- Free-revving V8 engine sounds great
- Traction from quattro system contributes to capable dynamics
- Supportive front seats
- High standard of interior fit and finish
- Suspension lacks compliance
- When pushed, nose-heavy body produces understeer
- Instruments difficult to read
- Limited rear seat room
Overview
Released in December 2003, the Audi B6 S4 was initially available as a sedan, with Avant (wagon) models following in August 2004. Manufactured in Ingolstadt, Germany, the Audi S4 was powered by a 4.2-litre V8 petrol engine that was mated to either a six-speed automatic or manual transmission and drove all four wheels via Audi’s quattro system.
4.2 V8 engine
The Audi B6 S4’s 4.2-litre BBK V8 petrol engine had a cast aluminium alloy block, die-forged steel crankshaft that operated on five main bearings, a cast aluminium alloy cylinder head, double overhead camshafts per cylinder bank (chain-driven), five valves per cylinder actuated by roller rocker cam followers, variable intake camshaft timing, a variable intake manifold, a compression ratio of 11.0:1 and maximum engine speed of 7200 rpm.
Although based on the AQH/AVP/AYS/BCS engines in the Audi D2 S8 , the length of the BBK engine was reduced by 52 mm to 464 mm so that it could fit in the engine bay of the Audi B6 S4. This reduction in length was achieved by transferring the chain drive to the clutch side of the engine and using chain-driven camshafts.
With the six-speed manual transmission, the S4 sedan could accelerate from rest to 100 km/h in 5.6 seconds.
| Years | Engine | Drive | Trans. | Peak power | Peak torque | |
|---|---|---|---|---|---|---|
| S4 | 2003-05 | 4.2-litre BBK petrol V8 | quattro | 6sp man., 6sp auto | 253 kW at 7000 rpm | 410 Nm at 3500 rpm |
| S4 Avant | 2004-05 |
Dimensions and suspension
Compared to the Audi B5 S4 , the B6 S4 sedan was 63 mm longer (at 4546 mm), 33 mm wider (1766 mm), 32 mm taller (1428 mm) and had a 30 mm longer wheelbase (2645 mm). Furthermore, the B6 S4 Avant had the same dimensions as the B6 sedan. The B6 S4 and S4 Avant had four-link front suspension with unequal length wishbones and self-tracking trapezoidal link rear suspension.
quattro
The Audi B6 S4’s quattro four-wheel drive system consisted of a Torsen T2 centre differential. In normal conditions, the system provided a 50:50 front:rear torque split but up to two-thirds of the engine’s torque could be directed to either axle if traction was lost. The system also included open front and rear differentials with electronic differential locks which could brake spinning wheels to enable cross-axle torque transfers at speeds of up to 80 km/h.
Safety equipment
Standard safety equipment for the Audi B6 S4 included dual front airbags, front and rear side airbags, full-length curtain airbags (i.e. for front and rear occupants), ABS, electronic brake force distribution, brake assist, electronic stability control, traction control and front seatbelts with pretensioners and load limiters.
Brakes
The Audi S4 had radially ventilated front and rear disc brakes; the 345 mm (diameter) by 30 mm (width) front discs and 300 mm by 22 mm rear discs were both fitted with single-piston sliding calipers.
Features
Standard features for the Audi B6 S4 included 18-inch Avus III alloy wheels with 235/40 R18 Y Contintental tyres, a ten speaker stereo with a 10-disc CD changer, dual-zone climate control air conditioning, combination Alcantara/leather upholstery, power adjustable Recaro front seats, xenon headlights with washers, front and rear fog lights, rear parking sensors, automatic headlights, a leather-wrapped steering wheel, split and folding rear seats, remote central locking, power windows and heated mirrors, tilt and telescopic steering wheel adjustment, an alarm and an immobiliser.
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