The second generation of one of the most exciting and successful sports cars on the market is ready to hit the streets: Mercedes-Benz presents the new SLK-Class. Even more alluring, more powerful and sportier than ever, the beguiling two-seater is due to celebrate its European market premiere in March 2004. Three dif-ferent engine variants are available for the new car, developing from 120 kW/163 hp to 265 kW/360 hp. The range includes - for the first time in this vehicle class - an eight-cylinder power unit from Mercedes-AMG. The V6 engine in the SLK 350, meanwhile, develops 200 kW/272 hp and delivers impressively dynamic driving pleasure.
Plus, Mercedes-Benz is presenting a world first, in the shape of the innovative AIRSCARF neck-level heating system. At the touch of a button AIRSCARF generates warm air, which flows out from the head restraints. This allows the SLK passengers to keep the roof down even when the outside temperatures drop and to enjoy the open-top roadster experience the whole year round. Automatic climate control, bi-xenon headlamps with cornering light function, COMAND APS and the unique seven-speed automatic transmission 7G-TRONIC are among the other technical innovations offered as options for the first time in the SLK-Class.
The new Mercedes Roadster replaces a successful first-generation model enjoyed by over 308,000 delighted owners since autumn 1996. The global number one in its market segment, it serves as a symbol for the new, dynamic brand image of Mercedes-Benz.
The second generation of the SLK-Class has an even sportier edge in terms of both its design and engineering and, with its powerful engines, newly developed chassis, direct steering and precise six-speed manual transmission, delivers an even more agile driving experience. The body is 72 millimetres longer and 65 millimetres wider than the outgoing model, providing the SLK’s passengers with more space and even greater comfort.
Design: sporty dynamism, with styling elements inspired by motorsport
The design of the car reflects the sporty and powerful character of the new SLK-Class. A long bonnet, flat windscreen, wide doors and a short rear represent typical roadster characteristics given extra emphasis by the new SLK. This extra forcefulness is underpinned by a 30-millimetre longer wheelbase, clear tapering of the front and rear ends and a wedge-shape silhouette.
A range of captivating details inspired by racing cars – such as the arrow-shaped nose, wing profiles in the radiator grille and the twin-tailpipe system – underline the origins of the SLK in a company which can point to an illustrious sports-car tradition.
The interior has also been completely redesigned and upgraded through the use of carefully selected materials. The design concept is distinguished by switches, buttons and trim elements with silver-coloured surfaces, which form a striking contrast to the dark tones of the dashboard. Plus, customers can choose from a range of six shades for the leather trim, or any one of twelve designo appointment colours.
The beautifully sculptured bodywork is also an achievement in terms of its technical prowess. The Cd value (0.32) is a good example, as are the rigidity of the body and the fuel tank capacity (70 litres). The Sin delfingen engineers have further optimised and perfected the technology behind the innovative varioroof, which marked the SLK out as a trendsetter on its arrival in 1996. The roof now opens and closes even more quickly and takes up even less space in the boot – thanks to the pivoting rear window. With the varioroof open, boot capacity stands at 208 litres according to the VDA method - 63 litres more than in the outgoing model. A further new feature now makes it possible to operate the varioroof by a remote control function in the car key (optional).
Safety: newly developed protection system with adaptive airbags
State-of-the-art construction processes, the increasingly large proportion of high-strength steel alloys (40 percent) and a host of other measures besides allow the new SLK-Class to leave the outgoing model in its slipstream. The occupant protection systems adjust their reactions according to the situation in hand. For example, adaptive airbags – which inflate in two stages in response to the severity of the accident – are making their debut in this model series.
The standard-fitted belt force limiters also work through two stages and adapt to the severity of the accident. In the event of a side impact, newly developed head/thorax airbags inflate to protect the head and upper body of the passengers. A special sensor also triggers the side airbags and both belt tensioners if the car rolls over. Robust steel tubes in the A-pillars and solid roll-over bars behind the seats offer additional protection in this type of accident.
Engines: up to 25 percent more power coupled with reduced fuel consumption
The range of engines available for the SLK-Class is also quite unique in this market segment. Here, Mercedes-Benz is the first manufacturer to respond to the desires of drivers with more sporting ambitions by adding an eight-cylinder powerplant to the mix. The V8 unit gives the SLK 55 AMG class-leading output (265 kW/360 hp), torque (510 Newton metres) and acceleration (0-100 km/h: 4.9 seconds) figures. The top-of-the-line engine is linked up as standard with the newly developed seven-speed automatic transmission 7G-TRONIC, which the driver can choose to operate using steering-wheel gearshift buttons.
For the SLK 350, meanwhile, Mercedes-Benz has developed a new six-cylinder engine with around 25 percent more power (200 kW/272 hp) and 13 percent extra torque (350 Newton metres). The four-valve unit is one of the most powerful V6 engines in its displacement class and reinforces its sporting credentials with a pleasing, full-throated sound.
Peak torque is available as low down as 2400 rpm and remains constant up to 5000 rpm. This provides the key to powerful acceleration and impressive mid-range sprints. The SLK 350 reaches 100 km/h from a standstill in just 5.6 seconds (with 7G-TRONIC: 5.5 seconds) and accelerates from 60 to 120 km/h in 8.7 seconds (with 7G-TRONIC: 5.1 seconds).
For the first time, Mercedes-Benz is using variable intake and exhaust camshaft adjustment in the V6 engine. This boosts output and torque, whilst also helping to save fuel. A second intake manifold, tumble flaps in the intake ducts and intelligent heat management are further technical highlights of the new six-cylinder unit. When fitted with the seven-speed automatic transmission, the new SLK 350 burns 10.1 litres of premium unleaded petrol per 100 km (NEDC combined), making it some three percent more economical than the outgoing SLK six-cylinder variant with five-speed automatic transmission, despite its significantly deeper power reserves.
The 120-kW/163-hp engine under the bonnet of the SLK 200 KOMPRESSOR is also celebrating its premiere in this Mercedes model family. The new arrival is a member of the unique TWINPULSE generation of four-cylinder engines from Mercedes -Benz, which offer further advances in terms of output, torque, smoothness and fuel consumption. The TWINPULSE system brings together various technologies, such as a supercharger, balancer shafts, an intercooler, variably adjustable camshafts and four-valve technology. This high-tech package allows the SLK 200 KOMPRESSOR to burn eight percent less fuel than the outgoing engine with the same output. NEDC combined consumption stands at 8.7 litres per 100 kilometres.
The SLK 200 KOMPRESSOR and SLK 350 are fitted as standard with a six-speed manual transmission which stands out with its short and fast shift travel and impressive precision. The proven five-speed automatic transmission is available as an option for the four-cylinder engine, whilst customers can order the new V6 model with the seven-speed automatic transmission 7G-TRONIC. In keeping with the dynamic and agile character of the SLK-Class, the driver can also operate either automatic transmission using buttons on the steering wheel (optional) and select the gears manually.
The chassis for the new SLK has a sporty set-up and differs from the outgoing model with its newly developed three-link front suspension, rack-and-pinion steering and an even more effective braking system. Mercedes engineers have carried out detailed modifications to the multi-link independent rear suspension and adapted it to the larger track width. The new SLK-Class comes as standard with 16, 17 or 18-inch light-alloy wheels, depending on the model. Sports suspension with a lowered body is available as an option.
Comfort: new AIRSCARF system ensures even greater open-air driving pleasure
The new Mercedes-Benz SLK-Class is an open-top motoring enthusiast’s ticket to enjoying themselves more frequently, more of the time. Making its global debut, the AIRSCARF system allows you to open the varioroof in cooler weather and thus enjoy the roadster experience more often. AIRSCARF is an innovative heating system located in the seat backrests. At the touch of a button, heated air is directed out of special vents in the head restraints and acts like an invisible scarf to warm up the head and neck of the SLK passengers when out on the road.
Available as an option, this new development is unique to the new SLK. It works in three stages and is fitted with an electronic control unit which adjusts the neck-level heating according to the speed of the car and the outside temperature and regulates the blower speed in order to achieve optimum warm-air distribution in any situation.
The optional air conditioning system THERMATIC (standard in the SLK 350 and SLK 55 AMG) is another innovation designed to ensure the perfect on-board climate. For even more discerning customers, Mercedes-Benz has developed the luxury automatic climate control system THERMOTRONIC with built–in sun and pollutant sensors.
Entertainment and information are delivered to SLK passengers through the Audio 20 CD stereo system, Audio 50 APS with integrated colour display and navigation system or COMAND APS, which includes a DVD/CD player, colour screen and separate DVD drive for the navigation function. A surround-sound system with eleven speakers and 380-watt output is also available as an option in order to further optimise the in-car audio experience.
SLK-Class: two studies pave the way for a new roadster star
Against this historical backdrop, it seemed only logical some decades later to revisit these considerations: would it not perhaps be appropriate for the SL-Class models, now firmly established in their own right, to be joined by a younger brother? After all, in the mid-Nineties, Mercedes-Benz had launched an entirely new product initiative, to which a compact roadster could lend fresh emphasis by drawing attention to the sporting heart of the Mercedes-Benz brand.
An appropriate acronym for this newcomer was swiftly coined: SLK. These three letters form the German initials for three characteristic properties of this car: sporty, lightweight and [k]compact. Recalling as they do the great sporting successes of Mercedes-Benz back in the Twenties and Thirties, they have an almost mystical reso-nance.
In Turin in April 1994, roadster enthusiasts were able to gain a first glimpse of how Mercedes-Benz believed a compact modern roadster should look. A brilliant silver showstopper with a distinct aura of spartan sportiness sent the trade professionals into raptures. “We are exhibiting a forward-looking roadster study which delivers a unique synthesis of purist motoring pleasure with all the safety features for which Mercedes cars are renowned”, announced the famous car manufacturer from Stuttgart.
To find out just how seriously the people in charge at Mercedes-Benz were taking this SLK project in its earliest days, you need look no further than the Paris Motor Show held in September of the same year. Here the company unveiled its second study, this time with vario-roof and in the form of a customised version with blue paintwork, harmonising blue-tone leather and a range of luxury accessories such as automatic transmission, air-conditioning system, power windows, a stereo system and much more besides. This enabled Mercedes-Benz to demonstrate convincingly the breadth of appeal and the potential inherent in a compact roadster.
Then the automotive enthusiasts started to wait. Many viewed the SLK as a very aus-picious prospect indeed. Mercedes-Benz had done the unexpected and had demon-strated that a small and relatively inexpensive roadster was capable of offering a great deal of motoring pleasure while still being an absolutely serious and down-to-earth car in terms of safety and quality. This meant that the two roadster studies had already opened up a new market niche and the SLK had already assumed the status of a trendsetter even before it went into production.
By 1996 everything was in place: the production version of the new SLK-Class was launched at the Turin Motor Show. Especially high levels of interest were shown in the fully-lowering steel vario-roof which substantively backed up the SLK claim to being a car for all weathers. Using an intelligent electro-hydraulic system, the entire roof folds down into the boot in just 25 seconds leaving the owner free to roam under an open sky.
The SLK also fielded a convincing range of other qualities. Take safety for example: two fixed roll-over bars behind the seats protect occupants from injury if the car should overturn and, in conjunction with the exceptionally robust A-pillars, deliver a very high level of safety even when these Mercedes-Benz cars are driven with the top down. Board of Management member Professor Jürgen Hubbert summarised what distinguishes the SLK: “Its design is exciting, and it exudes an appealing charisma. In a car like this, the journey is an end in itself.”
Is this excessive praise? No, far from it: the trade press actually went even further with its accolades. “Auto, Motor und Sport” found that the “bright and breezy compact roadster” with its “muscular lines” made everyone’s “mouth water”. Then, prior to the September market launch, when Mercedes-Benz had to announce with regret that the 1997 production run was already sold out, the specialist journal judged this “to be really tough news.” It then went on appeasingly to state “this one is worth waiting for.”
Even the road manners of the compact roadster met with recognition: “As a coupé the SLK behaves just as impeccably as it does in roadster guise. The high standard of rigidity it exhibits exceeds even optimistic expectations. It steers responsively and demonstrates high precision on winding country roads.”
Engines from 136 to 354 hp
The sporting talent of the SLK will initially be unleashed by two engine variants: the SLK 200 is powered by a 2-litre four-cylinder engine with a power rating of 100 kW/136 hp. The SLK 230 KOMPRESSOR features a supercharged 2.3 litre engine, also a four-cylinder unit, delivering 142 kW/193 hp onto the road. In early 2000, the two-litre engine was also fitted with a belt-driven supercharger, boosting power to the rear axle to a new level of 120 kW/163 hp. The choice of engines was broadened by the arrival of two six-cylinder models, a 160 kW/218 hp unit for the SLK 320 and the 260 kW/354 hp powerhorse in the SLK 32 AMG.
Moreover, Mercedes-Benz substantially upgraded the level of equipment for its roadster and incorporated innovations such as the Electronic Stability Program (ESP®), a six-speed manual transmission and SPEEDTRONIC in its standard equipment package. In visual terms, a new design of bumper and side skirt gave the car an even more dynamic appearance. All the attachments and door handles were painted to match the vehicle body to enable the whole car to present an image of a unified whole in both colour and form. New tail lights, stainless steel trim on the exhaust tailpipe and a painted radiator grille gave the SLK design an even more commanding identity.
With its SLK-Class, Mercedes-Benz succeeded in developing a car which really exudes an air of freedom, independence and adventure. A car for the emotions. An attractive roadster with a strong character promising untrammelled joie de vivre to its owners. More than 40 international prizes and awards bear testament to the tremendous popularity of this compact roadster, a car recognised in its class as a real trendsetter and one whose technology, design and level of equipment satisfies the most demanding of aspirations:
- In 1996 Italian artists and art critics hailed the SLK as the “most beautiful car in the world”. The British “Car Magazine” praised the Mercedes roadster as the “Best technical concept” and “Bild am Sonntag” awarded it the “Golden Steering Wheel”.
- In 1997 alone, the SLK harvested no less than 20 international awards. These included the title Best of What’s New” from the American magazine “Popular Science” and the title “Import Car of The Year” from the Japanese automotive press.
- In 1998 the “American Marketing Association” declared the SLK to be the “Best New Product” and the readers of the German magazine “Auto, Motor und Sport” voted the Mercedes roadster the “Best Convertible”.
- n 1999, or almost three years since its market launch, the SLK was still winning highly prized titles: “Best Convertible”, “Best Gear 1999” and the German award of “Most Popular Convertible” to name but three.
Even the real optimists at Mercedes-Benz had not anticipated the incredibly high popularity rating of the SLK series. In the early days, the maximum annual production target was assumed to be in the region of 35,000 units, but even in 1997, almost 50,000 SLK models rolled off the assembly line. As a result, virtually one in three of all compact roadsters sold worldwide that year bore the letters SLK on the back. By the end of its time in production, more than 308,000 people had taken ownership of a new SLK Roadster.
The new SLK-Class aims to follow this successful lead, and production commences in early 2004. This new roadster will be even sportier, even more dynamic and will offer even greater levels of motoring pleasure. In doing so, it looks sure to satisfy the continually rising aspirations of drivers to own a car genuinely capable of inspiring the emotions.
The new SLK-Class reaps the benefits of the progress that has been made: the safety technology on board the sporty roadster is in line with the very latest findings from the field of accident research, and sets new benchmark standards for this vehicle segment.
The Mercedes concept centres around restraint systems capable of adapting to different types of collision. The result is a further decrease in the loads placed on occupants in the event of a severe collision, as well as optimisation of the protective functions triggered following more moderate collisions. It is in this key aspect that the new SLK Roadster differs noticeably from its predecessor, which was itself deemed to be one of the safest sports cars on the road. On the new model, both the driver and passenger airbags feature two-stage operation, as do the new two-seater’s belt force limiters. This means that the systems are deployed in such a way that they are able to offer the greatest possible protection for the situation at hand.
Restraint system: two-stage airbags and belt force limiters
The driver’s airbag is fitted with a two-stage gas generator: in the event of a minor impact at the front, the control unit only ignites the first stage and the airbag inflates more gently. Should the control unit detect a severe frontal collision, however, it deploys the second stage of the gas generator after a delay of some 5 to 15 milliseconds. As a result, the airbag inflates at a higher pressure to provide the driver with the level of protection required in a collision of this severity.
The airbag on the passenger side operates on precisely the same principle, as well as incorporating brand new technology which further improves the way in which the airbag inflates evenly to cover a wide area. In addition to this, the initial pressure increase of the two-stage generator is reduced meaning that the airbag inflates even more gently. This shows just how much consideration Mercedes engineers have given to the fact that children are often seated in the front passenger seat, where the newly developed airbag now offers them even more protection.
The belt force limiters, which make up part of the standard specification of the new SLK-Class, are also able to adapt to the severity of the collision. Should the control module detect a high impact load, it will reduce the restraining force acting on the belt strap after just a short time; as a result, more of the seat belt strap will be fed out and the airbag will be able to cushion the seat occupant more effectively.
Head/thorax airbag: new air cushion integrated into the seat backrest
Mercedes-Benz is also equipping the new SLK-Class as standard with the newly developed head/thorax sidebags which have already debuted in the top-of-the-range SL-Class sports cars. They are accommodated in the backrests of the seats where they are positioned between the sturdy magnesium frame and the cushion holder. Following a side impact, the head/thorax airbag transforms into an asymmetrically shaped cushion in a matter of just 30 milliseconds, with the top edge reaching high above the seat when the airbag is fully inflated. This reduces the risk of the occupant’s head colliding with either the side window or any objects that penetrate the interior of the vehicle, regardless of the occupant’s seating position.
The middle of the head/thorax airbag slides between occupant and door in the event of an impact from the side or the vehicle rolling over, so that the chest area is also cushioned.
Sensor system: upfront sensors enable quick detection of accident severity
The swift, adaptive response of the restraint system is made possible by a highly advanced sensor system. In the event of a head-on collision, fast response is taken care of by two extra upfront sensors. Their remote positioning on the radiator cross member in the front end of the SLK body enables them to detect the severity of a collision even earlier and with greater accuracy than the central crash sensor on the transmission tunnel. The information from the upfront sensors is used by the electronic control module to shorten the time that elapses between the moment of impact and the deployment of the belt tensioners, to adapt the operation of the belt force limiters to the severity of the collision and to trigger the airbags both earlier and in two stages, depending on the situation.
Rapid activation of the head/thorax airbags in the seat backrests is the task of two additional satellite sensors positioned on the outer edges of the bodyshell’s seat cross members which work together with the central crash sensor.
Quite apart from this, the new SLK-Class is also equipped as standard by Mercedes-Benz with a roll-over sensor, which reliably recognises this type of accident and relays its data to the restraint systems’ central control module. In response to this signal, the micro-computer activates the belt tensioners and the head/thorax sidebags in the SLK seats, regardless of whether the vario-roof is open or closed.
Still to be found on the list of standard equipment for the SLK-Class are a sensor pad in the passenger seat which detects whether the seat is occupied, as well as the in-house-developed automatic child seat recognition facility. The child seat recognition facility comprises special aerials in the seat cushion which exchange data with the transponders that are fitted in the base of child seats from the Mercedes accessories range. Using this data, the central control module is capable of detecting when a child seat has been fitted, causing it to deactivate the airbag on the passenger side, as deployment of the airbag could otherwise increase the risk of injury.
Corrosion protection: fully galvanised body
To equip the SLK with long-term corrosion protection, the entire bodyshell is galvanised. In addition, some of the metal panels are treated to an additional organic coating on both sides which also contains rust-inhibiting zinc pigments. All the most vulnerable structural sections of the bodyshell are also protected with a cavity-fill preserving agent. A large area of the underbody is made from plastic so Mercedes engineers were able to dispense with conventional PVC underseal, a potential environmental hazard. The underbody trim panelling protects the bodyshell from stone chipping, wet and dirt. In keeping with all Mercedes passenger cars, the new SLK-Class is also protected by a 30-year MobiloLife warranty.
During wind-tunnel testing they focused their attentions on maintaining a draught-free interior, as this was crucial to creating an effective system of neck-level heating. The result is a seating position which is matched to the height of the windscreen frame so that the airflow is directed over the heads of the SLK passengers; this means they are truly screened from the wind when seated in the car, making the journey a much more comfortable one. The new SLK-Class also comes with a draught-stop as standard. The draught-stop is simply pulled over the two roll-over bars and secured by means of press studs. The fine-mesh structure results in a uniform distribution of air to avoid the high flow speeds which could otherwise be sensed as a draught. The same function is also fulfilled by the three-section, transparent draught-stop which is available as an accessory for the new SLK-Class. Thanks to these aerodynamic measures, the prerequisites for optimising thermal comfort whist driving with the roof down had been fulfilled. However, the SLK developers had no intention of stopping there: as well as smoothing the airflow with the draught-stop, they wanted to warm the air up too. And after a development and testing phase which lasted several years, their efforts were rewarded with the creation of the AIRSCARF system.
PTC heating element in seat backrests
Over the course of numerous test runs, the seat development team in Sindelfingen tried out a number of dif
ferent ideas and concepts for the neck-level heating system, and soon came to the conclusion that only a system that was integrated into either the seat or the head restraint could achieve the desired level of heating. In other words, the technology used had to be both small enough to fit into the SLK seats and at the same time powerful enough to generate enough thermal energy to heat the airflow in the roadster interior with the roof down.
The engineers at Mercedes were able to resolve these conflicting technical objectives using state-of-the-art, high-performance ceramic materials: various elements made of barium titanate and other metal oxides are energised, causing them to heat up in a matter of seconds and emit heat continuously. This does not drain the car’s 12-volt power supply though, as once a certain temperature is reached the electrical resis-tance of the ceramic material suddenly jumps, thereby reducing power consumption; heat output remains unchanged, however. This produces an equilibrium between the electrical energy the ceramic material is fed with and the heat output it produces.
The experts refer to this state as a "Positive Temperature Coefficient" or PTC for short. Meanwhile, the ceramic heating element is able to prevent itself from overheating by monitoring its surface temperature and automatically reducing the output if necessary.
As well as the compact design, this technology’s key benefits are its speed when heating up and the constant heat output.
The PTC air heater for the AIRSCARF system measures only a few centimetres in size, allowing it to fit into the backrest of the SLK seat. It consists of a number of rectan-gular ceramic elements with a total heat output of around 216 watts. The heat produced is dissipated into the air through aluminium fins which are positioned between the individual ceramic elements. A blower directs the air though a plastic duct until it reaches the head restraint where it flows out of a special vent to warm up the neck, throat and head of the seat occupant.
AIRSCARF regulated according to road speed and ambient temperature
AIRSCARF comes equipped with a three-speed switch and an electronic control module that adjusts heating at neck level to meet current requirements. A data bus keeps the micro-computer in contact with the speedometer, the temperature sensor in the centre console and the exterior thermometer of the Mercedes Roadster. The micro-computer then compares this up-to-the-minute data with the stored characteristic curves for particular ambient conditions and driving situations.
Pushing a button starts the system in switch position 3, after which it adjusts automatically depending on ambient temperature and road speed. The AIRSC ARF system adapts the blower speed constantly in order to achieve optimal distribution of the warm air in all situations. This adaptive control based on stored characteristic data is active up to a speed of 120 km/h. At higher speeds, the system operates at a constant setting. Anyone preferring to regulate the heating effect individually can also select three different output settings manually via the buttons in the centre console.
Sports seats: newly developed design with rigid magnesium frame
As well as the AIRSCARF, the seat experts at the Mercedes-Benz Technology Centre (MTC) worked on the development of further special technical features which are geared towards boosting ride comfort and increasing practicality. The sports seats boast a number of distinguishing features, including core springing and a layer of foam which provides a precise level of cushioning. Both of these elements – the core springs and the layer of foam – are incorporated into a robust cushion shell made from fibre-reinforced plastic. When it came to the seat backrests, the engineers opted for magnesium. By combining low weight with high strength, this high-tech material helps to boost occupant safety by providing extra lateral bracing for the side wall in the event of a side-on collision, for example. In addition to this, the silver-painted magnesium frame provides a solid basis for attaching the standard head/thorax sidebags. The backrests’ foam cushioning is applied directly onto cush-ion holders made from glass-fibre reinforced plastic. These are in turn supported by the magnesium frame.
The seats fitted in the SLK-Class feature fore-and-aft, height and squab-angle adjustment, allowing all occupants to find their ideal position. Compared to the predecessor model, the engineers at Mercedes have been able to increase the fore-and-aft adjustment range by nine millimetres to a total of 247 millimetres. The seat squab angle is adjusted automatically as the seat is moved forwards and backwards. The height adjustment range of the integral head restraints is 80 millimetres, whilst the slot in the seat backrest for the head restraint is concealed by a gaiter.
Yet another novel feature is the facility for folding the driver’s and passenger’s seat backrests forwards to improve access to the practical luggage net attached to the rear wall behind the seat. A coat hook can also be found on the rear of each seat backrest in the new SLK.
Mercedes-Benz is also able to supply electrically adjustable seats with a memory function as an option for the new SLK-Class: in this case, a microchip stores the individual setting data for the driver’s seat and relays the data to the electronic ignition key. Every time drivers insert their key in the ignition, the seat, steering wheel and exterior mirrors will automatically adjust to the stored positions.
The second electronic key included as standard with the SLK-Class is also compatible with this highly convenient memory function, while a third memory setting can be programmed using the button on the seat base without data transfer to an ignition key.
The memory facility includes an extra, automatic function which offers drivers even greater convenience: as soon as the door of the SLK-Class is opened or the electronic key is removed from the ignition, the driver’s seat slides back automatically and the steering column moves upwards to make getting into and out of the car easier.
Dimensional concept: extra room for driver and passenger alike
The revolutionary new AIRSCARF system, sports seats which are also ideally suited for longer journeys, the broad scope of adjustment for individual seat positioning and the seats’ increased fore-and-aft adjustment range all clearly demonstrate just how much progress has been made in the new SLK-Class when it comes to comfort and convenience compared to the previous model. The increase in the exterior body di-mensions plays a crucial role in this respect, as the car’s passengers also benefit from the additional length (+ 72 millimetres), width (+ 65 millimetres), height (+ 20 millimetres) and wheelbase length (+ 30 millimetres). The extra interior space means that passengers enjoy higher levels of comfort compared to the previous Roadster model.
The width at shoulder height, one of the key criteria for assessing interior comfort, now measures 1326 millimetres, representing an increase of 13 millimetres compared to before. The greater overall height of the body translates into 965 millimetres of headroom for the vehicle’s occupants, an extra 16 millimetres compared to the model it replaces.
Climate control: three systems available to choose from
Progress has also been made in terms of climate comfort in the new SLK-Class. There are now a total of three systems to choose from: the basic automatic heating system, THERMATIC and THERMOTRONIC.
Even the standard heating and ventilation system fitted by Mercedes-Benz, the automatic heating system, boasts an array of sophisticated microelectronics. The automatic heating system deploys sensors which permanently monitor the temperature inside the car and maintain the temperature constantly at the settings selected by the driver and passenger. The automatic heating system’s control panel in the centre console stands out by virtue of its attractive design, with all relevant functions clearly arranged using four ergonomically styled rotary switches: the temperature control for driver and passenger side, ten-speed blower control, air distribution, "Defrost" function, air recirculation and residual engine heat utilisation modes, plus the switch for the heated rear window.
As soon as the "Defrost" function is activated, the heating system automatically switches into heating mode, the heating output is increased to maximum and the electric motors inside the heating unit adjust the guide flaps in such a way that the airflow is accurately directed towards the windscreen and side windows.
As is the case with many of the heating functions, the automatic heating system’s standard air recirculation mode is also governed electronically. In order to prevent the windows from misting up, the duration of the recirculation mode is adjusted as a function of the ambient temperature, and is limited to a maximum of five minutes at temperatures below seven degrees Celsius. Once this period of time has elapsed, the air recirculation flap is opened by the system automatically, allowing fresh air to enter the interior of the car. The standard-fit interior filter remains active permanently, regardless of whether the automatic heating system is operating in fresh-air or air recirculation mode. As well as filtering out all particles of dust and diesel particulates larger than five micrometres in size, the filter also purifies the air by removing allergenic substances such as flower or grass pollen.
By conducting extensive airflow and climate-control simulations, the engineers at Mercedes have succeeded in optimising the air-intake and heating-duct cross sections. This has led to an audible difference, with the ventilation system now running far more quietly and even more effectively than before. The various ventilation outlets in the dashboard have also been increased in size and number with the intention of achieving a more pleasant ventilation of the interior which is free of draughts.
It was with this important consideration in mind that a system of indirect ventilation was developed. Featuring an air vent which is positioned beneath the perforated grille in the centre of the dashboard and is directed towards the windscreen, this method of indirect ventilation distributes cool air over a large area to prevent any draughts from forming on SLK models fitted with the THERMOTRONIC system. The majority of the other ventilation outlets in the dashboard are also fitted with individual adjustment wheels which can be used to reduce or even cut off the airflow from the outlet in question, or to direct it upwards, downwards or to the side.
Exterior: sporty genes
The front end plays an important part in the implementation of this concept. It symbolises sporty attributes such as power and performance by means of a long bonnet with a wide, slightly raised central axis, which tapers towards the striking front section and gives the sports roadster a new but familiar face. In this way the SLK-Class echoes a stylistic feature of the successful Mercedes-Benz Silver Arrows from Formula 1, unmistakably showing that it possesses the genes of the legendary Mercedes-Benz racing sports cars.
This muscular appearance is reinforced by two horizontal wing sections in the radiator grille, as well as an extended front apron with a large lower air intake, vertical vanes and spoiler edges swept well to the sides. The designers have used styling features like this to emphasise the width of the body and underline the powerful presence of the roadster.
Headlamps: striking to the last detail
The large headlamps likewise provide an unmistakable emphasis, both by day and by night: during daylight the highly polished surfaces reflect sunlight to make the lighting units sparkle like precious gems, and at night the state-of-the-art projection lamps characterise the lighting concept of the SLK-Class and show that the sophisticated design is backed up by equally sophisticated technology.
On looking closer one discovers a design refinement which shows the attention to detail by the Mercedes designers: the outer areas of the lenses continue the muscular contour jointly formed by the wing and bonnet, stylishly extending this to the front as a prominent curvature. The projection lenses of the headlamps follow precisely this shape, protruding forward below the curved glass and reminding one of high-quality camera lenses with their chrome surrounds.
In this way the headlamps both stand out and blend harmoniously into the lines of the front end: precision in both form and technology. This is particularly obvious in the version with bi-xenon headlamps. In this case the chrome surrounds of the projection lenses are partly transparent, which also provides interesting lighting effects when viewed from the side.
At the same time the striking interplay between the bonnet, radiator grille, headlamps and front apron confirms the technical quality of the SLK body. Everything appears to be cast from the same mould, both in form and colour. The front apron is perfectly integrated to form a stylistic unit with the bonnet, even though two different components are actually involved: the front apron encompasses the lower area of the front end with the Mercedes star, the radiator grille and the horizontal wing sections painted in the vehicle colour. The bonnet fits precisely around the upper section of the Mercedes star, lending a sense of completeness to the overall appearance.
The vario-roof was a multiple challenge for the designers. Firstly because the SLK is expected to look good whether the roof is open or closed, and secondly because, especially at the rear, the body design had to take into consideration a number of technical aspects which ensure faultless roof operation. In other words, the Vario-roof had to become an integral part of the design concept. The designers and engineers resolved this conflict of interests by teamwork, proving that even with the Vario-roof closed, a roadster can still be uncompromisingly a sports car.
Side view: muscular flanks
The new SLK-Class also shows its unmistakable character when viewed from the side: a long bonnet, wide doors and a short rear end – these are the typical features of a sports roadster, and they are even more prominent in this case. This is partly because the wheelbase is 30 mm longer and the body 72 mm wider than in the preceding model. These new dimensions emphasise the powerful proportions typical of a roadster. Owing to the extremely short front and rear overhangs, the gaze is focused on two very important features of a sports car, namely the wheels.
There is no doubt that it is the 16-inch wheels that underline the muscular and active character of the new SLK-Class when viewed from the side. Widely flared wings extend around the well-filled wheel arches like perfectly tones muscles, symbolising the athletic power of this roadster. The body language is clear: in these areas the metal skin is intentionally tailored to be rather tight and "body-conscious", with pronounced curves that arouse curiosity about the muscles concealed beneath it. This impression is even more striking in the six-cylinder SLK 350, as Mercedes-Benz uses 17-inch wheels as standard here.
As areas where sheer power and sporty dynamism are focused, the wheel arches form a dramatic contrast to the large, smooth flanks of the bodywork. Here the design exudes a sense of calm, and it is here that the Mercedes designers have placed their masterly signature by allowing lines and surfaces to interplay – thereby achieving stylish effects. The designers needed only one line to lend tautness to the entire side of the car. This rises slightly to the rear from the front wheel arch and creates a visual link with the rear end, characterising the wedge-shape of the body. In this way dynamism is given its own form without compromising the elegance characteristic of a Mercedes-Benz.
At the same time this line breaks the light and provides an interesting contour arising from the dramatic interplay between convex and concave surfaces.
Rear end: dominated by dynamism
The swept-back A-pillars accentuate the dynamic silhouette of the sports roadster. These continue the lines of the bonnet and transfer them to the rear end in a curve when the vario-roof is closed, the C-pillars dipping down gently into the boot lid and characterising its slightly embossed form. One might compare these flowing lines with a cord of muscle, too; it extends over both outer areas of the boot lid and gently transfers its strength down to the rear apron. This provides a visual separation from the spoiler lip, as it slightly raises the centre area of the boot lid, forms a horizontal line and contributes to the outstanding aerodynamics of the new SLK-Class.
The boot lid is not only special in styling terms, but also technically. To shape the centre area and emphasise the horizontal line of the spoiler lip, the SLK designers divided the outer skin of the boot lid into two and attached the lower section with the licence plate recess by laser welding. The laser works so precisely that the fine seam has the appearance of a design line which is continued sideways by the contour of the rear light cluster and gives the rear end of the SLK even greater formal consistency.
Other styling features at the rear of the SLK-Class include two oval exhaust tailpipes in chrome, striking rear lights with LED technology and an integral, powerfully accentuated rear apron. These too emphasise the uncompromising athleticism of this unique automobile. In other words, the new SLK-Class cuts an impressive figure from any angle and viewpoint.
Interior: man and machine combined
This also applies to the interior. The aim was to transfer the dynamic and emotive design language of the exterior to the interior, thereby emphasising the active character of the sports roadster. The result is a success: the interior design uncompromisingly follows the roadster philosophy and ensures a harmonious link between man and machine.
One finds out what this means in practice when getting into the new Mercedes sports car. The design of the instrument panel is sporty and technically oriented, with a clear priority on practicality but without appearing cool or featureless. The interesting colour contrast formed by the silver-coloured controls and the black surfaces on the steering wheel, centre console and transmission tunnel already conveys the distinctive design concept of the new SLK-Class. Here superior technology not only impresses by its reliable operation, but also by its sophisticated design.
It is particularly the cockpit that forms a focal point for a successful combination of form and function, technology and aesthetics: two large, clear dial instruments supply the driver with the most important information – vehicle speed, time, engine speed and fuel level. When designing the dials the stylists followed the example of high-quality chronometers – one glance at the white needles is sufficient to give the driver precise information. Despite being highly functional this concept is special in stylistic terms. This is ensured by the silver-painted tubes which surround each of the two dial instruments. Their elliptical faces are heavily slanted and inclined towards each other, providing the driver with an excellent view at all times. Concentrating on essential driving information was the major consideration during the design process. The divided display between the tubes is therefore intentionally a background feature. It creates a clear distinction between important, permanently visible information and additional information which is only accessed when needed.
"User Interface Design" is the name given by designers to this interesting discipline. It refers to the clear arrangement and design of displays, switches and controls in the instrument panel, so that the driver recognises their meaning at once though they blend perfectly into the overall design concept. A synthesis of ergonomics and aesthetics. The centre console of the new SLK-Class shows how well both aspects can harmonise. Every button, every rotary switch exudes precision and attention to detail.
The graphic user interfaces of the Audio 50 APS and COMAND APS displays were likewise a challenge for the designers. The screen graphics for the day and night displays, as well as the menu system, have been made so user-friendly that the driver is able to find his way around quickly and intuitively.
Dashboard: a bridge to the interior
However, the dashboard and centre console of the new sports roadster are not only good examples of the operating concept, they also have an important design function, namely to link the exterior with the interior. With its embossed centre surfaces and semi-oval upper ventilation grille, the dashboard continues the design theme of the bonnet and transfers it to the interior with a flourish. The centre console and tunnel cladding extend these flowing lines to the rear wall of the passenger compartment. In this way the body and interior combine as a work of art.
The SLK designers used the muscular, embossed surfaces of the dashboard to integrate two further striking features: the vertically arranged ventilation outlets that flank the centre console on both sides. In addition to fulfilling their task of supplying fresh air to the interior, these vents meet the design intention of combining technology with emotion. At the same time they lend more formal expression to the centre console and accentuate the cockpit feeling typical of a sports car.
This important effect was also a primary consideration when integrating the dashboard and door linings. When the doors are closed both components blend together perfectly in both form and colour. On entering the car one immediately feels comfortable and safe