The 3.0 TFSI is the new range-topping unit in Audi's V6 engine family. It Develope 333 horsepower and 324 lb-ft (440 Nm) of torque at 2,500 rpm, the engine is connected to either a standard six-speed manual gearbox, or an optional seven-speed, dual-clutch transmission which can be used either as a conventional automatic or as a sequential semi-auto with steering wheel mounted paddles.
Now the supercharger is staging a comeback - the T in the engine description no longer stands for the turbocharger alone. Extensive comparative tests revealed the mechanical supercharger to be superior to a biturbo concept for the big V6 engine. In conjunction with direct injection this concept has clear advantages in terms of the prioritized features of packaging, starting performance and responsiveness.
The seven-speed S-tronic gearbox of the 2009 S4 consists of two separate transmissions and uses two multidisk clutches that control the various gears. The large K1 clutch guides the power via a solid shaft to the pinions for gears 1, 3, 5 and 7. A hollow shaft rotates around the solid shaft; it is connected to the compact K2 clutch, which is integrated within its larger counterpart and controls the pinions for gears 2, 4, 6 and reverse gear.
Both transmission structures are continuously active, but only one is powered at a time by the engine. The quattro all-wheel-drive system sends power to all four wheels. A 40/60 percent front/rear torque bias ensures that the handling remains sporty yet stable. However, when necessary, the power distribution can be varied within fractions of a second.
The 2009 Audi S4 shares the same styling cues as the rest of the model lineup. Some of the most striking modifications to the exterior design are the special aprons, the aluminum-look exterior mirrors, the 18-inch S-design light-alloy wheels, the side rocker panels, the discreet rear spoiler and the quadruple exhaust system. The xenon plus headlights with daytime running lights and the rear lights are further distinctive touches.