Thread: BOV orientation
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mark houghton mark houghton is offline
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Location: Central Washington State
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Originally Posted by billjam View Post

As far as vaccum readings are concerned, the red line is what I usually see at light throttle cruise and the green line is throttle closed on over-run.
Thanks Bill. Your gauge looks like 23.6 inches of vacuum when the throttle plate is closed, and about 7.9 inches at cruise. Where is your boost line connected...directly beneath the throttle body plate or further downstream in the intake manifold?

Assuming I will see similar vacuum at cruise, then I would want to calibrate my spring tension to an equal and opposite force, which would be 3.88 Psi to counteract the vacuum and keep the piston closed. Pretty light spring tension, yes.
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 12-08-2009, 10:19 AM
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