Audi Ups Ante with Bahnstorming RS 4

Motoring Channel Staff - 6/9/2005

Audi's answer to the venerated BMW M3 has arrived in the form of the all-new RS 4, the most potent A4 derivative the German company has ever created.

As with all RS models from the Audi stables, prerequisite features such as quattro AWD, huge brakes, grippy wheels and a luxury-sports interior feature prominently.

But topping the list of motorsports-derived equipment is the new RS 4's core: a devastating 4.2-litre V8 engine.

With a rev ceiling that would instil envy in some motorcycles, the new highly strung V8 engine will spin to 8250rpm and propels the welterweight German sportscar to 100km/h in just 4.8 seconds.

Created by Audi subsidiary quattro GmbH, the new RS 4 features subtle bodywork, which accentuates the A4's already contemporary lines. Flared wheel arches allow ample space for the big 18-inch alloy wheels (equipped with 255/40 R18 tyres), which do little to hide the vehicle's potential to grip the road, and also increase the car's track.

Deep front and rear aprons with exaggerated air dams guarantee optimum cooling of the V8 FSI engine, and a twin-chamber exhaust system with oval tailpipes lend the car a neat and sporty character at the rear.

Other exterior updates for the RS 4 include tastefully flared side skirts (plus door cut-out trim strips matched to the skirts), a rear spoiler integrated in the boot lid and aerodynamically optimised twin-arm design RS exterior mirrors.

Despite this uncompromising sportiness, the car's close family relationship with the Audi A4 is unmistakable. The distinctive single-frame grille and the sweeping headlights, borrowed from the Nuvolari prototype, underscore the family heritage of the RS 4.

The RS 4 is lowered a further 30 millimetres over its A4 siblings, adding to its sporty look, but also increasing levels of driving dynamics the car offers.

Another boon for the RS 4's handling characteristics is the revised quattro 4WD system, which apportions torque between the front and rear axles in a 40:60 ratio, giving the car a rear wheel drive bias. This latest generation of Audi's permanent four-wheel drive offers an asymmetric/dynamic torque distribution ratio as mentioned, plus a self-locking Torsen centre differential.

Audi asserts that it's quattro technology still provides traction when other drive concepts have long since reached their limits, and in 2006 the quattro drive system will be further enhanced by DRC (Dynamic Ride Control) which significantly reduces both the rolling and pitching motions of the vehicle when it corners and accelerates/decelerates.

The brakes, too, represent new dimensions in their innovation. The perforated ventilated brake discs at the front measure a very large 365 millimetres in diameter, with similarly perforated ventilated brake discs at the rear in 324mm diameter. Flow-enhanced ventilation geometry incorporating NACA jets on the underbody of the car ensures optimum cooling of the brakes. As a result, brake fading is significantly reduced even under extreme loads, such as on the race track.

The latest generation of ESP has been modified specifically to suit the special properties of the high-performance RS 4. Its interventions are now later and shorter. It is also possible to disable the ESP in two stages. In the first stage only the traction control (ASR) function is disabled; the other ESP functions remain fully active. In the second stage the ESP is completely deactivated, including the traction control. All electronic control then ceases.

Numerous technical innovations – many of which hail from motorsport – give the new Audi RS 4 its unique character, and one of these features is the high-revving V8 FSI engine. Developing a maximum output of 313kW (420hp), the V8 revs up to a speed of 8250rpm.

With its displacement of 4,163cc, this outstanding engine breaks through the magic barrier for a production saloon of 100 horsepower per litre and will surely give the BMW M3 a royal headache. The highly compact power unit reaches its peak torque of 430Nm @ 5500rpm, and Audi says that 90 percent of the total torque is available between 2250 and 7600rpm.

The RS 4 saloon employs groundbreaking FSI technology, or fuel stratified injection. Essentially a petrol direct-injection system, the new 4.2-litre unit delivers enhanced power output based on more efficient combustion of the fuel/air mixture.

New features of the 8-cylinder unit powering the RS 4 include modified pistons and conrods, a new crankshaft together with its bearings, and new cylinder heads.

A twin exhaust system with enlarged pipes provides even higher power output, and makes for an incredibly responsive powerplant: it reaches the 100km/h mark in 4.8 seconds, and 200km/h in 16.6 seconds, and like all German super saloons top speed is limited electronically to 250km/h.

The car's prodigious torque levels are transferred to all four wheel via a 6-speed close ratio manual transmission, and addition cooling fins have been fitted to the rear axle differential, in response to the high loads to which the RS 4 may be subjected. No DSG (direct shift gearbox [twin clutch]) option has been talked about yet, but could be introduced at a later date to combat BMW's SMG-equipped M3 and M4 models.

Another key requirement for the RS 4's developers was an optimum power-to-weight ratio. Practically every part was checked in terms of its weight: the front quarter panels and the bonnet are made of aluminium, as are most of the chassis components. The specially designed RS bucket seats are not only very light, but also offer excellent body support.

The result is a power-to-weight ratio of just 3.93 kilos per bhp – a sports car-like accomplishment which would have been inconceivable for a mid-size saloon just a few years ago. Compared to the current model M3, the new RS 4 is quite a bit more powerful, but the new M3/M4 due to be released at the 2005 Frankfurt Motor Show should even the odds.

Inside, the RS 4 combines the functionality of a sports car with the luxurious ambience so typical of all Audi models. Leather, aluminium, and carbon are the predominant materials. But at the same time the RS 4 comes with all the additional qualities typical of a genuine sports car.

This becomes clear as soon as you sit in it. The RS bucket seats, with their high side sections, offer firm hold. They also have an additional feature. By pressing buttons on the seat the side sections can be inflated to mould perfectly to the driver's anatomy. The flat-bottomed RS sports steering wheel and the engine start button on the centre console are also clearly reminiscent of motorsport, as are the aluminium pedals.

There's even a 'Sport' button on the steering wheel that can deliver an even more dynamic performance when required. The accelerator characteristic changes progressively, so the engine is perceived to respond sooner. The sport model also engages a flap in the exhaust system that opens to provide the RS 4 with an even sportier sound.

Beyond all the motorsports-inspired fittings - the insane 300kW+ engine, the massive brakes, the Dynamic Ride Control and the 40:60 torque split - Audi has ensured that occupants are well taken care of - the RS 4 therefore comes with virtually all the features already boasted by the Audi A4.

Apart from a wide range of safety components, this also means deluxe automatic air conditioning, central locking with remote control and electric front windows. Further features of the RS 4 include the Audi parking system at the front and rear, the concert radio system, while options such as the Audi navigation system plus or the adaptive light dynamic cornering lights can also be factored in, providing for what may well be the ultimate European luxury super sports saloon.