sports seats, which were suitable for long journeys and whose backrests could be folded forwards, now had a greater fore/aft adjustment range.
In addition to driver and front passenger airbags, the new models had the innovative head/thorax side airbags on board. They were housed in the backrests of the front seats and protected the head and chest area. In addition, there was a rollover sensor which, if necessary, also sent its data to the central control unit of the restraint systems, whereupon the belt tensioners and the head/thorax airbags in the SLK seats were activated both with the vario-roof open and closed.
The range of drive units available at market launch initially comprised three engines – all petrol – covering a power spectrum from 120 kW/163 hp to 265 kW/360 hp. For the first time in this vehicle class, this included a V8 engine from AMG. However, it all started with the 120 kW/163 hp 1.8-litre four-cylinder engine from the M 271 engine series, which was fitted with a mechanical supercharger and used in the SLK 200 KOMPRESSOR. The engine was new in the SLK R 171 model series and belonged to the most modern generation of four-cylinder engines, which, with a package of measures called TWINPULSE, brought further progress in terms of power, torque, smooth running and fuel consumption. TWINPULSE combined various technologies such as supercharging, balance shafts, intercooling, four-valve technology and variably adjustable camshafts to create an efficiency-enhanced overall package that combined high power output with low fuel consumption and reduced emissions. The average standard fuel consumption for the SLK 200 KOMPRESSOR was 8.7 to 9.1 litres per 100 kilometres.
The 3.5-litre V6 in the SLK 350 was a completely new development. The engine came from the recently presented M 272 engine series and made its debut in the Roadster. Closely related to the V8 petrol engine of the M 273 series, the six-cylinder engine also had a 90° bank angle. In the 3.5-litre version, the engine produced 200 kW/272 hp and a maximum torque of 350 Nm, which was available from 2400 rpm and was constant linear curve up to 5000 rpm. The driving performance resulting from this volume of power definitely equalled that of a high-ranking sports car: The top speed was limited to 250 km/h, and the acceleration sprint to 100 km/h took no more than 5.6 seconds.
Power was transmitted via a manual 6-speed transmission as standard; an automatic transmission was available as an option. Depending on the transmission, the average standard consumption of the SLK 350 was 10.1 to 10.6 litres per 100 kilometres. Despite a 25 % increase in performance, it was therefore around 6 % or 3 % more economical than the comparable predecessor model, the most recently offered SLK 320 from the R 170 series.
For those who preferred maximum gearshift comfort to the particularly active combination of a powerful drive unit and 6-speed manual transmission, the SLK-Class offered another new feature: The world's first 7-speed automatic transmission 7G-TRONIC was available as an option for the SLK 350. Due to the larger number of gear ranges available, its main advantages were more powerful acceleration, faster intermediate sprints and favourable fuel consumption. The SLK 55 AMG was equipped with 7G-TRONIC as standard – under the additional designation SPEEDSHIFT with an even sportier gearshift strategy and shorter shift times. Both automatic transmissions could also be operated manually using shift buttons on the steering wheel. In addition to the manual drive program, the transmission modes "C" (Comfort) and "S" (Sport) were also available.
The sportily tuned suspension differed from the predecessor model with a newly developed three-link front suspension, rack-and-pinion steering and an even more powerful brake system. The rear axle was modified in detail and adapted to the larger track width. Depending on the model variant, 16, 17 or 18-inch light-alloy wheels were standard equipment on the new SLK-Class. A sports suspension with a lowered body was available on request.
For the market launch scheduled for the end of March 2004, gross list prices of 33,524.00 euros and 43,384.00 euros were set for the SLK 200 KOMPRESSOR and the SLK 350, respectively.
The V8 power unit of the SLK 55 AMG opened up new worlds of performance for the SLK-Class. With a displacement of exactly 5439 cm³, the power unit from the M 113 engine family delivered a powerful 265 kW/360 hp at 5750 rpm, realised a best torque value of 510 Nm at 4000 rpm and accelerated the Roadster from a standstill to 100 km/h in 4.9 seconds. The electronically limited top speed here was also 250 km/h.
Thanks to its high torque and the typical AMG V8 soundscape, the SLK 55 AMG gave its passengers a special driving experience. The 7G-TRONIC in the AMG SPEEDSHIFT specification could be operated either automatically using the selector lever of the sequential gearshift or manually using two shift buttons on the AMG sports steering wheel. The manual shift program "M" was specially designed for the high flexibility of the V8 engine: As the transmission always remained in the selected gear, there was neither an automatic downshift under full load and kickdown nor an upshift when the rev limit was reached.
On the suspension side, the AMG version was adapted to the available performance potential in many areas. Standard equipment included a specially tuned AMG sports suspension, the AMG High Performance braking system with internally ventilated and perforated brake discs in composite design and the newly developed Direct-Steer system. This package of measures guaranteed a high level of driving stability combined with pronounced agility.
Visually, the SLK 55 AMG emphasised its prominent position in the range with numerous striking styling elements. At the front of the vehicle, for example, these included the arrow-shaped front end with projection headlamps under clear-glass covers, round clear-glass fog lamps with chrome rings in the AMG-specific front apron with side air outlets through which the hot exhaust air from the engine oil cooler escaped, and a black-painted cross strut in the radiator grille.
In the side view, aerodynamically shaped longitudinal member panels and 18-inch AMG light-alloy wheels in a multi-spoke design, fitted with mixed 225/40 tyres at the front and 245/35 tyres at the rear, set visual accents. The rear was characterised by the AMG rear apron with black insert, the AMG sports exhaust system with two twin tailpipes, darkened glass covers on the tail lamps and third brake light, and the AMG spoiler lip on the boot lid. The latter reduced lift by up to 36 %.
The interior appearance of the performance roadster was dominated above all by the AMG sports seats upholstered in fine-grained nappa leather with a specific seat design; the door centre panels and armrests were also covered in the same material. Clearly pronounced side bolsters and Alcantara inserts in the shoulder area of the seats optimise lateral support when cornering. Other interior features of the AMG version included the height- and length-adjustable AMG sports steering wheel with gearshift buttons and the instrument cluster with its speedometer scale extending up to 320 km/h.
The SLK 55 AMG was initially available for a gross list price starting at 63,974.00 euros.
In early summer 2005, Mercedes-Benz launched another six-cylinder model in the R 171 Roadster series – the SLK 280. It significantly reduced the considerable performance gap that had previously existed between the SLK 200 KOMPRESSOR and the SLK 350. The new variant was also based on the 90° V6 from the M 272 engine family, but in this case the cylinder volume was limited to 2996 cm³ due to reduced bore and stroke dimensions. The engine was set to an output of 170 kW/231 hp, accelerated – manually shifted as standard – from 0 to 100 km/h in 6.3 seconds and reached a top speed of 250 km/h, which was also limited. In terms of its fuel consumption, which averaged a maximum of 9.9 litres per 100 km, the SLK 280 was positioned almost exactly between the four-cylinder entry-level model and the powerful 3.5-litre model.
This also applied with regard to the gross list price of 39,382.00 euros stated at the market launch of the new model version.
With the creation of the AMG Performance Studio in July 2006, Mercedes-AMG GmbH launched a new offensive to address individual customers. In addition to the AMG high-performance cars, which were available through the worldwide Mercedes-Benz sales organisation, the development and production of very special AMG vehicles in exclusive small quantities were now also on the agenda of the Mercedes-Benz racing and sports car brand based in Affalterbach. Subdivided into several product lines, the founder of the special model series of the same name made its debut in the same month as the first result of these new activities: the SLK 55 AMG Black Series.
This version emphasised the sporting talents of the eight-cylinder SLK in an emphatically purist form. Equipped with a permanently installed carbon roof, the performance version featured a version of the AMG 5.5-litre V8 engine with increased output of 294 kW/400 hp and 520 Nm torque, numerous lightweight components, AMG 19-inch forged wheels, AMG coil-over sports suspension and the AMG High Performance composite braking system. The dynamic limits of the highly specified Black Series model could only be fully explored on a closed racetrack. The gross sales price for the exclusive special model was initially set at 107,300.00 euros.
The AMG Performance Studio now also offered an optional component programme, with the help of which the regular SLK 55 AMG could be further enhanced in terms of driving dynamics and appearance. Among other things, exclusive wheel/tyre combinations, a special AMG Performance suspension and genuine carbon fibre trim parts were available, some of which were combined in package form.
A little later, Mercedes-Benz also made an optional sports package available for the four- and six-cylinder models, which further emphasised the Roadster's driving character. Among other things, it included a sports suspension with 18-inch alloy wheels and 225/40 (front) and 245/35 (rear) tyres as well as a particularly powerful brake system with enlarged and perforated discs on the front axle. The 10 mm lowered body, headlamps with dark edges and an AMG spoiler lip on the boot lid were further external features of the special equipment. In the interior, red seat belts and red topstitching on the door trims, seats, leather steering wheel and on the bellows of the leather-covered gear lever/selector lever caught the eye. In addition, red-edged floor mats and red pointers in the instrument cluster contrasted effectively with the black roof lining.
After Mercedes-Benz celebrated the tenth anniversary of the SLK-Class with the "Edition 10" show car at the Paris Motor Show in October 2006, the imminent series production of a similarly specified, limited-edition special model of the same name was announced just one month later. The Edition model, which was finally available from January 2007 in combination with a four or six-cylinder engine, was characterised above all by exclusive visual accents. These included, in particular, the new matt grey metallic paint finish called allanite grey magno, which was available on request, and the 17-inch 10-spoke light-alloy wheels in dark grey high-gloss Chrome Shadow finish with wide 225/45 (front) and 245/40 (rear) tyres. The scope of the special equipment also included dark-coloured tail lights and engraved wing badges with the stylised inscription "EditI0n".
In the interior, passengers in the "Edition 10" models were surrounded by a selection of fine materials. The seats, the armrest in the centre console and the gearshift or automatic gear selector lever were upholstered in black leather. The visual highlight was the silver-coloured support mats concealed beneath the seat cushion centre panels, which shimmered through the perforated leather and, like the silver-coloured topstitching on the seats, created a pleasing contrast.
The "Edition 10" equipment package, available for a total of 350 vehicles, had to be ordered separately and was available at gross list prices starting at 1,428.00 euros, depending on the engine. An additional 2,497.81 euros was charged for the exclusive metallic matt paint finish allanite grey MAGNO.
Until the end of 2007, when the facelift of the R 171 model series scheduled for this date came into effect, there were no further significant changes to the individual SLK versions, either in technical or visual terms. The production figures recorded for the first production cycle impressively demonstrated how enormously successful the second model generation was in establishing itself on the market. The only remaining four-cylinder-engined model in the range, the SLK 200 KOMPRESSOR, accounted for around 106,500 units in the production statistics alone. The SLK 350 took second place with almost 45,000 vehicles. The SLK 280, which was only available from mid-2005, took third place with over 35,000 units. Even the expensive AMG model achieved a very respectable result until the facelift at the end of 2007: More than 9,000 deliveries were recorded here.
In view of the fact that the SLK-Class was purely a niche vehicle, the number of units achieved in the R 171 model series spoke for itself. In the roadster segment, the new generation models also clearly outperformed all competitors.
