Audi S5 - RS4 lumps - Differences?

[steve--m]

Can anybody highlight the main differences between the two 4.2 V8's found in the cars in the title please?

I'm guessing cams and mapping for a start but what else would be required to bring the S5's output closer to that of the RS4's?

Cheers

[plg101]

steve--m said:

Can anybody highlight the main differences between the two 4.2 V8's found in the cars in the title please?

I'm guessing cams and mapping for a start but what else would be required to bring the S5's output closer to that of the RS4's?

Cheers

I think the S5 lump is closer to the S4 lump...

[Andyuk911]

Well I thought the S5 was NOT FSI ...

But

Engine
Delivering 354bhp, the V8 FSI® engine gives the new Audi S5 a high degree of spontaneity and responsiveness alongside its sporty and emotive driving experience.

One look at its muscular body styling, 19” alloy wheels and subtle V8 badging, and it’ll come as no surprise that the Audi S5
features a powerful 4.2-litre V8 engine, capable of taking you from 0 to 62mph in under 6 seconds. And from the comfort and
stability of a stylish Silk Nappa leather Sports seat, you can sit back and enjoy every single unit of this engine’s 354PS capability,
safe in the knowledge that the quattro®permanent all-wheel-drive system will keep you exactly where you want to be – on
the road.
But sleek styling and powerful performance in the S5 don’t come at the expense of functional, driver-oriented specifications.
Simple yet thoughtful touches, such as the matt-brushed aluminium inlays, S instrument dials and through-load facility have
been included to ensure that your life runs as smoothly as your Audi does.


I know the intake manifold is different and the RS4 revs to 8250 rpm. The RS4 has a very complex flaps in the intake and a flapper in the airbox that opens depending on speed and gear. Also the RS4 has two ECUs .. master and slave .. don't know about the S5.







HTH

[steve--m]

Thanks Andy, yes the intake manifolds would make a difference. I'm surprised the S5 isn't FSI though as it sits in a "later" car, wonder what the Audi rationale behind that was?

[sleepersix]

S5 is FSI isn't it? I thought it was an FSI version of the S4 motor?

[Andyuk911]

For the avoidance of doubt, the S5 IS FSI .... it was me who thought it was not.

[Tame Technician]

Some where on here there is a detailed thread on the difference between S4 and RS4. S5 is just an S4 engine, but with FSI. Worth a search, if I find it I'll add it up here.

There are dramatically different, you will never raise the S5 engine to RS4 spec, would cost more than the car.