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re: Bypass valve orientation?

>FWIW, nipple forward is the direction on the '91 200q.
>But you've stirred my curiosity about this cool "designer" bypass valve
>(and other variants). If the valve spring tension is different in various
>models, I suppose this must be to account for the varying levels of boost?
>If so, would "upgrading" the bypass valve be a useful thing to go along
>with ECU chipping? For example, would a chipped '91 200q benefit from using
>a stock S4 bypass valve--or some other? For that matter, is the stock S4's
>bypass valve significantly different (hose dimensions, etc) from the '91

According to many sources, the Bosch turbo bypass valve used in the 91 200
is a generic Bosch bypass valve, and a fairly old design; my father's '87
944T uses it.

However, many racing shops sell it, and on their web pages, next to huge
bypass valves with big chrome junk+everything, is the little innocent Bosch
valve, with a note, something along the lines of:
"This Bosch valve delivers the best performance of any valve in its size"(1
inch.)  The shops usually sell it for about $70.  Tried and true, I'm
leaving it in there :)


Brett Dikeman
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Te audire non possum.  Musa sapientum fixa est in aure.
Ita, scio hunc 'sig file' veterem fieri.