High-performance brakes with dual-rate servo
The braking system is also matched to the powerful potential of the Audi S4. The ventilated discs measure 340 millimetres in diameter at the front, 300 mm at the rear. The system is operated via a new dual-rate servo. This gives the driver a sporty, firm feel at the brake pedal when low to medium rates of retardation are needed, but retains excellent controllability.
In the comfort braking range of up to around 0.5 g deceleration, the brake servo's ratio is on a par with the other A4 models with a factor of 5.5 and thus ensures especially good control. Above 0.5 g the ratio is raised to the factor 12. This means that deceleration increases at a disproportionately high rate compared with brake actuating force - a clear advantage for a sporting style of driving.
The S4 thus achieves full deceleration with comparably low pedal force and with less pedal travel than on a conventional system. The Electronic Stabilisation Program ESP 5.7 including hydraulic brake assist ensures active driving safety.
The top sports model in the A4 series: this claim is satisfied even by the standard equipment specification that the S4 and S4 Avant offer.
This of course includes safety features such as full-size front airbags, side airbags integrated into the seat backs and the head airbag system known as sideguard which covers the entire side window area and the A-posts.
Active safety benefits from the Electronic Stabilisation Program ESP and the high-performance brake system with dual-rate servo and brake assist. Standard features also include quattro permanent four-wheel drive which converts engine power with unfailing efficiency into forward movement and also ensures extremely safe handling in all road and weather conditions.
The S4 sports suspension lowers the vehicle's ride height by 20 millimetres and - apart from its sporty appearance - means a clear advantage in terms of dynamic handling.
The exterior of the S4 models differs from the other models in the A4 series through Avus-design cast aluminium wheels of size 8x18-inch. Other identifying features include electrically adjustable and heated aluminium-design door mirrors, a discreet rear spoiler on the saloon, an original radiator grille with grid pattern and exclusive front and rear bumpers. The S4 Avant is fitted as standard with roof rails - either in anodised or black aluminium. The high-gloss package, another standard feature, contains aluminium-look roof drip mouldings and window capping strips.
Four exclusive colours make it easy to distinguish an S4 from the rest of its family at first glance: Imola Yellow, Nogaro Blue, Brilliant Red and Goodwood Green.
Carbon Atlas inlays or, as a no-cost option, inlays with a black piano finish, in silver aluminium or grey birch offer drivers the chance to customise their car's interior. S4 badges on the nose and tail, on the scuff plates, in the instrument cluster, on the dashboard and on the 3-spoke sports steering wheel clearly indicate this Audi's special status, even when stationary.
Recaro sports seats at front (with electric adjustment functions) and rear are an eye-catcher inside the S4. They provide excellent lateral support even when cornering at high speed and are also extremely comfortable on long journeys. The seats are upholstered in a cloth/leather combination as standard.
Comfort and convenience in the S4 are enhanced by numerous other standard equipment features - the deluxe automatic air conditioning with separate controls for driver and front passenger, for example. Other useful features include electric front and rear windows, radio remote control for the central locking with automatic close function and the storage package comprising cup holders, a storage net on the back of the front seats and drawers under the front seats.
All S4 models have high-intensity xenon headlights. The standard lighting package contains door lights, footwell lighting, light units on the door openers, for example, and background lighting on the centre console.
The asymmetrically split rear seat and a load-through facility with ski bag optimise the variability of the luggage compartment on both saloon and Avant models.