Audi S4: Re-Charged

Motoring Channel Staff - 1/October/2008

Ingolstadt, Germany — The approach is new, but the intent remains the same: high performance in a luxurious package.

Audi's all-new S4 model will be launched at the 2008 Paris Motor Show, in both sedan and wagon variants, and waves goodbye to the famed V8 powerplant.

The German car maker has ditched the 4.2-litre V8 engine from its go-fast S4 model, replacing it with a 3.0-litre supercharged V6 engine kicking out 245kW.

While the engine may have dropped a couple of cylinders and lost displacement with the introduction of this all-new model, Audi claims the new S4 (wagon and sedan) is both faster and more fuel efficient thanks to the forced induction and direct fuel injection.

Using supercharging, or "mechanical charging" as Audi calls it, alongside its FSI direct injection system is "far superior to twin turbochargers, both in terms of packaging and of starting performance and responsiveness".

Read between the lines in that excerpt from the press release and Audi is denigrating BMW's impressive 335i which we have road tested, and which will be the Audi S4's main rival (the BMW also uses a 3.0-litre 6-cylinder engine - albeit with twin turbos instead of a single supercharger).

Based on the new Audi A4 platform, the S4's advancements centre on the powerful new engine, but upgraded sports suspension, stronger brakes, high traction tyres and performance interior fittings such as sports seats and pedals add to the S4's appeal.

Ingolstadt's new mean machine also has a few subtle exterior upgrades, including large-ish 18-inch alloy wheel rims, a lower ride height and ground effects body work.

Like all modern Audi products, the S4's front end has a stylish design with good attention to detail. 

The chrome single frame grille is flanked by boxy headlight lenses that feature swooping LED driving lights that integrate around the projector beam headlights.

Quad exhaust pipes and grey inserts add a bit of sportiness to the car's back end and there's also the obligatory chrome wing mirrors that denote Audi's high performance models.

The 3.0-litre (2,995cc) supercharged V6 engine flies in the face of convention: almost all modern European engines with forced induction today are turbocharged. 

Even Mercedes and its performance partner AMG have begun switching from superchargers to turbochargers. 

For Audi however, playing follow-the-leader is not part of its long-term game plan.

The new engine outputs 245kW (333hp) which is 5 kilowatts more than its biturbo BMW rival.

Using a belt-driven supercharger that starts developing charge boost at idle, the engine belts out 440Nm of torque @ 2500, and has a flat torque curve all the way until 4850rpm and keeping the torque output constant.

The supercharger itself is small and Audi was able to place it in between the (90-degree vee) cylinder banks. 

The supercharger is plumbed to a pair of intercoolers ('charge air coolers' in Audi lingo) and under full throttle and in ripe conditions, Audi claims the S4 sedan will accelerate from zero to 100km/h in 5.1 seconds. 

This is fast enough to upset Japanese giants such as the Subaru WRX STI and Mitsubishi Evolution, but the Audi S4's appeal is that it doesn't have a an overt appearance.

Power is put to the ground via either a 6-speed manual transmission or a new 7-speed S tronic twin-clutch gearbox, and is transferred through all four wheels thanks to Audi's proprietary quattro system.

While the 7-speed semi-auto gearbox results in faster acceleration and improved drivability in the city and commuter traffic, the manual will still garner a few sales with performance die-hards who plan on modifying the tantalising new intercooled six.

Though it can trounce many other performance cars, the S4 can blend in to the crowd which is an aspect of the vehicle that will appeal to more mature drivers.

Called the 3.0 TFSI, the new engine provides the S4 with excellent acceleration but one of the reasons Audi switched from the 4.2-litre V8 to the 'charged 3.0-litre V6 was to meet future emission restrictions and to reduce fuel economy.

Audi claims the new S4 uses an average of 9.7 litres of fuel per 100km travelled, which is quite low for a performance car of this capability, which can reach speeds of up to 250km/h.

The new Audi S4 is a bold shift for the German automaker, using a new type of engine to achieve high power and fuel efficiency, and the move could reap big rewards for Audi.

Approaching its high performance sports cars from a different angle, Audi appears to have yet again set the trend.

Launching at the 2008 Paris Motor Show, the new model is set for a European launch in the first quarter of 2009, and is expected in Australia six months after that.

Related Links:
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- Audi RS6 Sedan (2009)
- Audi A6 (2009)
- Audi A5 (Road Test)
- Audi Vehicle Schedule Leak (2010)
- Audi TT Clubsport quattro (2008)
- Audi A3 Clubsport Quattro concept (2008)
- Audi S3 (Road Test)
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- Audi Metroproject quattro Concept (2009)
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- Audi S8 (Road Test)
- Audi Q5 (2009)