Thread: no boost?
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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 5050racing View Post
Didn't dislodge the rag,not jammed in to tight but snug quick rev to 5000 or so .Any other ideas?It runs fine smooth,I drove it just not a lot of power?
The boost recirculation valve internal piston may be stuck open. It should only open in response to engine vacuum when you're suddenly off the throttle (during shifts and/or at idle). It should close once the throttle is opened and allow boost to build as opposed to recirculating back to the front of the turbo. It's a simple spring loaded piston within the housing situated left and back of the intercooler. Has a big 1/2" vacuum hose connection on one end that drops down to the intake manifold. Take it apart, clean and inspect.

You could also pull the turbo compressor intake hose off the turbo and visually inspect the compressor wheel for damage, and check to see that it spins freely.

If all that checks out, then something else is causing the engine to run with less power, not generating sufficient exhaust gas pressure to spin the turbo enough.
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 09-22-2010, 02:41 PM
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