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Audible boost leak...but where?


holeshotmoe
subclass marmoreus


Galant VR-4 org Post #: 931148 posted 09/14/10 05:18 PM     Remind Me!  Send Private Message   Edit Post      
Moderately accelerating in 2nd or 3rd and I can hear air, ssshhhhhh, increasing louder and louder as boost climbs. The sound starts at about 7-8 psi and is preventing me from boosting above 15 psi or so. Checked the entire circuit except right at the turbo outlet, the bov, and the intake manifold. What's the most likely culprit? And are there procedures for testing the bov? Can I charge the manifold with the valves at TDC to hear leaks at the head seal? Have hard IC pipes, and a stock bov and manifold. Thanks.



Done there, been that


Edited by holeshotmoe (09/14/10 05:21 PM)

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mitsuturbo
Banthony
555/1000


Galant VR-4 org Post #: 931157 posted 09/14/10 05:27 PM     Remind Me!  Send Private Message   Edit Post      
Stock intercooler and intake manifold?



92 GVR4 555/1000 11.41 @ 128.26mph
97 CBR900RR
2012 Hyundai Veloster

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holeshotmoe
subclass marmoreus


Galant VR-4 org Post #: 931166 posted 09/14/10 05:40 PM     Remind Me!  Send Private Message   Edit Post      
Intake manifold is stock. IC and steel pipes are custom. Whatever it is, it began after I started cranking boost above 1 bar, almost as if it blew a gasket. Just wondering if it's more common at the manifold, the outlet at the turbo, or if the stock bov is known to leak. My bov is recirculated by the way, so I don't think it's that because it's really loud. Also, just before shifting when under load, the engine starts to break down (misfires), which I believe is because the AFR is screwed up from the leak (and another reason I don't think it's the bov).



Done there, been that


Edited by holeshotmoe (09/14/10 05:41 PM)

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mitsuturbo
Banthony
555/1000


Galant VR-4 org Post #: 931168 posted 09/14/10 05:52 PM     Remind Me!  Send Private Message   Edit Post      
you could have blown at a coupler, although i assume you triple checked both sides of each one
you could have blown a seam/weld on the intercooler. unfortunately i've seen this happen on a couple



92 GVR4 555/1000 11.41 @ 128.26mph
97 CBR900RR
2012 Hyundai Veloster

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cheekychimp Galant VR4.org Moderator
Director of Housing and Urban Development, and carbon/kevlar balls


Galant VR-4 org Post #: 931238 posted 09/14/10 08:52 PM     Remind Me!  Send Private Message   Edit Post      
Although I don't know if you can technically call it a 'boost leak' being pre-turbo, have you looked at the exhaust manifold? One other little problem I need to address on my car is a broken manifold stud/bolt. You can hear air escaping there.



Getting old sucks ... but it sure beats the alternative !!!

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mitsuturbo
Banthony
555/1000


Galant VR-4 org Post #: 931296 posted 09/14/10 11:08 PM     Remind Me!  Send Private Message   Edit Post      
the one by the PS pump is always giving me problems, although i've never heard it "hiss" under power



92 GVR4 555/1000 11.41 @ 128.26mph
97 CBR900RR
2012 Hyundai Veloster

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cheekychimp Galant VR4.org Moderator
Director of Housing and Urban Development, and carbon/kevlar balls


Galant VR-4 org Post #: 931316 posted 09/14/10 11:58 PM     Remind Me!  Send Private Message   Edit Post      
^ Yeah, that's a good point, I doubt you would hear that from the cabin. You can probably disregard that idea



Getting old sucks ... but it sure beats the alternative !!!

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RedTwo
Rangi Kiwi


Galant VR-4 org Post #: 931359 posted 09/15/10 03:56 AM     Remind Me!  Send Private Message   Edit Post      
Just to discount the obvious - have you recently removed the housing/can that covers the factory air filter and AFM?

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vtecds1
linkfail
625/2000


Galant VR-4 org Post #: 931376 posted 09/15/10 07:54 AM     Remind Me!  Send Private Message   Edit Post      
All I can say is take your time in finding the leak. It took me 2 weeks to sort out my problem. Here`s where I found my leaks...couplers, barbed hose fitting on turbo, ex-mani had 5 cracks on the welds, bov flange had a crack on the weld, t-body shaft seal was bad, AFPR vacuum line, wastegate hose and boost controller hoses.



Avoiding danger is not cowardice. Courage without discretion is no good. Or you can just say Bahala!!!


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RalliArtGVR4
Unregistered


Galant VR-4 org Post #: 931445 posted 09/15/10 11:08 AM     Remind Me!  Send Private Message   Edit Post      
get a toilet bowl coupleing from homedepot and a pvc end cap hose clamp them together drill a 1/8 inch hole for a air compressor fitting and tap it into the top. then set your air compressor at the desired boost you want ( using a hvlp pressure regulater helps) then put the coupler snuggly on the air inlet of the turbo snail and put your air hose on. do not go higher then the boost you will be running at. thats the way i also checked for leaks works great. you will hear the hissing noise and possibly feal air out of whereever you are leaking from. hope this helps

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holeshotmoe
subclass marmoreus


Galant VR-4 org Post #: 1118315 posted 04/14/13 11:53 PM     Remind Me!  Send Private Message   Edit Post      
Found this old post of mine and realized I hadn't followed up. It turned out to be a seam weld in the IC. Big fat tanks made of thin-walled aluminum resulted in them flexing as pressure increased. After a while they drew a crack. Rewelded and it blew in another place. Had someone weld it right and its working fine now.



Done there, been that

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EROCK970
Junior Member
970/2000


Galant VR-4 org Post #: 1118484 posted 04/16/13 12:10 AM     Remind Me!  Send Private Message   Edit Post      
Get ur self a boost leak test. They are great thing to have

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James
Does lots of head


Galant VR-4 org Post #: 1118499 posted 04/16/13 04:45 AM     Remind Me!  Send Private Message   Edit Post      
I thought maybe you were just hearing your turbo spooling



1990 Summit White Galant GSX
Chipped EPROM ECU/2g maf/550cc injectors/3in exhaust /E316G/FMIC/Wally255/AeromotiveAFPR/lower shores MBC

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holeshotmoe
subclass marmoreus


Galant VR-4 org Post #: 1118627 posted 04/16/13 10:22 PM     Remind Me!  Send Private Message   Edit Post   
Quoting EROCK970:

Get ur self a boost leak test. They are great thing to have



That's what I used to find the leak



Done there, been that

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