Offical SLR pictures and tech notes

[The Jesal]

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Posted by: kak on Tuesday, August 19, 2003 - 03:34 PM CET

Back in the mid-1950s the three letters SLR acquired a hallowed status, as a Mercedes-Benz racing car of that name set new standards in the world of high-class Gran Turismo vehicles. Visually breathtaking and, thanks to innovative technology, superior to its rivals in terms of performance and handling, it spawned a legend. Mercedes-Benz and McLaren have successfully imbued the new Mercedes-Benz SLR McLaren (due to make its debut in autumn 2003) with the same charismatic qualities. Just like its legendary predecessor of 1955, this SLR incorporates new technological developments which are ahead of their time. For evidence, simply take a glance under the bonnet at the Mercedes-AMG V8 powerplant.

· High-torque V8 compressor engine with 460-kW/626-hp output
· 0 to 100 km/h in 3.8 seconds
· World's first series-produced car to have carbon fibre front crash structure
· High-performance brake discs made from fibre-reinforced ceramic

With its 5.5-litre displacement and screw-type compressor, the engine develops a peak output of 460 kW/626 hp and delivers its maximum torque of 780 Newtonmetres from 3250 rpm - a figure which remains constant across a broad engine speed range of up to 5000 rpm. With this kind of power under the bonnet, the Mercedes-Benz SLR McLaren delivers performance figures which are among the best in its class: this high-performance sports car takes just 3.8 seconds to sprint from 0 to 100 km/h, it passes the 200 km/h mark after 10.6 seconds, and from a standing start it takes just 28.8 seconds to reach 300 km/h. The two-seater has a top speed of 334 km/h (provisional figure).

In the interests of optimum weight distribution, optimum dynamic handling and high stability on braking, the Mercedes-Benz SLR McLaren has a front mid-engined design. The V8 powerplant is mounted on a robust aluminium frame and has a low installation position. Water-type charge-air cooling, three valves per cylinder, dry sump lubrication and four metal catalytic converters are further special features of this powerful engine - an engine which already meets stringent EU 4 exhaust gas regulations which are not due to come into force until 2005.

Three transmission programs for short, sporty gearshifts

The 5-speed automatic transmission, fitted as standard, is also designed for high performance. It allows the driver to choose between three programs, letting him or her determine the shift speed individually. When "Manual" is selected, the five gears can either be shifted using buttons on the steering wheel or using the selec-tor lever's Touchshift function. In manual mode the driver can select between three shift stages - "Sport", "SuperSport" and "Race" - significantly shortening the shift times still further for an even sportier drive.

High-tech material for exemplary safety and outstanding rigidity

The bodyshell of the high-performance sports car is also distinctly high-tech. Along with the front and rear structure and the passenger cell, the swing-wing doors and the bonnet, it is made entirely from carbon fibre composite. This light-weight yet extremely rigid material originated in the aeronautical and space industries and has also proven its benefits in today's Formula 1 race cars. The weight advantage of the high-tech material over steel is around 50 percent.

In addition to this, carbon fibres, on impact, are characterised by four to five times higher energy absorption than steel or aluminium. Mercedes-Benz exploits these qualities by inserting two 620-millimetre longitudinal members made from carbon fibre in the front structure of the new SLR. These absorb the entire energy of the crash in a head-on collision without exceeding tolerable deceleration values for the occupants. In an impact the fibres of these elements shred from front to rear with precisely calculated deformation behaviour, ensuring constant deceleration.

This makes the SLR the world's first series-produced car to have a front crash structure made entirely from carbon fibre. The carbon fibre longitudinal members each weigh just 3.4 kilograms.

The passenger cell of the high-performance sports car is also made entirely from this high-tech material. In a head-on, side-on or rear-end collision, it offers the passengers an extremely rigid, safe survival zone. At the rear, two internal longitudinal members made from laminated carbon fibre and a robust cross member take on the task of energy absorption in the event of a crash - as a rule the passenger cell remains structurally unaffected.

Adaptive front airbags which deploy in two stages depending on the severity of the accident, newly developed sidebags which protect the head, plus belt ten-sioners and belt force limiters all form part of the new SLR's occupant protection system.

Ceramic brake discs and SBC™ for exemplary braking safety

The brake discs of the cutting-edge swing-wing door vehicle are also made from a high-tech material which meets the highest of standards. Here Mercedes-Benz has used carbon fibre-reinforced ceramic to achieve outstanding performance, temperature-resistance and longevity. Thanks to the highly robust material, the SLR's large brake discs allow maximum deceleration of up to 1.3 g - a top value in a series-produced car. At the front axle alone a total brake pad area of 440 cm2 is available.

Further features of the new SLR include Sensotronic Brake Control (the electro-hydraulic braking system), the Electronic Stability Program (ESP ®), automatic tyre pressure monitoring, 18-inch wheels and aluminium suspension which bears the signature of experienced race car constructors - all of which create the necessary criteria for perfect dynamic handling and excellent driving safety.

Engine and transmission: V8 powerplant with motor racing in its genes

· High-tech powerplant with 780-Newtonmetre torque
· Metal catalytic converters for low exhaust gas emissions in line with EU 4 standard
· Sidepipes reminiscent of 1950s SLR models
· 5-speed automatic transmission with 3-stage manual shift program

An abundance of power and high-tech features from the world of motorsport - these are the defining characteristics of the V8 engine in the Mercedes-Benz SLR McLaren. Which means that the first 8-cylinder to be completely developed by Mercedes-AMG fits perfectly into the high-performance concept of the new Gran Turismo. When developing the powerplant, the AMG engineers applied both the expertise they had acquired during their three-decade involvement in motorsport and the stringent standards of the Mercedes-Benz brand. After an extensive concept phase, they decided in favour of an 8-cylinder design with a 5.5-litre displacement, a cylinder angle of 90 degrees, a screw-type compressor and a crankshaft supported by five bearings.

The result is impressive: from a mere 1500 rpm, the SLR powerplant delivers torque of over 600 Newtonmetres, rising to 700 Newtonmetres at 2000 rpm. The maximum of 780 Newtonmetres is available from 3250 rpm and remains constant in a broad engine speed range up to 5000 rpm. The supreme torque curve, coupled with the agile response of a sporty engine which never denies its high-performance character (it offers a peak output of 460 kW/626 hp at 6500 rpm - an extraordinarily high engine speed for this displacement size) speak a powerful language. As the figures indicate, the new SLR is endowed with what is currently one of the most powerful engines to be found in a series-produced roadgoing sports car. An overview of the key data:

Cylinder arrangement V8
Cylinder angle 90o
Valves per cylinder 3
Displacement 5439 cc
Bore/stroke 97.0/92.0 mm
Cylinder spacing 106 mm
Compression ratio 8.8 : 1
Output 460 kW/ 626 hp at 6500 rpm
Max. torque 780 Nm at 3250-5000 rpm
Engine weight 232 kg
Power/weight ratio 1.9 kW/kg

With this much power under the bonnet, the Mercedes-Benz SLR McLaren's performance figures are among the best in its class:

0-100 km/h 3.8 s*
0-200 km/h 10.6 s*
0-300 km/h 28.8 s*
Top speed 334 km/h*

*provisional figures

Fuel consumption is 14.8 litres per 100 kilometres (NEDC combined consump-tion, provisional figure).

Power from screw-type compressor

To ensure good cylinder charging, the engine has a mechanical compressor with two screw-type aluminium rotors which, in the interests of low friction losses, are Teflon-coated. The charger is so compact that the engine specialists were able to install it between the two cylinder banks of the V8 powerplant. Despite the space-saving design, its innovative technology allows a significantly higher charge pressure than conventional mechanical chargers because the two rotors achieve a top speed of around 23,000 revs per minute, forcing air into the air inlet of the 5.5-litre powerplant at a maximum pressure of 0.9 bar. This means that they compress around 1850 kilograms of air into the eight combustion chambers per hour - which is up to 30 percent more than the figure achieved by rival charging systems.

In order to ensure the greatest possible efficiency, the AMG engineers created an intelligent engine management system which regulates the operation of the screw-type compressor according to the engine speed and load. This means that the charger is only active when it is needed. Nevertheless, the system ensures that the maximum output is available as soon as the driver calls it up by stepping on the accelerator. When this occurs, the electronics of the engine management system trigger an electromagnetic coupling which immediately activates the compressor, which is powered by a separate poly-V-belt. Because the charger de-livers its output in fractions of a second, even the most perceptive driver will not notice the phases without charger support. The charger system's air recirculation flap, opened under partial load, helps reduce fuel consumption.

Two charge-air coolers with separate water circuit

In addition to the compressor, the electronics also monitor all other variables relevant to the engine - both the powertrain management for the pedal-dependent drive characteristics and the implementation of spontaneous transmission or ESP® interventions. They also ensure optimum control of the water circuit for the charge-air cooling system, as efficient charge-air cooling is essential where high output is concerned. This is because cold air is denser than warm and also con-tains significantly more oxygen for combustion. In the Mercedes-Benz SLR McLaren's V8 engine, two separate charge-air coolers are responsible for this key task - one per cylinder. This ensures that loss of pressure is very low.

The highly effective engine-based charge-air coolers operate along the lines of an air/water heat exchanger: the air, compressed and hence warmed by the compressor, is cooled via a separate water circuit - making the process independent of the temperature outside. This means that the 8-cylinder can deliver its maxi-mum output and torque spontaneously at any time. The high performance figures of the 8-cylinder engine in the new SLR, however, not only demand good cooling of the combustion air but also result in an overall increase in engine cooling requirements. The engineers met this need by incorporating generous cooling air inlets and outlets and a powerful 850-Watt suction-type fan.

Crankcase with dry sump lubrication

The Mercedes-AMG GmbH engineers also applied their extensive experience in the world of motorsport and in the design of high-performance engines to other details of the SLR powerplant. The entire engine housing, for example, and the lower section of the closed crankcase are cast in aluminium. Each crankshaft is finely balanced and is supported by five bearings made from durable plastic, allowing long-term transfer of the impressive forces from the compressor engine.

The pistons are forged and are therefore only manufactured in minimal numbers. Like the forged lightweight conrods, they are precisely measured and weighed and allocated to the individual engines in such a way as to produce minimal balancing tolerances. The pistons move in highly robust, wear-resistant and friction-optimised walls made from a special compound which is otherwise only used in motor racing. Dual oil injection effectively cools the pistons.

The design of the powerplant's oil cooling system is also based on experience gathered in the world of motor racing: a sophisticated dry sump lubrication system with an oil capacity of around eleven litres, combined with a five-stage oil suction pump and a two-stage oil pressure pump, ensures reliable lubrication under all on-road conditions. An important side effect of this technology is that, because of the dry sump lubrication, usually only used in motor racing vehicles, the engine is less tall and can therefore be installed at a lower level, allowing a low centre of gravity which benefits dynamic handling.

Following the usual practice at Mercedes-AMG, each SLR engine is manufactured by hand. In order to achieve the highest quality, the principle of 'one man, one engine' is applied. This means that each powerplant is the responsibility of one AMG engineer, who carries out the entire engine assembly process - from installing the crankshaft in the engine block and assembling the camshafts and the compressor to cabling.

Powerful high-pressure pumps in the tanks

The SLR's high-performance engine draws its fuel from two interconnected aluminium tanks. They are installed at a relatively low level to the left and right of the rear axle in order to keep the centre of gravity as low as possible to further en-hance dynamic handling. The tanks, which have an overall capacity of 97.6 litres - of which twelve litres form the reserve - are equipped with two integral high-pressure fuel pumps. These are controlled by the engine management system and ensure that the fuel supply matches the engine speed and load. Here too a highly effective, SLR-specific solution was developed: one pump operates constantly while the second is only activated as required.

Four metal catalytic converters for efficient emission control

Where the engine is concerned, secondary air injection and dual ignition create the criteria required for low exhaust gas emissions. A sophisticated exhaust gas system complements these measures: the cascade-design twin-pipe system consists on both sides of a bulkhead-mounted catalytic converter and a main catalytic converter with a special noble metal coating, accommodated in the same housing. The state-of-the-art metal design allows extremely thin wall thicknesses and therefore a very low exhaust gas backpressure. Thanks to its cutting-edge technology of its engine management and emission control systems, the new SLR's 8-cylinder engine already meets the stringent exhaust gas limits stipulated by EU 4 plus the current US limits.

On each side of the vehicle the catalytic converter housing opens into a rear silencer which, just behind the front wheels, flows into two stainless steel pipes with a diameter of 60 millimetres. These sidepipes - a further reminder of the 1950s SLR racers - allow the smooth-surfaced underbody, which plays a crucial role in producing the new Mercedes-Benz SLR McLaren's first-class aerodynamic properties. The silencers are folded several times in precisely calculated acoustic sections which produce the thrilling characteristic engine sound of the Mercedes-Benz SLR McLaren. The capacity of each silencer is 19.6 litres.

Manual transmission program for racing car-style shift times

The five-speed automatic transmission, developed by Mercedes-Benz and already successfully used in several exceptionally powerful models, is also designed for high performance. It has been specially optimised for very high torque and also offers the driver the option of choosing between different shift characteristics. The transmission transmits the engine power via a finely balanced aluminium and steel powertrain to the differential and the rear axle.

The Speedshift system, developed by Mercedes-AMG for particularly sporty driving, offers even more functions in the new SLR. The driver can decide, for example, whether to leave the shift work to the automatic transmission or to shift gears manually. He or she can also select the shift speed, determining how sporty the gearshifts are. A rotary switch in the centre console offers a choice of three settings: "Manual", "Comfort" and "Sport". The activated programme is indicated in the instrument cluster display by the letters "M", "C" or "S".

"Comfort" and "Sport" are automatic shift programs which, as the names indicate, place the emphasis either on comfort or on a more sporty drive. In "Manual" mode, on the other hand, the driver can select the five gears either using the but-tons on the steering wheel or using the Touchshift function on the selector lever. When "Manual" is selected, he or she also has the option of choosing between three shift stages for a sportier driving style:

· Stage I = "Sport"
· Stage II = "SuperSport"
· Stage III = "Race"

In the sequence indicated here, the response, reaction and closing times of the couplings in the automatic transmission, and hence the shift processes themselves, become increasingly shorter.

Bodyshell and safety: high-tech materials for exemplary occupant protection

· Carbon fibre body, ceramic brake discs
· Rigidity and crash safety of the highest level
· Result of several years of successful materials research
· Adaptive front airbags and newly developed sidebags

When it comes to body and safety technology the new Mercedes-Benz SLR McLaren yet again lives up to its reputation as an innovative force among today's Gran Turismos. High-tech materials from the field of aeronautical technology make their debut in a series-produced car here: carbon fibre is used for manufacturing the body, lending it its low weight and an exemplary rigidity and strength previously only achieved in Formula 1 race cars. The crash safety standards achieved using this innovative material are equally high.
Carbon fibre has been used to great effect in the aeronautical industry for some time. The rudder unit, vertical rudder, landing flaps and other parts of most airbuses are made from this material, in the development and series use of which the scientists at DaimlerChrysler Research played a significant role. Their expertise and the extensive experience of the Mercedes-Benz and McLaren experts in the field of race car design can now, for the first time, be seen in a series-produced car: the entire bodyshell and the doors and bonnet of the SLR are made from cor-rosion-resistant carbon fibre composite.

While offering the same strength as their steel or aluminium counterparts, carbon fibre components weigh up to 50 percent less than comparable steel components and up to 30 percent less than aluminium components. This makes carbon fibre composite the material of choice for manufacturing high-performance cars, because lower weight not only means lower fuel consumption but also outstanding transfer of power to the road. The lower the mass to be accelerated and braked, the better the agility. In fact, thanks to the extensive use of carbon fibre composites, the primary structure of the Mercedes-Benz SLR McLaren is around 30 percent lighter than the conventional steel construction of a comparable front mid-engined vehicle.

Carbon fibre composite offers significantly higher energy absorption

On top of this, the state-of-the-art lightweight material is also characterised by very good energy absorption. The figures here for carbon fibre composites are around four to five times higher than those for metal materials. Formula 1 constructors have been exploiting this quality for several years, manufacturing the crash structure of their race cars from carbon fibre composite. The result has been a significant fall in the number of serious injuries incurred in high-speed accidents in this top motorsportdiscipline.

The monocoque - or, to put it another way, the passenger cell - of the new Mercedes-Benz SLR McLaren is also made entirely from this high-tech material. In the event of a head-on, side-on or rearend collision, it offers the passengers a highly rigid and hence safe survival zone.

Carbon fibre crash elements in the front structure

The innovative fibre composite demonstrates its safety advantages particularly impressively in the front structure of the SLR bodyshell. Here two conical carbon fibre composite elements, each approximately 620 millimetres in length and weighing just 3.4 kilograms, are enough to absorb the full energy of the crash in a defined frontal collision without exceeding tolerable deceleration values for the passengers. The carbon fibre composite members are bolted onto the aluminium structure of the engine mounts; at the front they are connected to the remaining bodyshell structure by means of a cross member and a horizontal sandwich panel made from carbon fibre composite. This makes the SLR the world's first series-produced car to have a front crash structure manufactured entirely from carbon fibre.

In a collision, the fibres of the carbon fibre composite elements shred from front to rear, absorbing the energy of the impact with constant deceleration. Thanks to this steady deformation behaviour, the energy absorption of the carbon fibre longitudinal members can be tuned to meet specific requirements. The engineers achieve this, for example, by creating a constantly changing cross-sectional area for the components. This fine tuning means that the deceleration values result not only in predictable energy absorption behaviour but also in a weight advantage, because this design uses only as much material as is actually needed.

Four-year development of carbon fibre composite longitudinal members

The two conical longitudinal members of the front crash structure are made up of a main body and an internal web - a basic configuration which proved to be the most successful during the four-year development of this SLR component. The aim of the engineers from the Advanced Design department at the Mercedes-Benz Technology Centre in Sindelfingen and of DaimlerChrysler Research was not only to develop longitudinal members which offered an unprecedented degree of passive safety, high rigidity, tremendous strength and as low a weight as possible, but also to draw up manufacturing concepts which involved a high degree of automation to enable series production. In doing so, the experts entered uncharted technological territory.

In the early development phase they had succeeded for the first time in using a specially developed algorithm to carry out dynamic crash calculations for carbon fibre composites. The sophisticated computer simulations were crucial when it came to optimising the design of the longitudinal members for the front crash structure.

In a parallel operation, materials experts tested the calculated findings in practice using models which they exposed to precisely defined stresses in drop tests. As a result of this process, the exemplary deceleration and deformation behaviour of the carbon fibre composite longitudinal members in the front structure of the new Mercedes-Benz SLR McLaren was gradually defined.

The first automated production of carbon fibre composite components

To date, carbon fibre composite components for racing cars and for the aeronautical and space industries have been manufactured by hand - a time-consuming process. The challenge for the Mercedes engineers was to use their experience in this field to develop automated methods of series production. To do this they divided the manufacturing process into separate stages, manufacturing of the preform being followed by impregnation with resin and hardening.

In order to allow extensive automation of the preform manufacturing process (the preform also being made from carbon fibre), the materials experts at Mercedes-Benz cast a glance at the work of their colleagues in the textile industry and adapted traditional manufacturing methods used in this sector, such as sewing, knitting, weaving and braiding, for the processing of high-performance carbon fibres.

To take an example, the web of the SLR's longitudinal members is formed from several layers of carbon fibre placed on top of one another and sewed together by machine. Once the piece has been cut to shape and the ends folded up to form a double T profile, the web blank is inserted in a polystyrene braiding core. This core element is clamped into a specially developed braiding machine, which braids together the longitudinal members from 25,000 extremely fine, individual carbon filaments, these being unwound simultaneously from 48 reels. This technology allows the fibre material to be braided around the core at a precisely cal-culated angle to create the required contour. Several layers are even laid on top of one another in certain areas, depending on the required thickness. An innovative method was developed for this process too.

In a further manufacturing process, a computer-controlled tufting machine joins the inner web to the braid of the longitudinal member. The braid core is removed and the preform of the longitudinal member is cut to the correct size. The preform is then injected with resin. Several, now patented, solutions had to be developed and tested in order to ensure short cycle times and high repeat precision for this manufacturing process - crucial qualities in series production. The manufacture of the complex fibre struc-ture of the longitudinal members using a braiding machine requires a cycle time of just twelve minutes, which illustrates the unit potential that this innovative manufacturing technology offers.

New method for manufacturing rear shelf

The rear shelf of the new SLR provides a further example of the new production techniques used by Mercedes-Benz for carbon fibre processing. It has a very complex form with several apertures, yet it is automatically manufactured as a single part. To achieve this, Mercedes-Benz and its collaborative partners adapted the SMC method (SMC - Sheet Moulding Compound) to create "Advanced SMC". Its advantage is that the carbon fibre mats are no longer manufactured by hand but by machine.

Here a handling system positions individual carbon fibre composite layers at precalculated angles and in preset positions which correspond to the principal form of the component, thereby creating the blank. Under heat this blank is then pressed, and in the process it takes on the precisely calculated form of the rear shelf. No subsequent reworking is required.

In the new SLR, Mercedes-Benz is the first car manufacturer to use components which are manufactured using the "Advanced SMC" method.

The British company McLaren Composites also manufactures over 50 carbon fibre and fibreglass components for the high-performance sports car. Here too familiar processes from the aeronautical industry were adapted and developed. The degree of integration achieved in the manufacture of the bodyshell is remarkable. The entire floor assembly, for example, including all support members and securing elements, are made in one piece. The cavities of the carbon fibre composite roof frame structure (also manufactured as a single piece) are automatically filled with foam before the resin injection, creating a particularly crashproof sandwich structure. High-strength bonding and riveting techniques ensure a reliable connection between the individual carbon components of the chassis and the body-shell. The aluminium engine mounts are bolted to the carbon fibre composite bulkhead and also bonded in place. The carbon structure includes integral metal link points for the aluminium and steel rear axle.

Retention system with adaptive airbags, sidebags and kneebags

A cutting-edge retention system with six airbags, belt tensioners and belt force limiters completes the SLR's sophisticated safety concept, ensuring that it meets all Mercedes standards.

In the event of a head-on collision of a specific severity, the electronic control unit first triggers the high-performance belt tensions, which pull up to 15 centimetres of loose belt taut in fractions of a second, reducing the forward displacement of the occupants as a result of the impact. The Mercedes-Benz SLR McLaren is also fitted with kneebags, which - together with the two-stage driver and front-passenger airbags - provide a large protective cushion for the driver and front passenger, supporting the effect of the seat belts and belt tensioners.

Upfront sensors for rapid airbag deployment

The belt tensioners are also activated if a roll-over situation is detected. A roll-over sensor reliably recognises this type of accident and supplies its data at lightning speed to the central control unit for the retention systems. The sensor is located on the centre tunnel.

Sophisticated sensors also allow adaptive control of the front airbags, which de-ploy according to the severity of the accident. If the sensors register a light head-on collision, they each trigger just one chamber of the two-stage gas generators, and the 64-litre driver airbag and 125-litre front passenger airbag are deployed with lower internal pressure. If the sensors register a higher severity of accident, the electronics also trigger the second chamber of the gas generators and the airbags fill with higher pressure.Two upfront sensors on the radiator cross member also assist this adaptive deployment of the retention systems. Thanks to their exposed installation position in the front structure, they detect the severity of the impact even earlier and more precisely. The deployment algorithm uses both this signal and the signal from the central crash sensor on the centre tunnel.

While the occupants sink safely into the airbags, the belt force limiters reduce the force of the belt on the upper body, decreasing even further the risk of light chest and shoulder injuries.

Sidebags provide extra protection for the head

Protection in the event of a side impact is optimised by integral sidebags in the doors. These cushion both the head and the upper torso and are sometimes, therefore, referred to as "head/thorax bags". In a side-on collision, this specially developed side airbag rips open a seam above the armrest and inflates in milliseconds to form an asymmetrical airbag, the upper edge of which, when inflated, extends higher than that of the familiar sidebag. This design means that the air cushion reduces the risk of the head hitting the side windows or any object which may penetrate the interior. It also holds back glass shards and other objects which could enter the interior in a collision.

The automatic child seat recognition system, developed by Mercedes-Benz, is also part of the SLR's standard equipment. It deactivates the front passenger airbag if a special child seat from the Mercedes-Benz accessories range is installed on the front passenger seat. These child seats have a transponder system which receives and responds to signals from two antennae in the seat upholstery. As a result of the exchange of data, the airbag electronics recognise that a child seat is fitted and deactivate the airbag on the front passenger side since its deployment is not desirable in these circumstances. The belt tensioner and sidebag remain activated, offering the young passenger additional protection in the event of an accident.

Swing-wing doors with large angle of opening

If there is one distinctive feature that the new Gran Turismo has adopted from the Uhlenhaut Coupé, the 1955 coupé version of the legendary SLR race car, it is the doors. In their modern interpretation, however, they are attached to the front roof pillars rather than to the roof itself and swing forwards and upwards at a 107-degree angle. This new concept ensures greater safety, an exciting look and, because of the large opening angle, allows comfortable access to the interior for the driver and front passenger.

The high-performance sports car's luggage capacity is equally striking. The leather and velour-trimmed boot holds a total of 272 litres (using the VDA measuring method). Flaps below it provide easy access to stowage compartments for the washer and brake fluid reservoirs, the two batteries and tools. The designers opted for this unusual arrangement in order to achieve sports car-style weight distribution with a low centre of gravity close to the centre of the vehicle.

Suspension: top performance for the race track and the motorway

· Aluminium double wishbone suspension with 18-inch wheels
· Highly-performance brake discs made from carbon fibre-reinforced ceramic
· Electrohydraulic brake system (SBC™) plus ESP®
· Automatically adaptable airbrake in boot lid

Highly developed motor racing technology, high-performance control systems and cutting-edge materials - a unique combination which propels the Mercedes-Benz SLR McLaren into a new dimension in sports car dynamics, helping it to achieve top figures in three key areas: agility, active safety and comfort. In the process, the SLR suspension meets every criteria a discerning car driver would expect to find in a Gran Turismo with a Mercedes star.
The axle design bears the signature of experienced racing car developers, with double wishbone suspension at the front and rear. The lower struts are arranged so that, as the springs compress and when cornering at speed, the wheels have a negative camber. This ensures the best possible contact with the road in every situation. At the same time the axle technology prevents the front of the car from diving when braking heavily and the rear from diving when accelerating.

Aluminium was the key material for the developers of the new Mercedes-Benz SLR McLaren's suspension. The wishbones are made from forged aluminium, while the wheel mounts are cast in aluminium. In addition to a whole series of other advantages over conventional steel designs, the lightweight nature of the material allows the suspension to react significantly faster and to respond more sensitively.

The relatively long wheelbase (at 2700 millimetres) also contributes to the SLR's exemplary handling and makes itself noticed above all in the car's exemplary directional stability, while the large track width, combined with the low centre of gravity, allows high cornering speeds.

Springing/damping combinations at the front and rear axle and an anti-roll bar at the front complete the suspension structure. The anti-roll bar is positioned above the front axle and - as in Formula 1 - is controlled via rocker arms. This means that it does not take up any installation space which could impair the smooth line of the underbody - a vital factor when it comes to the sports car's outstanding aerodynamic properties.

The speed-sensitive rack-and-pinion power steering also corresponds with the in-telligent lightweight concept. In comparison with other steering systems, this design is characterised by a significantly lower weight. Thanks to its low installation position in front of the engine and the gear ratio of 12.6, the steering system re-sponds directly to the driver's commands and carries them out with high precision. The three-spoke steering wheel has a diameter of 380 millimetres and is fitted with an electric motor which allows it to be positioned to suit the individual driver. It can be adjusted by 60 millimetres for reach, and the height of the steering wheel can be varied by 2.7 degrees.

SBC™ and ESP® for sporty dynamic handling with high level of active safety

The electrohydraulic braking system, Sensotronic Brake Control, a milestone in car technology, forms part of the standard equipment of the Mercedes-Benz SLR McLaren. It processes data from various sensors regarding the current status of the vehicle and can use this to calculate and apportion the optimum brake pressure for each wheel at lightning speed. A high-pressure accumulator holds the brake fluid, which flows into the system at a pressure of 140 to 160 bar. This also optimises the function of the Electronic Stability Program (ESP®), which keeps the SLR safely on track by applying targeted brake impulses to the individual wheels and/or reducing the engine torque. Here too SBC™ offers the advantage of higher dynamism and precision: thanks to even faster and even more finely metered brake impulses from the SBC™ high-pressure accumulator, ESP® can stabilise a swerving vehicle comfortably at an early stage.

The coordination of this system with the Electronic Stability Program (ESP®) was a particular challenge for the engineers of the high-performance sports car. Their aim was to adapt the dynamic handling control system to the vehicle's distinctly sporty performance yet maintain the usual safety standards, achieving an ideal compromise between outstanding dynamic handling and exemplary directional stability. Here too SBC™ demonstrated its strengths, being able to deliver adequate braking power at lightning speed in every on-road situation, thanks to its sophisticated sensors and the high-pressure accumulator, making a key contribution to the precision handling of the SLR. It was therefore possible to allow a very sporty driving style with controlled side-slip angles in keeping with the character of the high-performance car without compromising active safety. On top of this, SBC™ significantly enhances active safety in critical situations:

· Emergency braking: SBC™ recognises the driver's sudden switch from the accelerator to the brake as an indication of an emergency situation and is able to react automatically. With the aid of the high-pressure accumulator, the system increases the pressure in the brake lines and positions the brake pads against the brake discs so that they can grip with full force the moment the driver steps on the brake.

· In the wet: through brief, regular application of the brakes, Sensotronic Brake Control ensures that the film of water on the brake discs is stripped away so that the brakes can always operate to full effect. This automatic drying function is activated whenever the windscreen wipers have been operat-ing for a certain length of time. The finely metered brake impulses are not no-ticeable to the driver.

· Braking on bends: thanks to variable brake force distribution, SBC™ is able to exert an active influence over the sports car's self-steering behaviour. While conventional braking systems always apply the braking pressure to the wheels on the inside and the wheels on the outside of the bend in the same ratio, SBC™ can distribute the brake forces to suit the situation. The system automatically increases the brake force at the wheels on the outside of the bend because, thanks to the higher wheel contact forces, they are able to transmit greater braking forces. At the same time the braking forces at the wheels on the inside of the bend are reduced to benefit lateral traction, which is so important to directional stability. The result is more stable braking behaviour and excellent deceleration figures.

Sensotronic Brake Control also offers special additional functions for even greater safety and comfort:

· The Soft-Stop function allows the vehicle to come to a particularly gentle stop, which will be much appreciated in city traffic, involving frequent stops at traffic lights. It is made possible by finely metered pressure control. The Soft-Stop function is permanently activated; only on emergency braking and when manoeuvring does the system ensure that priority is given to rapid deceleration.

· Start-Off Assist (SBC™ Hold) prevents the car from unintentionally creeping forwards or rolling backwards on hills and steep gradients. A brief but firm ap-plication of the brake pedal is all it takes to activate this function.

· Tailback Assist (SBC™ Stop) can be activated using the cruise control lever when the vehicle is at a standstill or travelling at a maximum of 15 km/h. The advantage of this is that in stop/go traffic the driver only needs to use the accelerator; when the driver takes his or her foot off the accelerator, SBC™ brakes the SLR to a standstill with constant deceleration. Tailback Assist can remain active up to a speed of 60 km/h. It is automatically deactivated at higher speeds. When Tailback Assist is activated, the letters "SBC S" appear in the instrument cluster.

Ceramic brake discs for top performance

Mercedes-Benz has optimised the outstanding properties of the Sensotronic Brake Control system in the new SLR with a braking system which also marks a technological high-point in a high-performance car: at the front and rear axle of the cutting-edge swing-wing door vehicle, brake discs made from fibre-reinforced ceramic ensure reliable deceleration. Their development is based on the one hand on the results of DaimlerChrysler materials research and on the other on Mercedes-AMG's experience of high-tech brakes in touring cars and GT sport. Here Mercedes-Benz yet again underlines its leading role in the development of groundbreaking technologies for car production.

In manufacturing the brake discs, the carbon fibre, powdered carbon and resin are pressed into shape at high pressure and baked with a silicon infiltration at temperatures of around 1500 Celsius to form the ceramic. The advantages of this composite material are considerable: in addition to being characterised by an extremely sensitive response, the Mercedes-Benz SLR McLaren's brake discs demonstrate a high temperature-resistance of up to 1000 Celsius, which produces a fade-resistance when braking at high speed never before achieved in a series-produced car. The result is brake power of up to 2000 hp.

Further advantages of the new brake material include...

· ... the long life of the brake discs - up to 300,000 kilometres.
· ... the low maintenance requirements of the corrosion-free brake discs.
· ... the lower weight - up to 60 percent less than conventional brake discs - a further bonus in terms of dynamic handling and ride comfort.
· ... even more comfortable braking - the low thermal expansion of the ceramic discs means reduced heat friction under high stress. Cold friction, familiar from cast iron brake discs, is also significantly reduced with ceramic brakes.

Brake pad area of 440 cm2 at the front axle

The design of the callipers was specially adapted to the fibre-reinforced ceramic brake discs. Mercedes-Benz developed eight-piston fixed callipers especially for this fast Gran Turismo, allowing excellent deceleration at the front axle. Special channels, which actively feed the cooling air to the outside of the brake callipers, ensure optimum cooling of the brakes.

Overall in the Mercedes-Benz SLR McLaren there is a total brake pad area of 440 square centimetres at the front axle alone - a top value which, in combination with the extremely robust high-tech material of the brake discs, allows maximum deceleration of up to 1.3 g. This results in outstanding stopping distances: on emergency braking from 100 km/h the Mercedes-Benz SLR McLaren comes to a standstill after an average of 34.9 metres.

Adaptable rear spoiler as airbrake

The outstanding performance of the SLR is also aided by the adaptable spoiler - known as the airbrake - in the boot lid. If the driver steps heavily on the brake pedal, the rear spoiler rises to an angle of 65 degrees, boosting the braking effect by producing greater aerodynamic drag. When braking from high speeds, it lends the SLR outstanding stability.

In most situations the electronics control the airbrake as required. However, the driver can also opt to take control of the adjustments using the switch in the centre console, manually raising the rear spoiler up to an angle of 30 degrees.

18-inch wheels as standard

Attractive 18-inch light-alloy wheels are part of the standard equipment of the Mercedes-Benz SLR McLaren. The sporty, 10-spoke wheels are fitted with different widths of tyres at the front and rear. 5-spoke wheels are available as an option at no extra cost. 19-inch turbine-design wheels, which particularly emphasise the dynamic character of the Gran Turismo, are available as an optional extra.

An electronic system monitors the air pressure in the tyres of the Mercedes-Benz SLR McLaren. Its sensors are situated in the tyre valves and measure both air pressure and air temperature inside the tyre. Since it is not possible to install cable connections to the wheels, the information is transmitted by radio. Each sensor sends its data readings around once per minute to special antennae in the wheel arches which pass the information on to a control unit. This unit uses individual identifiers to distinguish between the signals from the four wheels and is able to inform the driver of the air pressure in each tyre via the central display in the cockpit.

[The Jesal]

A 5 speed auto?

[SPEE]

the pix didn't show.. but i'm sure they are pimpster

[Tuna]

They have 6 speed autos out now

[Timmahhh]

Dammit Mercedes, make a manual trans already!

[Tuna]

I don't know if I like this Benz ... i liked he old school Gull-wing , and I loved the CLK GTR, this one just doenst do it for me, Kind of reminds me of the old school Jaguar coupes.