boost leak test

[MikeLary]

okay fellas ive built a boost leak tester, simply:

1) $20 ciggie lighter compressor off ebay
2) $2 tyre Valve
3) a plastic T

What ive done is T off just after the boost gauge and connected the tyre valve to that (keeping it inside the car as the bloody thing is noisy so i can close the doors on it)

now to start seing if this works i connected compressor to tyre Valve and to the ciggie lighter.

I wanted to start by building pressure in a single hose so i blocked off the other end of the hose thats connected to the compressor and the end thats supposed to connect to brake booster (preventing air from going in brake booster)

that builds 15 psi instantly just fine...

then i unblocked that hose and connected it straight into the TB (disconnecting brake booster), so bascially compressor blows air straight into the TB (batterfly shut to limit testing space) but now i can't build pressure,

any idea why that is?

[Spicey]

I dont get exactly what ur on about but could it be air leaking past the TB, through your inlet manifold, past an open inlet valve and through an exhaust port!?

[MikeLary]

ah okay so doing a boost leak test on the tb is a pretty useless idea

[Spicey]

Yeah, TB aren't airtight. If they were your car would stall when off the throttle.

[MikeLary]

okay i figured its because one of the valves must be open, so im not testing past the batterfly anymore, just gonna test pipes.