Do I need a large compressor to test for a boost leak?
 

I am currently using a small 12v compressor and inputting air at the turbo intake-I isolated from turbo inlet to throttle body and that held at least 20psi from my small compressor. Now I have the system hooked up as normal (just that i'm pumping air into the turbo inlet) and it won't build up any pressure...before I was detecting a leak at the injector heat insulators and replaced those-they make no noise now...is there somewhere else the air could be escaping not allowing it to build up pressure-OR do I need to pump WAY more air into the system to find leaks? Thanks!

Did you plug up your exhaust? Unless I am having a 'stupid' moment, lol, all the air you are pumping in will just go out the exhaust.

--Ferdi

hmm, you might have a point there-but I've been reading on other boards (just turbo boards) none of them mentioned plugging the exhaust when they tested-so I dont know.

You don't plug the exhaust. You need to pump 8-10 psi to hear the leak so even your 12v compressor should be fine. If it's enough to pump up car tires, it should be able to pressurize the system to find a leak.

Frank

have you tried rotating the motor. I remember one time with my old boosted car, that the motor had stop just at the point that both the intake and exhaust valve were open on one cylinder.

I just use a bicycle pump I dedicated for the job. Cut off the end and just put the hose on the barb.

god you're clever.

where do you pump in the air? Doesn't it leak through the turbo out the intake unless you pump it directly into the turbo air inlet?

You obviously haven't googled the Home Depot/Lowes boost leak tester. I'm not going to spoon feed it to you either.

i've googled probably 10 boost leak tester pages...looks like I need to get a compressor with tank to do it properly-that's what a lot of the pages tell me. I think a small pump will only work if there are zero leaks from what I've read. nevermind, i'll figure it out.

You pump the air straight into the turbo inlet. There's no point doing it at a point before that as tubing prior to that is not subject to >atmospheric pressure. Plus, a 'leak' pre-turbo wouldn't matter if you have removed the AFM... actually you wouldn't even call that a leak. Stop going mad trying to find an uber strong compressor - my bicycle pump can push 100 psi into a road cycling tire and can inflate my race tires... ANY compressor is more than enough.
-Ryan