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Old 11-07-2020, 07:43 PM   #1
valerka6234
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Member#: 349565
Join Date: Mar 2013
Default Power Loss / Boost Leak? / Up Pipe? / Loud Squealing

Hey guys. I have a 2014 Sti that is basically stock.

Iím having a loud squealing and hissing noise whenever my car goes to boost (3k rpms). Sounds like a loud pig! Noise sounds like is coming from passenger side. I checked for boost and vacuum leaks and replaced the following:

Intercooler couplers
Turbo inlet hose
All clamps

Car acts normal when idling; only weird under boost. Any idea whatís going on?
Could an up pipe be causing problems?


Problems started after I test fitted a cold air intake, took it for a drive, and put the stock back on (I know, it needed a tune).
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Old 11-08-2020, 12:02 AM   #2
Raven2510
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Chapter/Region: MWSOC
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2012 WRX Sedan
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Did you check the intercooler to throttle body coupler? Its know to slide off or crack.
Check the turbo inlet where it meets the turbo. It can also crack or fall off.
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Old 11-08-2020, 12:17 AM   #3
valerka6234
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Yes I changed them both
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Old 11-08-2020, 11:22 AM   #4
heiche
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sounds like a boost leak test might be in order. it only takes 2 or 3 psi usually to find leaks. checking by eye is a good first thing to try, but there are so many places that boost leaks can hide - but they usually can't hide from a boost leak test. while testing listen for the same noise, sometimes you can feel air blowing out from a leak, or sometimes spraying soapy water on everything will cause bubbles at the leak.
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Old 11-08-2020, 12:41 PM   #5
valerka6234
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Do I need to block off the vacuum lines and open the engine oil cap before I do a smoke test? Iím getting different answers from different people
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Old 11-08-2020, 12:48 PM   #6
heiche
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yeah, lots of different ways to do it. personally i just go for the very low (2 or 3 psi) test, remove oil cap, then remove the large hose from the air cleaner housing and use something cobbled together to get air into that. then listen and feel for leaks, and spray soapy water if necessary on everything that could be a leak.

with that low pressure test, i don't find it necessary to block off any vac lines etc.
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Old 11-13-2020, 03:18 AM   #7
Sjp831
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Location: Santa Cruz, CA
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Quote:
Originally Posted by heiche View Post
yeah, lots of different ways to do it. personally i just go for the very low (2 or 3 psi) test, remove oil cap, then remove the large hose from the air cleaner housing and use something cobbled together to get air into that. then listen and feel for leaks, and spray soapy water if necessary on everything that could be a leak.

with that low pressure test, i don't find it necessary to block off any vac lines etc.
if you do a smoke test, is that more thorough then a pressure test? or do they achieve different things?
also when doing a smoke tes, do you need to block off vacuum lines?? i need to know as well lol
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Old 11-20-2020, 12:23 AM   #8
AliBenn
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Lots of people would say this harms rubber hoses etc
But
I would spray either carb/brake cleaner around engine bay
With car idling.......if you have dip/rise in RPM.....there is your leak man

(If u use non-chlorinated BC, RPM will dip down)
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