New European S4 news

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03-09-1999, 08:51 AM

Matt Daniels

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New European S4 news

AUDI AG Public Relations Communication: Product and Technology D-85045 Ingolstadt Tel.: +49 841 89-32100/-37947 Fax +49 841 89-32817 March 1999 Sporty - Powerful - SuperiorAudi S4/S4 AvantThe Audi S4 and S4 Avant are a synthesis of well-proven features such as quattro permanent four-wheel drive, and new elements such as the powerful V6 twin-turbo engine with its impressive performance figures. The overall impression is one of restrained superiority at all times.These cars can trace their lineage back to such motor sporting legends as the striking original quattro, the Sport quattro S1, a car designed for rally success and twice winner of the Pikes Peak race, and the super touring car championship A4 quattro with its impressive tally of seven concept that perfectly combines superior performance with masterfully understated appearance, without sacrificing everyday practicality. This is achieved without forcing the engine designer's hand. A glance at the performance figures for the new 2.7-litre V6 engine with its two small turbochargers that cut in smoothly when needed is enough to show what a superior impression the S4 is capable of making. This power unit, with five valves per cylinder, delivers its maximum output of 195 kW (265 bhp) at just 5,800 rpm. The shape of the torque curve expresses its supreme character even more clearly. 400 Nm of torque are available over a broad engine-speed range stretching from 1,850 to 3,600 rpm.Using smaller turbochargers but fitting one to each bank of cylinders instead of a single larger unit has clear advantages with the V6 engine. The more rapid response of the smaller turbines leads to the desired high torque values even at low engine speeds. Thanks to their lower inertia, the engine responds more readily to rapid pressure on the accelerator. The short distances between the cylinder exhaust ports and the turbocharger inlets mean that the exhaust gas loses less momentum and charging efficiency is thus increased.Each bank of cylinders has an intercooler which reduces the temperature of the intake air. Efficient cooling of the charge air is crucial to the forced aspiration principle: the cooler the air, the higher its density and the more oxygen is available for combustion. With cooled air, therefore, it is possible to achieve even higher engine efficiency.The special shape of the inlet ports, which creates a tumbling motion in the charge as it enters the combustion chamber, also helps to make combustion cleaner and more efficient. The optimum swirl imparted to the fuel-air mixture by this tumble effect improves the combustion process and thus has a positive effect on engine efficiency.The intake camshafts for the two five-valve cylinder heads are hydraulically adjustable to permit optimisation of the torque curve. These adjustments to the valve timing increase torque by about ten percent in the low and medium engine-speed ranges.The bare figures for the S4 and S4 Avant translate into impressive performance: the saloon takes just 5.7 seconds to accelerate from 0 to 100 km/h, and there may just be enough time to blink before the S4 Avant gets there too - 0.1 of a second later to be precise. In both cases, top speed is governed to 250 km/h. Consumption figures of 11.3 and 11.4 litres per 100 km respectively (93/116/EU overall consumption, saloon and Avant) illustrate just how efficient the engine is. Exhaust-gas temperature control, employed here for the first time, leads to more efficient use of the fuel and lower emissions. Fitted with the latest-generation engine management system, this power unit meets the strict requirements of the D3 standard in full.The power of the V6 twin turbo is converted reliably and effectively into traction by the 6-speed sports-ratio gearbox and permanent four-wheel drive. The aluminium suspension, available on the S4 from February 1999, has a noticeably positive effect on handling. In addition to all control arms in the four-link front and double wishbone rear suspension, all swivel bearings are now made of aluminium as well. The brake system has also been upgraded to match this surging forward thrust: large ventilated disc brakes front and rear with aluminium brake calipers ensure optimum braking performance. On the Audi S4, the anti-lock braking system (ABS) and electronic brake pressure distribution system (EBD) are under the overall control of the Electronic Stability Program (ESP). This makes both the saloon and the estate version two of the safest high-performance cars on the road, a fact that should do no harm to their already high popularity ratings.On the outside, the differences between the S4 and the basic A4 amount to no more than a few functionally-based design features. The new model's powerful appearance is also partly due to its sports suspension, with wide 225 tyres and 17 inch "Avus" alloy wheels.Large air intake openings give a more emphatic look to the front end of the car. The headlights with their xenon dipped beams and clear glass covers also contribute to the sporty appearance. The car is equipped with automatic beam angle control and high-pressure headlight cleaning jets.Inside, the S4 and S4 Avant have remained true to the restrained style so typical of Audi's S models. High-quality Jacquard Satin seat covers and door trim in either onyx or shell grey are standard. There is a choice of carbon or aluminium with diamond silver finish for the trim strips on the dashboard and doors. Those who like a little extra luxury can choose between elegant silk nappa leather in onyx, shell grey or silver or a combination of blue Alcantara and onyx-coloured leather.It only remains to point out that the update on the A4 also extended to the S4 saloon and Avant. The careful detail work involved has produced impressive results here too. In addition to slight external modifications such as wider side protection strips and modified rear lights, experts will also detect the new lighting concept inside the car. The interior lights have been relocated to the centre of the car to make room for the SIDEGUARD head-level airbag system that is now available as an optional extra on the S4.A new item on the optional extra list are the aluminium outside mirrors already familiar from the Audi S8, adding another distinctive touch to the already sporty silhouette of the S4. The equipment and data specified relate to the model range available in Germany. We reserve the right to make changes. Errors and omissions excepted.

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