Audi is unveiling the top sports model in the A4 range. The current generation S4 is making its debut at the 2002 Paris Motor Show. The further developed V8 engine with chain located at the rear and with a swept volume of 4.2 litres develops 253 kW/344 bhp and 410 Newton metres of torque. As a result it sets clear benchmarks in the B segment: a benchmark for supreme, even development of power resulting from the large displacement, and a benchmark too for a new dimension in dynamic handling.
The S model tradition at Audi
The “S” models began in the 1980s when the legendary Audi quattro went from victory to victory on the world’s rally tracks. The first vehicle to bear the “S” symbol in its name was the unmistakeable S1 quattro crowned with large spoilers with which Walter Röhrl, among others, won the Pikes Peak mountain race.
More modest in appearance but nevertheless still in the sporting mode were the first Audi road vehicles that had the “S” emblem: the S2 with a five-cylinder, 2.2-litre turbo engine and 169 kW (230 bhp) based on the Coupé and the Audi 80 model line.
In the second half of the 1990s Audi then introduced several of these especially sporty top models in their respective model lines:
- the now 165 kW (225 bhp) S3
- the 195 kW (265 bhp) S4/S4 Avant (built as an Avant until 2001)
- the 220 kW (340 bhp) S6 and S6 Avant
- and the 265 kW (360 bhp) S8 (built until 2002).
All these models not only have engines that marked a major hike in power compared to their next most powerful cousins, but also quattro permanent all-wheel drive, sports suspension and sporting attributes in the interior and exterior design and the particularly extensive equipment specific to the S models.
Audi’s “S” philosophy is also derived from these properties: S models are sporting and exclusive but at the same time high-performance top versions of the individual model lines. They bring together the brand’s technical highlights - such as quattro permanent all-wheel drive, powerful engines and suspension for the optimum in dynamism - to produce a synthesis of driving enjoyment and versatility.
And they appeal to customers who do not wish to define their liking for distinctive sportiness with aggressive and obtrusive design attributes, but who prefer clear and yet discreet visual signs.
Exterior design
Superiority therefore is already expressed in the consciously restrained appearance of the new Audi S4. The body of the S4 Saloon and Avant, which is sporty in its proportions and in the basic shape, is only different in subtle ways from the other members of the model line. It is in the details that the new S4 is clearly characterised as the sports version.
A typical situation that many drivers of the new Audi S4 will find themselves in: when manoeuvring to overtake, a knowledgeable driver in front when looking in his or her rear-view mirror will see the more powerful, fully painted bumper with large air ducts, xenon headlights with contrasting titanium-coloured inner housing and polished aluminium door mirrors. The signal is clear - a special Audi model is approaching.
An awareness that is confirmed with a glance at the tail end when the S4 has driven past. Here the onlooker will notice the typically powerful exhaust tailpipes on both sides and - on the saloon version - a discreet rear spoiler as the characteristic feature of the Audi S4.
S4 models can be identified from the side by sills in the same colour as the body, contrasting door trim strips and the characteristic “S” wheels of Avus design. Large 17-inch discs at the front indicate the performance of the braking system.
The exclusive exterior paint finishes Imola Yellow, Brilliant Red, Nogaro Blue and Goodwood Green, pearl effect are available - as on the other S models - for the S4. The S4 can also be ordered in Brilliant Black, in the metallic colours Silver or Dolphin Grey and in Ebony Black or Moro Blue, both with pearl effect.
Interior design
The Audi S4 is not only notable for its sporting exterior but even more so for its inner values. This applies not only to the technology but also to the passenger compartment. The number one property of this independent top-of-the-range model is the sporting character which is clearly reflected in the original design and in the high-quality interior equipment.
The instrument cluster thus has the characteristic grey “S” dials and special needles. The leather, three-spoke sports steering wheel with the “S” emblem also emphasises the especially sporting character of the vehicle. If a six-speed tiptronic gearbox is chosen, the gears can also be changed with paddles mounted on the steering wheel - an ergonomic concept that has already proven its worth on the multiple Le Mans winner, the Audi R8, and on the Audi RS 6.
The Recaro sports seats that are electrically adjustable in eight directions provide firm lateral support as well as excellent comfort on long journeys. Not only the driver and front passenger benefit from these qualities, but also passengers on the two rear seats.
Inlays in carbon fibre (standard version) or, as an option in birch grey, aluminium grey or piano finish, are exclusive to the S4. Like the special materials for the surfaces and seat upholstery, these create accents of sporting elegance.
The S4 is equipped with a leather/cloth combination as standard; as an option a leather/Alcantara combination or the especially exclusive silk nappa leather are also available. Depending on the choice of material, the interior can be designed in various black/colour combinations or alternatively in silver, blue or dark green.
Engine and transmission: full power output
The heart of the new Audi S4 is quite clearly its engine - a newly developed V8 with a swept volume of 4.2 litres and five-valve cylinder head. This engine is notable not only for its dominant power (253 kW/344 bhp), but also at first glance for its impressive and incomparably short design.
Its dimensions - especially the length of only 464 millimetres - for the first time enable installation in what is, for a vehicle in the B segment, a very slim engine compartment.
In order to make this compactness possible, the Audi engineers have installed a chain drive for camshafts and ancillaries on the engine output side. The length could thus be reduced by no less than 52 millimetres.
The engine designers have also made a saving in terms of weight in the new engine. The weight of the pistons could thus be reduced by 70 grams for each piston to 392 grams, whilst the conrod weights have been reduced by 66 grams to 501 grams. These measures provide the basis for low frictional losses in the engine and a high maximum engine speed of 7,200 rpm.
An additional benefit: the entire V8 at only 195 kilograms total weight is just as light as its predecessor in the previous S4, a 2.7-litre V6 biturbo engine. This results in major benefits for weight balance and handling characteristics.
On the other hand, the engineers have not saved anything in terms of power. The V8’s thrust enables the new Audi S4 with 6-speed manual gearbox to sprint from 0 to 100 km/h in only 5.6 seconds. It takes just 20.6 seconds to reach 200 km/h, whilst the top speed is a governed 250 km/h.
The new 4.2-litre engine provides its maximum power of 253 kW (344 bhp) at 7,000 rpm. The maximum torque of 410 Nm is available at 3,500 rpm. Even at only 1,100 rpm the large V8 provides almost 300 Nm, and between 3,000 and just under 4,500 rpm the torque plateau is always above 400 Nm.
Clearly more impressive than such figures is the combination in practice of spontaneous response to every movement of the accelerator pedal, its astonishing free revving and the hefty torque typical of a V8. And then there is the experience of an equally characteristic V8 sound - reserved and practically free of vibration in the low speed band and with a sonorous tremolo under load - that makes no secret of the engine’s potential.
Power on the one hand and low emissions on the other are not contradictions for the Audi S4. Thanks to efficient exhaust emission control with primary and main catalytic converter it remains clearly within the EU IV limits.
The Audi S4 consumes 13.3 litres of Super Plus petrol every 100 kilometres (overall according to 1999/100 EC).
Power is transferred via a closely stepped, extremely precise 6-speed manual gearbox of the latest generation, with short sports-style shifts and quattro permanent all-wheel drive at the wheels. A 6-speed tiptronic gearbox with Dynamic Shift Program DSP and Sport program will extend the range in the second half of 2003.
Quattro all-wheel drive is a standard feature for an Audi S model. It ensures excellent traction and directional stability; and it reduces the influence of the drive forces on the self-steering characteristics to a minimum. The self-locking Torsen centre differential on the Audi S4 distributes the drive forces variably to the front and rear axle. This guarantees the best possible straight-line running, high driving stability and maximum propulsion.
Running gear
The lightweight aluminium suspension, based on the much-praised axle design of the A4 model line, provides the ideal basis for maximum agility and, consequently, sheer driving pleasure.
Four-link front suspension and trapezoidal-link rear suspension enable maximum steering precision and clearly defined handling with excellent cornering stability. Ride comfort also benefits from this ingenious axle design because a low unsprung mass also makes for a particularly sensitive response from the suspension. The wheel carriers on the new Audi S4 are also manufactured in aluminium for the same reason. Compared with conventional steel construction this means a reduction in the unsprung mass of almost two kilograms per wheel.
A general characteristic for which the A4 model line since its first appearance has already received unanimous praise in the automotive press, and which is accentuated even more clearly on this new model. Audi’s development engineers have tuned the springs, shock absorbers and anti-roll bars to improve sports performance even further. And they have lowered the chassis - and therefore the centre of gravity - by 20 millimetres.
The new S4 generation has one of the most complex and efficient rear wheel suspensions that is presently available as a standard feature: the self-stabilising trapezoidal-link rear axle, especially designed for quattro drive. Newly tuned toe-angle kinematics optimise the directional stability and the precision of the steering response even further.
Compared with the basic version, the steering of the new S4 is much more directly transferred: for the driver this is a decisive contribution to the sports-oriented handling of the agile V8 version that can be experienced in all situations. A standard feature on both the saloon and the Avant is the speed-dependent servotronic, which enables precise steering at high speeds as well as effortless manoeuvring and parking.
The braking system is also matched to the powerful potential of the Audi S4. The disc diameter of the 17-inch wheel brakes is 345 millimetres at the front and 300 millimetres at the rear. The system is operated via a new dual-rate servo. This gives the driver a sporty, firm pedal feel in the low to medium deceleration range whilst at the same time providing exceptional control of the brake force.
In the comfort braking range of up to around 0.5 g deceleration, the brake servo’s ratio at factor 5.5 is at the level of the other A4 models and thus ensures especially good control. Above 0.5 g the ratio is raised to the factor 12. In this way, the deceleration increases disproportionately high to the braking force - a clear advantage for a sporting style of driving. The S4 achieves full deceleration with comparably low pedal force and with less pedal travel than on a conventional system.
The Electronic Stabilisation Program ESP 5.7 including hydraulic brake assist ensures active driving safety.
The Audi S4 will roll to the start on standard 18-inch wheels. The tyres for these alloy wheels are of size 235/40 R18.
[source: audi-mediaservices.com]
Pictures from Paris Motor Show:
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