question about boost leak.

[forcedfed69]

alright i think i have a boost leak but my guage reads fine. it says its holding at 18lbs steady. question is can i still have a boost leak if my guage reads fine? Thanks for the help guys.

 

[super97gst]

You're boost guage is not going to give you any information about a boost leak. If you had a boost leak bad enough to affect the reading on your boost gauge you would definitely know it. An intercooler pipe would have to be completely blown off for that. The only way you're going to know where and how bad your boost leak is will be to do a boost leak test. Test your system up to 20-30 psi. It will work best if you can hold the pressure at about 20 psi, like with a portable air tank. Once you have it held at 20 psi count how many seconds it takes for each single psi to leak down. You can also use a spray bottle filled with soapy water to spray over the intercooler piping and throttle body/intake manifold to see the leaks better.

 

[1gDSM4g63]

Yup, super97gst is correct. The boost leak tester won't tell you anything if it's a minor leak. You have to find the leak yourself while you're pump air or hear the leak when you're not.

 

[forcedfed69]

hey guys thanks for the info. yeah i'm going to do the boost leak test. it just suck cause the stock turbo ran a 14.1 at 94 at 17 lbs. i installed a big 16 g ported and clipped running 18 lbs ran a 15.1 at 85 the plumbing is pretty rough but it seemed like it ran alot faster when i first installed it and now feels reel slow a year later. just don't know where to start. its a used turbo but it didn't seem like it had any shaft play. but there is oil around the turbo and in the intercooler piping. don't know if thats usual? and would a boost leak not noticible on my guage make that much of a difference in power?

 

[super97gst]

hey guys thanks for the info. yeah i'm going to do the boost leak test. it just suck cause the stock turbo ran a 14.1 at 94 at 17 lbs. i installed a big 16 g ported and clipped running 18 lbs ran a 15.1 at 85 the plumbing is pretty rough but it seemed like it ran alot faster when i first installed it and now feels reel slow a year later. just don't know where to start. its a used turbo but it didn't seem like it had any shaft play. but there is oil around the turbo and in the intercooler piping. don't know if thats usual? and would a boost leak not noticible on my guage make that much of a difference in power?

Pull your intake pipe off and check for shaft play on the turbo. That will tell you what kind of shape your 16G is in. And yes, a boost leak can make such a difference in power it'll feel like a dog. Just get your bottle of soapy water and boost leak tester and get to it.. Then you'll know where you stand. Also, is the oil in your lower intercooler pipe?? If so, a small amount of it could be coming from your 16G, but most of it is probably coming from the breather hose connected to the pcv valve on the valve cover. You might consider cleaning out your intercooler with gas after you do this other stuff.

 

[forcedfed69]

Hey guys. Thanks for all the help. I'm going to get started on it today. But i think i'm just going to get all new blumbing for her to start.

 

[MPDano]

You're boost guage is not going to give you any information about a boost leak. If you had a boost leak bad enough to affect the reading on your boost gauge you would definitely know it. An intercooler pipe would have to be completely blown off for that. The only way you're going to know where and how bad your boost leak is will be to do a boost leak test. Test your system up to 20-30 psi. It will work best if you can hold the pressure at about 20 psi, like with a portable air tank. Once you have it held at 20 psi count how many seconds it takes for each single psi to leak down. You can also use a spray bottle filled with soapy water to spray over the intercooler piping and throttle body/intake manifold to see the leaks better.

I have a compressor with a guage on it, where would I hook this up to do the test? My 98 GST may have the same symptoms. Really lags on power. Seems a lot louder than it used to be (can really hear the intake or turbo - not sure which). I also step on it and it sputters like it's starving and you hear pops, then it grabs and takes off. Does mine sound like a leak?

 

[MPDano]

Anyone got any suggestions?