Audi supercharges all new S4

If you’re looking for a new mid-size saloon, or estate for that matter, that can take you from rest to the legal speed limit in a shade over five seconds, while using less than 10 litres of fuel per 100 kilometres—and let’s face it, who isn’t—then Audi have the car for you. The all new Audi S4. Powered by a brand new 3-litre V6 engine, it puts out bona fide performance all of its own, while whetting the appetite for the next gen RS4. Just don’t bother trying to work out what TFSI stands for. Back in the day it meant Turbo Fuel Stratified Injection, but now, in this world of “mehcanical turbo charging”—yes that’s it, what you and I call super charging—it is probably best just to leave it to Audi to define. The addition of the blower helps the new V6 produce the very respectable numbers of 245kW/440Nm.

You may have guessed that AUSmotive is generally a fan of all things Audi, and the new S4 is no exception. Due for its first public reveal at the Paris Motor Show in a couple of weeks I can’t wait until I can get my own eyes on one when they arrive down under in the latter half of 2009.

More pics and details below. As always, click on each image for larger versions.

The New Audi S4 / S4 Avant

• Three-litre V6 unit generates 245 kW
• Acceleration from 0 to 100 km/h in 5.1 seconds
• Average fuel consumption of just 9.7 litres

Ingolstadt … Audi is introducing its new sporty top models in the midsize class – the S4 and the S4 Avant. Their engine, a three-litre V6 with direct fuel injection and mechanical turbo charging, delivers a powerful 245 kW. It accelerates the S4 to 100 km/h in just 5.1 seconds, but on average only uses 9.7 litres of fuel per 100 km. The quattro permanent all-wheel drive system transfers its power to the road in style, which is then converted by the sport suspension into dynamic handling.

Upon request, Audi can equip the new S4 and S4 Avant with innovative technologies that further increase their lead over the competition. The seven-speed S tronic changes gears with lightning speed, and the new sport differential distributes the torque as needed between the rear wheels. The new Audi S4 will be unveiled to the public for the first time at the Paris Auto Show from October 2 to 19.

The heart of the new S4 and S4 Avant is a completely redesigned engine. The 3.0 TFSI, the newest member of the Audi V-engine family, is an outstanding example of how the brand with the four rings blends performance and efficiency.

The V6 generates its power from a displacement of 2,995 cc, is equipped with a supercharger, and delivers 245 kW. The sedan sprints to100 km/h in just 5.1 seconds, and the Avant in 5.2 seconds: they both have an electronically governed top speed of 250 km/h.

The “T” in the 3.0’s TFSI nomenclature no longer merely stands for “turbo”, but rather for the concept of supercharging in general – extensive testing on the big V6 has proven the superiority of mechanical charging. In conjunction with direct injection it is far superior to twin turbochargers, both in terms of packaging and of starting performance and responsiveness.

The compressor is so compact that it easily fits inside the 90-degree V of the cylinder banks, in place of the intake manifold. Two four-vane rotary pistons counter-rotate inside the turbocharger at up to 23,000 rpm. Two charge-air coolers are integrated into the housing and are connected to a separate coolant circuit. An impressive array of measures keeps the noise generated by the compressor to a minimum.

The engine-driven belt that powers the mechanical charger provides full thrust right from idling speed. The 3.0 TFSI delivers its maximum 440 Nm at 2,500 rpm and maintains this constantly until 4,850 rpm. In fourth gear, the vehicle accelerates from 80 to 120 km/h in just 4.4 seconds. Thanks to the extremely short gas paths, the sonorous, supercharged V6 responds spontaneously to the throttle, even more so than a naturally aspirated engine of the same displacement.

Furthermore, the new 3.0 TFSI achieves exemplary fuel efficiency. On average, the sedan uses 9.7 litres of fuel per 100 km, and the Avant 9.9 litres per 100 km – an improvement of 3.4 litres (26 percent) compared with its predecessor. The Audi technology of gasoline direct injection was what made this great efficiency possible in the first place.

Unlike conventional concepts, it allows the compressor to be located behind the throttle valve. In view of the low density of the intake air at loads below supercharging level and when coasting, its rotors are free-running and the amount of power required to drive them is low.