clack noise from the engine when I hit the gas
 

Hi got a clak noise when I rev the engine , like some valve is opening up.
is this normal?
Thanks

Sounds like the EXACT problem I am mentioning in my thread!
http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/486576-pop-off-valve-clanking-low-boost-high-rpm.html

99% certainty it's the silicon rubber gaskets on the end caps of the boost recirculation valve piston housing. They harden over time and don't cushion the piston as it returns to it's stop. Every time you step on the gas, or get off the gas, that piston will move in response to the vacuum (or lack thereof). You'll hear it when sitting still at idle, with a sudden tromp-and-release of the throttle.

Our host has the gaskets for a pittance, and it's just a couple hour job to replace them. Or, live with the noise. Only when the seals get so bad as to leak boost would you be forced to replace.

exactly the noise I have
where is this "boost recirculation valve piston housing."
Thanks

http://forums.pelicanparts.com/uploa...1248149566.jpg

any other parts I need to replace while I am removing it?what else should I do while there?
Thanks

Howto:

http://forums.pelicanparts.com/porsche-911-technical-forum/71370-changing-930-dump-gaskets-pictures-galore.html

great write up . once there is there a way to test the "gold disk"acell valve I think?
Thanks

Yep had same problem on a 89 930 i had!

I also had the same problem...not a clack....but more of a tick-tick as you tap the accelerator.tue rubber gaskets fix it just fine....relatively easy DIY. It doesnt' really hurt anything, just an annoying tick=tick.