My car builds boost to about 11psi @ 5000rpm and then flat lines from there as the rpms increase.

It -could- be best slip, but graphing the MAP from the F.A.S.T. it seems very flat, not jumpy like you'd see with belt slip.

Is there any way to tell if boost is leaking past my stock Vortech bypass valve?

 

best way would be to find a way to pressurize the system with air from a compressor.

 

Not sure how that could be done practically, unfortunately.

 

I was wondering the same thing, as I have the same problem.

I have a 6.00" crank pulley and a 2.95" supercharger pulley. I hit 11psi right around 5,000 RPM's, and maintain it up to 6,000. At 6,000 RPM's my impeller speed should be slightly over 42,000 RPM's. To put my S-trim just under its efficient max impeller speed of 45,000 RPM's, I upped my rev limiter to 6,400 RPM's, but I still show 11psi on the gauge .

 

I wonder if I could just stick a cork in it, literally. Would one or two runs without a bypass valve hurt things?

 

I've owned 4 turbo Mitsubishi Starion's. These didn't come with bypass valves. The only problem I would have was blowing up the intake hoses, but only if the waste gate actuator was disconnected .

I don't think it will hurt anything to run a few times with the bypass valve plugged.

 

Well, if you have to, remove the bypass from the car. Hook a hose of some sort up to it. Make sure the bypass is closed, and blow air into the the hose.... see what happens.