[s-cars] Bypass Valve Question

[Southerlin, Russell S]

I have this faint hissing sound that I suspect was a turbo leak.  It is almost a faint whistle but has that hissing sound to it. It is most notable when the boost first comes up.

I pressure tested the turbo plumbing by fabricating a plug at the engine inlet and another plug with a schrader valve at the crossover pipe. I found a hose clamp the was leaking slightly and only needed tightening.  Everything else held pressure for something like 10 minutes.  When you are under your car changing oil or doing normal service give those hose clamps a turn or two as a regular maintained item.

Next I  tested the Bypass valve by itself.  The PO said it was recently replaced and it does look fairly new.  When I apply pressure to the turbo outlet side of the bypass valve it opens (bypasses) with only the slightest of pressure (like 2-3 psi).  Shouldn't this thing stay closed for something like 20psi or more?  It just occurred to me that this thing may be installed backwards?  Should this thing be installed so that the turbo outlet pressure would force the valve closed and then the vacuum line would open it when throttle is closed?

Anyone have a picture or description on how the bypass valve is supposed to be installed?

Russell Southerlin
95.5 S6