A late-stage prototype Audi RS5, fitted with a very potent ‘e-boost’ version of the next-generation Audi 3.0-litre V6 two-stage turbodiesel engine.
The new engine weighs 192kg, somewhat lighter than the previous version, and will arrive first this summer in the newly facelifted A6 and A7 in 215bhp and 268bhp forms. This 380bhp prototype, however, is expected to go into production next year, possibly as the first-ever Audi RS diesel.
Like many of today’s higher-end diesel engines, the new unit uses two-stage turbocharging. The smaller of the two is lighter and easier to spin up, and is intended to give the engine more grunt at lower engine speeds. The bigger turbo takes over at higher speeds.
The engine we’ve driven here is, however, something of a landmark design in that it uses electrical assistance to ensure that the smaller of the two turbochargers is spinning quickly enough to be active even at very low engine speeds.
We drove the car at Audi’s new short driver training circuit near Munich. While this was a long way from the open road, the track’s very tight curves, which demand a great deal of braking and re-acceleration, were ideal for testing out the ‘e-boost’ promise.
You can’t – yet. While the Audi engineers on hand during our test were tight-lipped, I’d expect this engine to be offered some time next year.
It is also likely to appear in RS form thanks to the fact that the ‘diesel-ness’ of this unit has been almost entirely eliminated, thanks to a combination of e-boosting, its pretty free-revving nature and the artificial sound generation of the exhaust system.
The question that hasn’t yet been answered is why RS customers – who presumably are not too sensitive to petrol prices – would want to buy a diesel-powered car. The Audi engineers I spoke to are still very bullish on the future of diesel and suggest that oil-burning is still the supreme motive power for long distance, high-speed, motorway journeys and cross-continental drives.
Moreover, after winning Le Mans with diesel powered sports cars, Audi finally has a diesel engine good enough to put in a future R8.
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