02 Dec 05
The first disappointment was the specification of that mighty V10 engine. It's not a Lamborghini engine at all: correctly, the Lamborghini Gallardo is powered by an Audi engine and now it's back in its rightful home. And although Audi has expanded it from 5.0 to 5.2-litres for the S8, it has also reduced its power from an outrageous 520bhp to a rather less sensational 444bhp.
Second, although Audi bangs on relentlessly about its lightweight aluminium technology in general, and the A8's aluminium spaceframe and body in particular, it's only if you look in the small print that you realise that the S8 is, in fact, extremely heavy. Compared to the only other all aluminium rival, Jaguar's XJR, it's an immense 281kg heavier, or more than four 12 stone blokes.
Why does this matter? Because whether you're talking performance, handling, economy or emissions, the heavier you make your car the worse it will perform in every last one of these areas. Which is why the XJR can afford to produce 50 less horsepower than the S8's and still enjoy a considerably better power to weight ratio which is the vital determinant of performance.
Ah, says Audi, our S8 will hit 62mph in 5.1sec while the XJR needs 5.3sec. Yes, says me, but only because the S8 has four-wheel-drive and therefore greater traction in such artificial tests. Out there in the real world, the XJR should always be quicker.
