For Audi, lightweight design is a philosophy that has implications for every area of a vehicle. As in motorsport, the engineers developing the S8 fought to save every gram of weight possible. Thanks to its compact design and thinner walls, the V10 weighs just 220 kilograms - 20 kilograms less than a well-known competitor's engine. Good axle load distribution and impressive road behaviour are the result. For the same reason, the battery and the power management are housed in the luggage compartment.



Chassis
Built for serene speed

The basic version of the Audi A8's air suspension, known as adaptive air suspension, already possesses distinctly sporty attributes thanks to its elaborate design. The axle links are made of aluminium. The front suspension consists of a four-link structure with two upper and two lower wishbones, and there is self-tracking trapezoidal-link suspension at the rear of the car.

Various details of the setup have been revised on Audi S8. The basis is adaptive air suspension - sport, the sports suspension that is available for Audi A8 as an option. On Audi S8, the characteristics of the air springs and the shock absorbers integrated into the air-spring bellows are somewhat firmer.

With a further reduction in rolling and pitching movements, the sporty top model behaves with even greater agility and manoeuvrability, but is as stable and safe as ever. The elastokinematics of the rubber mounts in the axles have likewise been modified in keeping with the character of the Audi S8. The rack-and-pinion power steering with its variable ratio is roughly ten percent more direct in the straight-ahead position, for even more spontaneous handling.

Drawing information from seven special sensors and a number of other parameters, the damping responds adaptively to the prevailing requirements in a fraction of a second.

Its control system features four driving modes - automatic, comfort, dynamic and lift - which the driver can call up via the terminal of the MMI operating system. The body's ride height is the same as with adaptive air suspension - sport, which is up to 20 mm lower depending on mode. On Audi S8, ground clearance is varied in three stages between 125 mm in the comfort mode and 95 mm at consistently high motorway speeds; this low level optimises the air flow and reduces fuel consumption as a result.

The Audi S8 is factory fitted with newly developed S-design cast aluminium wheels. Their dimension is 9 J x 20, the wide tyres are size 265/35. Tyres with run-flat characteristics based on the PAX system and 19-inch winter wheels are available as an option. An 18-inch brake system featuring four large-size ventilated discs assures a superlative braking performance. The brake callipers are painted black, and adorned with a titanium grey S8 badge at the front.

The optional ceramic brakes that were also recently made available for the twelve-cylinder Audi A8 are a special feature of the Audi S8. This makes Audi the only manufacturer worldwide to offer this technology in two production saloons. The impressive diameters of the ceramic brake discs - 380 mm at the front and 356 mm at the rear - are an immediate indication of their tremendous potential. The discs, which are 38 mm thick at the front and 28 mm at the rear, are made from a composite material comprising high-strength carbon fibres embedded in hard, frictionally resistant silicon carbide, a material that has already proved its worth in the field of aviation and space travel. The discs are bolted to a stainless steel chamber via resilient connecting elements.

The ceramic discs offer significant advantages compared with conventional steel discs. They offer a high braking performance, especially at the limit, and are largely unsusceptible to heat fading - a major safety bonus for a sporty high-performance car such as the Audi S8. The high-tech material is completely resistant to corrosion. Ceramic discs will last for up to 300,000 kilometres, four times as long as steel discs. And not only that, at around five kilograms per unit, they weigh half as much as their steel counterparts - this reduction in unsprung masses improves both handling and ride comfort.

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