UPDATED! Audi will unveil its hot S4 saloon in autumn 2008 - and it's losing the V8 engine of old in favour of a new supercharged V6 petrol engine producing around 350bhp.
Powering Audi's latest hot-shot saloon is a new-generation 3.0-litre supercharged V6, which will send its power to all four wheels through Audi's Quattro drivetrain. The supercharger is a Rootes blower that is said to be especially compact; the supercharger and the intercooler sit within the 'vee' and engineers claim the engine takes up no more space than a naturally aspirated 3.0-litre V6, CAR Online can reveal.
They are also proud of the layout, as the supercharger's positioning cuts down the journey air has to take from the compressor to the cylinders – speeding up throttle response. Top speed will again be limited to 155mph while the 0-60mph sprint is forecast to be around five seconds.
Why drop the V8?
Noticed fuel prices recently? It's pretty obvious really: a downsized, blown V6 provides significant improvements in emissions and economy, while also weighing less and being easier to package. Plus the engineers have retained the torquey feel of the old V8, thanks to the compressor's low-down shove, peaking at 406lb ft (the transmission's maximum torque rating).
The S4 will share the S5's new S-tronic seven-speed twin-clutch transmission and its lightning-fast 200ms gearchanges. The S-tronic gearbox weighs 142kg - around 40 kilos more than Audi's six-speed manual. However, performance is actually faster with the twin-clutch 'box and emissions are lower, as the transmission changes up earlier when in Drive mode.
Expect to see the new S4 at the Paris motor show this autumn before UK sales kick off in spring 2009. Saloon, Avant estate and convertible bodystyles will again be offered, with styling inspiration taken from the S-line A4 models (pictured).
Enough about the S4. When will we see the RS4?
The RS4 won't be seen before 2009. Michael Schoffmann, Audi's transmission boss, told CAR Online: 'With RS models we can make the gearchanges on S tronic even faster; regular models take 200ms, but on RS models we can trim that to 140-150ms.
'You'll have to wait until 2009 to see something, though!'
Other engineering sources suggest that the RS4 will drop the excellent, high-revving V8 for an even more highly tuned version of the supercharged V6 running higher boost pressure.
Is turbocharged V6 power the right move for Audi, or would you prefer a big V8? Click 'Add your comment' below and have your say.