Sounds good when stretched out

GERMAN GRAFFITI: With an aural signature all of its own.
GERMAN GRAFFITI: With an aural signature all of its own.

I wish I'd taken my own advice and bought shares in Garrett, a turbocharger manufacturer, in the mid-noughties.

Back then, I suggested to NZ Autocar readers that there was a great opportunity beckoning as Garrett was forecasting that its production of turbos would double over the next five years.

It has since done that and a lot more, so anyone who bought into the company on my tip would have seen the value of those shares soar.

THE POWER AND THE GLORY: One of Germany's best V8s ever.
THE POWER AND THE GLORY: One of Germany's best V8s ever.

There's more to come with the potential for growth in the turbocharger business, as I suspect that it won't be long before just about every car utilises one to recover extra energy from spent exhaust gases.

The normally-aspirated holdouts will be cars like this Audi RS4 - cars that are targeted entirely at driving enthusiasts who have a penchant for high revs.

For there's just one thing wrong with fitting a turbo to a performance car to my mind - it automatically imposes a maximum of about 6500 crankshaft revolutions per minute.

Free of the tyranny of forced induction, the 4.2-litre V8 of the latest RS4 can go to 8500 revolutions per minute, and it sure sounds good when it's stretching out.

The 331 kilowatt, 430 Newton metre V8 is one of the older components of the RS4, having also done motivation duty for the previous model. When the latter appeared in 2003 there was only a single type of gearbox that could handle its talent for high revs - a good old shift-it-yourself manual. Despite being available only in three-pedal format, the previous RS4 sold well in New Zealand, with more than 150 Kiwi buyers stumping up the $169,000 required to secure one.

Five years later, the new RS4 is available as a wagon only, with a more convenient two-pedal driving interface, and costs $154,000.

As someone who thought the previous model was a great buy, that $15,000 price prune is eyebrow-raising, especially when you consider all the new hardware that the four-wheel-drive powertrain now sports, downstream of the engine, in the torque flow.

In comes a new seven-speed direct-shifting twin-clutch gearbox, a new crown-geared centre differential that is capable of greater adjustments in the amount of grunt distributed to either the front wheels or the rears, and a new rear diff that increases the torque distributed to the outside rear wheel when powering out of a corner.

The latter effectively pushes the car around the corner, snuffing out the power-on understeer that's usually a characteristic of a four- paw performance car.

With all this mechanical grip channelled into sticky Pirelli P Zero tyres of a suitable size and width, the stability control system of the RS4 is virtually made redundant on-road.

Take it to the track, however, and you might just find the one weak spot in what is an almost crash- proof chassis: if you get the corner entry speed wrong, the stability sentries will have some work to do correcting the understeer.

The RS4 is the performance car for all occasions thanks to the ability to tailor it according to the mood and application of the moment.

Four elements of the car - engine/gearbox, suspension, steering, and the rear differential - can be tuned to either comfort, automatic, or dynamic settings.

Audi's performance arm, Quattro GMBH, make only one RS model at a time, and they've now finished this run of RS4s, and are hard at work on a new turbocharged RS6. So if you'd like an RS that's capable of singing to the heavens, you'd best move quick.

Sunday Star Times