Audi RS 4 Saloon

by David Finlay (5 May 2006)

If I met the people behind the RS 4 I would find myself expressing envy and admiration in equal measure. What luck to have been chosen for the project to turn the A4 into a supercar; and what a truly fantastic job they all did. I believe I can say, with only a couple of small reservations, that this is one of the very finest high-performance saloon cars I have ever driven.
Having lived with the RS 4 saloon for a week (there are Avant and Cabriolet versions too) there are several aspects that continue to inspire wonder. Which of these is the most impressive? The 414bhp 4.2-litre direct-injection V8 engine is an early candidate, for sure. Until recently, coaxing that amount of power from that capacity while still retaining some semblance of road manners would quite certainly have demanded the use of at least one turbocharger. But the RS 4 has none. Can you not share my amazement that this unit produces so much power, and with such refinement, while being left to breathe in air without external assistance?
To produce a lot of power, an engine needs either a lot of torque or the ability to reach very high revs. By abandoning turbocharging, Audi has had to focus on engine speed, with the result that the RS 4 tops out at what is, for a 4.2-litre road car, an astonishing 8250rpm.
Once again, it's not that long since a statistic of this kind would have implied feeble low-rev performance. The RS 4 obliterates that justifiable prejudice too. Maximum torque of 315lb/ft may not seem like much compared with the power figure, but it's still a lot - and, more importantly, 90% of it (or about 280lb/ft) can be accessed all the way from 2250 to 7600rpm. Even without the standard close-ratio six-speed gearbox, it's difficult to imagine this car ever failing to pull strongly when asked to perform.
So much for the figures. In real life, what happens is this: you floor the throttle at almost any speed, and the RS 4 leaps forward with a slightly muted but none the less evocative eight-cylinder roar. If you're in second gear at the time, you're soon doing 70mph; if in third, 100mph is not far away. In more subtle motoring, slight pressure on the accelerator pedal is enough to keep you travelling at speeds which would require outstandingly more effort in nearly every other saloon car you can buy.
This is, in short, an extraordinary engine. But as far as I'm concerned it is not, despite all of the above, the thing which truly defines the RS 4. Nor are the huge brakes which lurk under the wheels and cope so easily with deleting the kinetic energy which the engine bestows on the rest of the car. No, the single most outstanding feature of the RS 4 is, to me, the absolutely extraordinary level of grip.
The suspension engineers had a head start here, of course. Audi has used (it's beyond conceiving that it would not have used) its quattro four-wheel drive system. Up to 414bhp is produced at the engine's flywheel, and quite a bit of it is absorbed in the transmission. Each wheel, or rather each tyre - and these are hugely sticky 255/35x19 Pirellis we're talking about here - therefore has to cope with a good deal less than 100bhp. On top of that, the suspension is set up surprisingly softly (even if the amount of road information transmitted by those low-profile tyres might persuade you otherwise) which further helps to maintain grip.
Starting from these helpful principles, the engineers have contrived a suspension system which works quite beautifully. The only thing which rained on their parade was the A4's basic nose-heaviness, which the best suspension work could not fully disguise. Because of the forward weight bias, the RS 4 occasionally struggles with sudden bumps or camber changes, and there are a few hints that on a race circuit the limiting factor would be understeer. For these reasons the car does not have quite the painted-on-the-road feel of, for example, a Mitsubishi Evo IX, though it's fair to point out that the Audi has a certain serene quality which no Evo could hope to match.
In all other respects the RS 4's handling is extraordinary. Tight uphill corners which, in almost anything else, would require a brake and a change down to third can be taken in sixth without so much as a lift. This is not a recommendation to drive crazily, but it is an attempt to explain what the car can achieve with the absolute minimum of fuss.
A good test of a great high-performance road car is whether or not it can be driven slowly. The RS 4 deals easily with gentle motoring, to the point where you can leave it in top gear while the engine speed dips to as little as 1000rpm. But that's not to say the driver is necessarily as comfortable with the process as the car is.
The first few minutes of the experience can be a little intimidating. First you notice the tough ride (though you can specify that out of existence to some extent - larger-profile tyres on smaller wheels are a no-cost option). Then you discover that the RS 4 expects to be treated quite firmly. Fast responses of the steering, throttle, brakes, gearbox and clutch - whether engaging or disengaging - can be unsettling when only slow responses are required; it's much easier to be smooth when you're going quickly, particularly when you're firing from one gear to another, than it is to achieve the same goal in stop-start urban traffic.
There are some unusual touches, and some bizarre ones too. As standard, the RS 4 has a Sport button on the steering wheel which performs three functions. One is to improve throttle response, though the difference between the two settings is minimal. The other is to change the exhaust note, and this is, along with the F1-inspired flattened bottom of the steering wheel itself, one of two surprisingly frivolous aspects of an otherwise deeply serious car.
The third function is to make the driver's seat fold round its occupant, pinning him or her securely into place. I can see the value of this on a track day, but perhaps not so much for road use, since in those circumstances there is already an almost unparallelled amount of body support. If your own body happens to be above-averagely large, it might be best to leave the Sport button alone in the interests of maintaining blood circulation.
The other thing to note about the front seats is that they are very large, reducing legroom for rear passengers almost to zero. The backings to those seats are tough, unyielding and convex, so clearly Audi has biased the interior towards the interests of those who sit ahead of the centreline.
Our test car had £3325 worth of options, namely DVD-based satellite navigation, a TV receiver, a 6-CD autochanger and adaptive headlights (excellent units which follow the steering smoothly, rather than in the abrupt shifts you find in cheaper cars). It did not have the Sport Suspension Plus pack, which for £500 provides firmer springing and damping along with a 10mm reduction in ride height.
I'm not sure I'd want it. I could live with the standard ride, but anything harder might quickly become unpleasant. And although the pack might send the cornering limits even higher, how could you possibly make use of that? In the form as tested here, the RS 4 is magnificent, and needs nothing more than the engine being moved back a foot (how much easier, unfortunately, to say than do) to become a work of genius.

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