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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by tj930 View Post
Thanks, Mark.

I've just taken a look at your thread and I can see that you've been busy! Obviously I'd be interested to hear what kind of benefit your modifications bring (even if it's as simple as, "Makes the car sound better under boost!").

But for now, if I put the thing back together correctly (with the new spring and O-rings I bought), I should be able to pretend like I'm 'playing the saxophone' or something and get the drum to move just a fraction?

Is the drum (on the right of the picture above) supposed to have a really tight fit in the barrel? Is all that grease I found in there supposed to help create an hermetic seal? My car's is anything but
That piston should slide freely inside the cylinder. Clean everything out well with a solvent, then lightly coat with oil. I've never heard of using grease inside to get a tighter fear would be that it slows the reaction time. There is probably an unavoidable miniscule amount of air leaking past between the cylinder walls and the piston, the only harm being that it may take a fraction of a second longer to build full boost. Therein lies one of the benefits of going with an updated recirculation valve.

As for playing the saxophone....I've never tried to move that piston with lung power alone. There's quite a bit of spring tension to overcome, which is why the vacuum source barb diameter is as large as it is.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 01-25-2010, 01:15 PM
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