Audi S4
Audi's quattro four-wheel-drive system was standard on the C4 S4/S6; a first-generation Torsen-based system which used the "T-1" automatically biasing centre differential (ATB) was used on vehicles equipped with manual transmissions, while a transfer box based system was used on vehicles equipped with an automatic transmission.
Audi S4
At the heart of the B8 S4 powertrain is an all-new, all aluminium-alloy 3.0-litre TFSI Supercharged (TFSI) V6 engine (parts code prefix: 06E, identification code: CAKA), and like the rest of the B8 model range, now with Fuel Stratified Injection (FSI). This petrol engine displaces , and it is rated by Audi to a power output of from 5,500 to 7,000 rpm. Torque is rated at from 2,900 to 5,300 rpm. This high power output is achieved by using forced induction – and specifically, an all-new Eaton 'Twin Vortices Series' (TVS) Roots-type positive displacement compressor. This new supercharger features twin four-lobe rotors, which are axially twisted 160 degrees. It is mounted on top of the engine, within the 'Vee', pumping air directly into the inlet manifold, and incorporates two separate water-cooled intercoolers. This new design of supercharger is said to reduce the noise, vibration, and harshness (NVH) of the engine.