RS4 (32 valve) S4 (40 valve) - WHY?

[mcster]

Why did the engineers use 32 valve heads in the RS4, as opposed to the 40 in the S4?

[ThirdStrike]

rs4 is fsi. different design... different flow

[mcster]

rs4 is fsi. different design... different flow

Can anyone offer further details? Or an article?

Thanks.

[a4dc89]

idk but 40 seems to be pushing it. the number of valves only make a marginal difference

[Todd/AWE]

Why did the engineers use 32 valve heads in the RS4, as opposed to the 40 in the S4?

There is just so much room in the cylinder head to fit valves, spark plug, and injector. From what I understand, on all the direct injection VWs and Audis, a valve was sacrificed in order to be able to efficiently fit the injector nozzle. The 2.0T engine is now a 4 valve instead of 5 valve design, too, and it is also direct injection.

[Silence]

FSI aka direct injection takes up the spot where the valve would be. 1 per cylinder = 8 less valves.

[Don Supreme]

FSI aka direct injection takes up the spot where the valve would be. 1 per cylinder = 8 less valves.

Bingo