- Supercharged V6 engine delivers performance
- Traction from quattro system contributes to excellent dynamics
- High standard of interior fit and finish
- Stering lacks feel and is heavy at low speeds
- Lacks driver involvement
- Optional sports differential should have been standard
Review: Audi B8.I S4 (2009-12)
Overview
Released in June 2009, the Audi B8 S4 was a compact executive, sports sedan. Manufactured in Ingolstadt, Germany, the Audi S4 was powered by a 3.0-litre supercharged V6 petrol engine that was mated to a seven-speed double clutch transmission (Audi’s ‘DSG’) that drove all four wheels via Audi’s ‘quattro’ system.
3.0 TFSI V6 engine
The S5 Sportback’s 3.0-litre CAKA TFSI V6 engine had an aluminium-silicon alloy crankcase, a die-forged steel crankshaft, a cast aluminium cylinder head, chain-driven double overhead camshafts, variable intake camshaft timing over a range of 42 degrees, four valves per cylinder (including chrome plated exhaust valves with sodium-filled stems), direct fuel injection (Audi’s ‘Fuel Stratified Injection’ or FSI) and a compression ratio of 10.3:1.
The 3.0 TFSI V6 engine featured a Roots-type positive displacement supercharger – produced by Eaton – that was positioned in the ‘V’ of the cylinder banks. The supercharger had twin four-lobe rotors and could force intake air into the combustion chambers at a maximum boost pressure of up to 0.8 bar.
| Engine | Trans. | Peak power | Peak torque | |
|---|---|---|---|---|
| S4 | 3.0-litre CAKA supercharged petrol V6 | 7sp DCT | 245 kW at 5500-7000 rpm | 440 Nm at 2900-5300 rpm |
Dimensions and suspension
Compared to the Audi B7 S4 , the B8 S4 was 131 mm longer (at 4717 mm), 45 mm wider (1826 mm), 9 mm lower (1406 mm) and had a 160 mm longer wheelbase (2811 mm). Like the Audi B8 A4 , on which it was based, the S4 had five-link front suspension with unequal length wishbones and self-tracking trapezoidal rear suspension. Relative to the A4, however, the S4 had firmer shock absorber settings, stiffer bearings for the controls arms and the body was lowered by 20 mm.
quattro
The Audi B8 S4’s quattro four-wheel drive system consisted of a Torsen T3 differential which provided a default 40:60 front:rear torque split. If traction was lost, up to 80 per cent of the engine’s torque could be directed to either the front or rear axles. The system also included an open front differentials with an electronic differential locks which could brake a spinning wheel to enable cross-axle torque transfer. The B8 S4 also introduced a torque vectoring rear axle which operated by selectively distributing torque to the rear wheels to generate yaw and thereby correct over- or under-steer.
Safety equipment
Standard safety equipment for the B8 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 B8 S4 had ventilated front and rear disc brakes, measuring 345 mm at the front (diameter) and 330 mm at the rear.
Features: B8 S4
Standard features for the Audi B8 S4 included 18-inch ‘S-design’ alloy wheels, a ten speaker stereo with a six-disc CD player, MP3-compatibility and auxiliary inputs, satellite navigation system, dual-zone climate control air conditioning, power adjustable front sports seats, leather seat trim, cruise control, directional bi-xenon headlights with LED running lights, front and rear fog lamps, front and rear parking sensors, automatic headlights, rain-sensing wipers, a leather-wrapped steering wheel with gearshift paddles, Bluetooth connectivity with voice recognition, remote central locking with proximity key, power windows and heated mirrors, a power-operated park brake, tilt and telescopic steering wheel adjustment, tyre pressure monitoring, ambient lighting, 12 volt power outlets, a trip computer, an alarm and immobiliser.
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Review: Audi B8.II S4 and S4 Avant (2012-15)
Overview
Released in July 2012, the Audi B8 Series II (B8.II) S4 range was expanded to include the S4 Avant (wagon). Visually, the B8.II S4 could be identified by its new bumpers with angular air inlets, revised headlights, flat front fog lights, more pronounced bonnet arches and tapered grille corners. Inside, the Multi Media Interface (‘MMI’) controls were revised for greater ease of use.
Compared to its B8.I predecessor, the B8.II S4 achieved significant fuel economy improvements due to the introduction of:
- a ‘start-stop’ system which could shut down the engine when stationary in traffic;
- a recuperation system which converted kinetic energy into electrical energy when the vehicle was coasting or braking; and,
- a new electrochmechanical power steering system.
| Engine | Trans. | Peak power | Peak torque | |
|---|---|---|---|---|
| S4 and S4 Avant | 3.0-litre CGWC supercharged petrol V6 | 7sp DCT | 245 kW at 5500-7000 rpm | 440 Nm at 2900-5300 rpm |
Safety equipment and features
Compared to its B8.I predecessor, standard safety equipment and features for the B8.II S4 sedan were largely unchanged. Compared to the sedan, the S4 Avant was further equipped with aluminium roof rails and a power-operated tailgate.
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