[achien]

Audi well-armed in the four-door sport war
2008 Audi RS 4 4.2
JEREMY CATO

Globe and Mail Update

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July 19, 2007 at 11:01 AM EDT

Audi has published a conservative 4.8-second 0-100 km/h time for the RS 4 ($94,200), and I managed easily to break 5.0 seconds and I think I could do better if I tried harder.

This is why any sensible person would argue that the RS 4, the ultimate expression of Audi's A4 series, leaves BMW's M3 in the dust. The old M3, that is.

BMW has a new version of the M3 coming soon and it will spark a new series of head-to-head matchups — including this one with Audi. For now, we can say this about the 2008 M3: It will be powered by a V-8 engine based on the 5.0-litre V-10 found in the M5/M6 and horsepower will be north of 400.

The M3 needs this much power to compete with the Audi. Lurking under the RS 4's hood is a great 4.2-litre V-8 that started its life with the engine block from the S6. Then the pocket-protector types at Audi's Quattro division — think of Quattro as the equivalent of BMW's M group and Mercedes-Benz's AMG — went to work.

This is where the gearhead talk starts, by the way, and I'm digging into it because this stuff matters with a car like this. The built-in-Hungary V-8 in the RS 4 has ultra-high-compression 12.5:1 pistons, new connecting rods, a new crankshaft together with its bearings, new cylinder heads, a free-flow twin exhaust system and the FSI direct-fuel-injection system that was developed for Audi's Le Mans-winning race cars. Whew!

The result is peak horsepower of 420. It arrives, engine howling, somewhere just south of 8,250 rpm. Torque comes in at a somewhat modest 317 lb-ft. Yes, you need to work into the upper rpm bands to flog the best from this beast.

The RS 4 starts life on an A4 chassis and then all manner of changes come along to deliver enviable balance in a car weighing 1,795 kg. A fair chunk of that heft is the result of a heavily modified all-wheel-drive system.

This is not the A4's AWD system, either. The RS4's quattro system has a Torsen centre differential that ordinarily sends 60 per cent of the torque to the rear wheels and 40 per cent to the front. But if the wheels slip, up to 100 per cent of the torque can be sent to either axle at any time as needed. Moreover, there is a hypoid gear differential on both axles to distribute torque to the wheels.

The suspension system is the A4's basic front four-link and rear double-wishbone arrangement and more. The difference is an active ride system. It controls everything without any electronic intervention at all.

Pitch, yaw, dive and roll are all controlled in a brilliantly simple way. In a nutshell, each damper is hydraulically linked to its diagonally opposite counterpart and the movement of fluid is controlled by a central valve.

This arrangement is designed to stiffen or soften the shock absorbers to counteract roll, dive and pitch, while maintaining a compliant ride while cruising. And this system is backed up with a two-stage stability control system that even wipes the brake rotors for you in the wet.

Then we have the quick-ratio rack-and-pinion steering. Compared to the A4, it has been retuned for sportier driving and is excellent in every way.

The brakes? They are huge and racing-bred. In front, you'll find enormous ventilated and cross-drilled rotors teamed with eight-piston, high-performance calipers and four brake pads. At the rear, the rotors are similar, but with single piston stoppers.

Power is channelled through a gloriously smooth and precise six-speed gearbox. There is no automatic of any sort available and no sequential manual gearbox with paddle shifters, either. (By the way, you'll be past the legal speed limit by third gear.)

If all that sounds like too much, there is more. Hit the "S" button and the firm suspension turns to concrete. Hard-core types can also turn off the stability control, maximizing wheel spin and potentially scaring the bejesus out of passengers.

For all its hot-zoot engineering, the RS 4 looks pretty stealth. Audi says the A4 and RS 4 do not share sheet metal, but they certainly look similar.

The bulges around the fenders stand out and are there to accommodate the front and rear track that are wider in comparison with the A4. There is also a bolder grille, along with new bumpers, side skirts and a new trunk lid with an integrated spoiler. In addition, the RS 4 rides about 50 mm lower than the A4.

But that's it for obvious cosmetic differences. On the other hand, there are elements at work here that you cannot see. The front fenders, along with the hood, are made of aluminum to help with weight distribution (58 per cent of which still sits on the front axle).

Inside, it is a similar story of subtle change. Unlike in the A4, the RS 4 has carbon-fibre accent panels and super-snug Recaro leather seats. But the rest is all A4.

The RS 4 easily carves through curves with an intimate feel and razor-sharp responses. There is almost no roll from the car's trick suspension and cornering forces are simply ferocious.

As you might expect, pedal feel and brake performance are exceptional, shrugging off the RS 4's considerable heft. The communicative steering is perfectly weighted. We are talking about a staggering, balanced, poised driving tool. Not only that, in everyday driving, the RS 4 does not wear you out. On the contrary, it is a reasonably comfortable cruiser — fairly easy to drive hard for long periods of time.

Rivals? Aside from the M3, try these three, though there are others: the Cadillac CTS-V ($70,905), Mercedes-Benz E63 AMG ($119,800) and Dodge Charger SRT8 ($46,105).

The RS 4 is the only AWD car of the four and that immediately gives it a performance advantage. The other three are all rear drivers. For the record, the Charger has 425 hp, the AMG 507 hp and the Caddy precisely 400 hp.

The RS 4 and these others all follow the same basic formula: take a basic four-door sedan and modify it to improve power, grip, balance and braking. Presto! A four-door sports car. That's the RS 4, certainly, and the others, too.

In all this, the RS 4 stands out for the brute strength of its V-8 engine and smart suspension. If there is one big downside, it is fuel economy. At 16.8 litres/100 km city and 10.1 highway I'd call it brutal.

The howl of that V-8, though, just might bring you to forget or just plain ignore the pain at the pump.

[arcrox]

All that and a 335i competes/beats it at the track?

[RussianM3_dude]

Enviable balance????? What is he smoking???? 60/40 is a rubbish weight distribution. That's why there are very few magazines I trust in my reviews. Globe and Mail is not one of them.

[achien]

Originally Posted by RussianM3_dude

Enviable balance????? What is he smoking???? 60/40 is a rubbish weight distribution. That's why there are very few magazines I trust in my reviews. Globe and Mail is not one of them.

Obviously, their baseline is the awesome American 70/30.

As you are from Europe, you will never understand how anyone can rate good balance cars at anything less than 55/45.