7A Exhaust Cam

[90quattrocoupe]

I have another question about the 7A exhaust cam. Specs show that the exhaust valve is still open, overlap, when the intake starts to open on a S2.

I know this is good for NA motors, because it draws more mixture into the cylinder. But you also get a little unburnt fuel in the exhaust.

It seems like with a turbo, you would want the exhaust slammed shut, so you don't have fuel going out the exhaust.

What are the thoughts on this? Do you put an adjustable cam gear on the exhaust and retard it a couple of degrees to insure it is closed? You would shorten the duration a little, but you would still have the lift?

Thank you,
Greg

[Mihnea]

Re: 7A Exhaust Cam

Originally posted by desmo888
I have heard so much about the use of the 7A exhaust cam on the 3B and I wanted to get more info on this mod.

Are there dyno results showing increased power?

No, only assumptions based on facts such as increased timing and more lift. Should only be about 5-10 HP but the fact is that you can feel the difference in terms of breathability at high RPMs.

Have piston to valve clearances been checked?

Yes, no interference and still far from it.

[desmo888]

I have heard so much about the use of the 7A exhaust cam on the 3B and I wanted to get more info on this mod.

Are there dyno results showing increased power?

Have piston to valve clearances been checked?

Thanks!