How do you know if you have a boost leak?

[toutsuu]

What are the possible symptoms of boost leak? Can you tell you may have boost leak without actually doing a test and finding out for sure?

My car hits 12psi then slowly drops down to 9 as I work from 4000rpm to 7000rpm... is this normal, or is this what you call boost creep?

Sorry for the newbie questions

 

[xveganxcowboyx]

Youi won't know until you do a test, but 9psi is normal for a 1G. 12 is a bit of a spike actually.

Boost creap is when the boost continues to rise, not fall.

If you have access to a compressor you might as well do the test. It's cheap and easy, two rare things with cars.

 

[toutsuu]

Well it holds 12psi for a while, and only starts to drop as the RPMs reach 6000. I thought this might be normal. Should it stay the same boost the whole time? Is boost spiking a bad thing? Creep is obviously bad because you are not hitting your max boost when you should be right?

I remember someone saying that spike is when your turbo hits max boost and then settles on something more normal for the RPM... so isn't it normall to be at higher boost around 4000RPM than at 7000RPM when the car loses power.

Keep in mind that I have most of the free mods done to my car which includes taking out the restricter on the stock boost controller.

I've also noticed that I will get a higher boost reading when the car is cold/not been running for a while. Could the decrease in boost be due to heat soaking the intercooler or just lower performance in general when the engine is hot?

 

[toutsuu]

Thought I'd bump this because I'm really curious about it and no one answered

 

[AWDMENACE]

I don't want to be an asshole but i do baleave that if you looked in the newbie forum you would find more then a tremendous amount of info on the symptoms of boost leak, but since I'm replying to your post the most common sing of boost leak would be as your accelerating if your turbo kicks up then drops and studders as you accelerate.Also as stated before the test is extremely easy and affordable. Good luck

 

[oldman]

Boost leak test. There is your answer, it's for finding boost leaks, hence the word TEST.

 

[toutsuu]

Well I don't really have those symptoms so I was wondering more about what boost the should be at at certain RPMs. I kind of shifted my question in my second post to "Should the boost be dropping between 6000 and 7000RPM?"

Is this a system of heat soaking... like when you don't run as fast when you just drove 60 miles on the highway... I know that if I make a run at Bandi as soon as I get there I can only pull a 15.9, but if I let the car sit for at least the recommended 30 minutes I can get a 15.4

I considered making a new thread titled: "should boost drop at 7000RPM" or something but decided it was better to post in the thread I already had going as is said to do in the rules. I'm sorry if you didn't catch that I was asking a different question now.

 

[oldman]

what have you got to lose? Do the test already. You have a 91' that probably have never been tested for leaks since it left the factory, your chance of a leak free intake tract is next to none. Prove me wrong and I will give you a rep point.

 

[jaredgsx]

what have you got to lose? Do the test already. You have a 91' that probably have never been tested for leaks since it left the factory, your chance of a leak free intake tract is next to none. Prove me wrong and I will give you a rep point.

yeah a 14 year old car that does not have a boost leak that needs to be fixed would be a tad rare. Trust oldman, he knows what he is talking about. The boost leak tester cost me about 4 bucks to make and its one of the easiest things to test. With a car you always want to know not assume.

 

[xveganxcowboyx]

Dropping a little bit is normal. Alot of turbos spike some and settle.

Boost spike doesn't necessarily mean it spiking to max boost, just going above set levels. It can spike a little or a lot. No big deal. Boost creep can be a bigger deal...

Heat soaking won't do much to effect peak boost levels. It will result in knock and pulled timing, thus a slower time.

Hope your questions are answered.


BTW, bumping is a bit of a no-no around here. I feel bad though, because I was going to answer riht away, but I thought someone more knowledgeable would come along.