Most people, even those without an interest in cars, associate Audi with quattro 4WD. It's the point of difference from its German competitors, but it has also been a mixed blessing.
The extra grip comes at the expense of added weight, much of it front-biased, and understeer is therefore the predominant handling characteristic.
That hasn't stopped Audi from producing some spectacular quattro-enhanced offerings.
Back in 1994, the company pioneered the concept of the stealthy supercar-baiting Q-car long before any concept of its Q crossover vehicles even existed. The first Renn Sport vehicle, the RS2, was a hyper-estate with a turbocharged in-line five-cylinder engine and quattro driveline. It was the forerunner to the most recent second-gen RS4, available in sedan, cabriolet and wagon versions.
For the third-generation, the RS4 reverts to type with an Avant-only body shape. For those wanting something with wilder styling and fewer doors, there's the RS5. Mention of which, RS4 Gen III takes the RS5's engine, an even more powerful version of the 4.2-litre direct-injection V8 that debuted in the 2006 RS4.
In what is probably no great shock to RS lovers, though is sure to upset the purists, the six-speed manual transmission that was a feature of all previous variants has been abandoned, and the power of the high-revving V8 is now processed by a seven-speed twin-clutch transmission.
With taller overall gearing, mean fuel economy is a claimed 10.7L/100km, an improvement of 26 per cent on its predecessor.
Despite an increase in body size and kerb weight (around 75kg), the latest RS is even quicker, racing through to the 100kmh mark in a quoted 4.7s (previously 4.9s). A launch control system ensures the RS explodes off the mark, and the S-tronic transmission blazes through upshifts faster than any human can stick-shift manually. The rest is down to the extra 22kW of power output (331 in all), delivered at a sonorously stirring 8250rpm, while the peak torque figure remains at 430Nm, arriving between 4000 and 6000rpm.
The launch of the vehicle took place at the Red Bull circuit in Zeltweg, Austria - which underlines Audi's confidence in the dynamics of the new car, especially given its predecessor wasn't a particularly happy camper in such environs.
The big technology update for the third-generation RS4 is the adoption of the crown-gear centre diff and torque vectoring, standard fit, and also the option of a rear sports differential. All the track evaluation cars had this, along with sports suspension and Dynamic Ride Control (variable damping).
What a transformation, particularly as the 60/40 axle loadings are little different from before.
Here is a vehicle with permanent 4WD and a wagon, no less, that makes like a rear-drive sports car, except with gobs more grip. Why, it even has an intermediate ESP setting, which prevents engine nobbling when the rear tyres are unstuck by a weight transfer and sudden application of throttle.
Spectacular but safe drifts when accelerating are now on offer, says Audi.
Overlaying this marked change in track demeanour is a sense of mechanical grip and security that has been the hallmark of RS 4s of the past, only more so now with the extra apportioning of rubber - 265/35R19s are standard - and the additional body control that's afforded by active damping, especially on the firmest (Dynamic) setting.
Dynamic indeed. This is as much of an upskilling as we witnessed in the latest generation 911. No surprise really, as both benefit from active torque vectoring at the rear.
Think of this as Audi's counter to BMW's Integral Active four-wheel steering system; it has a similar effect, the rear wheels helping the fronts to turn the car but instead of actually changing rear-wheel angles, the power of the inner unweighted rear wheel is diverted to its fully laden counterpart, the extra drive helping to turn the car in the direction the steering wheels are pointing.
Simultaneously, passive torque vectoring on all four wheels is helping to achieve the same outcome, by individual wheel braking. Tricky tech, this, but effective.
It's so not like the RS4 of old, though it does sound every bit as exotic.
The extra stick and the added agility thanks to torque vectoring produced laugh-out-loud moments of disbelief on track. We had to seriously bend this thing into a downhill off-camber corner and then jump on the gas mid-turn even just to activate the ESP. Any incipient understeer moments can be caressed back to neutrality by adding throttle, or removing it.
Audi is committed to constant improvement of its trademark quattro 4WD system; and while it may have taken 30 years, we believe now they may have finally nailed it. The new RS4 arrives early in 2013, when more details will be made available.
- © Fairfax NZ News
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