Blow Off Valve Woes - R32 Gtst

[blacky]

Hey guys,

Well i'm onto my next drama with my new skyline, we installed a new Revspeed atmo BOV onto the car but I just cannot get it to function correctly. Heres the setup.

1. 5c piece size hole cut into cooler pipe to manifold.

2. about an inch of 1 inch pipe welded around the hole

3. small section of 90 degree radiator hose clamped over pipe, other end clamped onto BOV (the port that pushes on the piston)

4. vacuum source at manifold - we used the source between the throttle body and AAC valve on the passenger side of the manifold (theres two hoses, its the upper one)

5. 4cm of vacuum pipe from there to metal tubing that follows cooler piping down to the BOV.

6. hose clamped to metal piping then run to vacuum nipple on BOV (the line is quite thick, like fuel hose thickness 1/4 in)

I know its not the best setup (ie. no welding) but now the problem is that no matter how much boost I run, the valve just wont open - instead i get the same compressor surge that I did before the BOV was installed. Its like there isnt enough vacuum to pull the piston off its seat or the hole we cut into the cooler pipe is too small, thus not allowing enough air to push the piston open.

Can anyone shed some light on where i might have gone wrong?

The car is an r32 gtst with an HKS turbo, runnning either 0.5 or 1 bar of boost.

thanks in advance!

Blacky.