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1G BoV sound changing

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sinned4g63

Proven Member
320
86
May 1, 2017
Pasadena, Maryland
I feel like this is a really silly question but here goes.. Since having done the repairs on my car and replacing the UICP, intercooler itself, and filter I've notice my blowoff valve sound changes from time to time. I've checked all the connections and made sure everything was tight, felt around the intake tube (short of removing it) to check for cracks/tears/holes/leaks, tugged around on the couplers and clamps, thought maybe the recirc tube was damaged but no.. boost builds perfectly fine through and through, car runs and idles just fine. Just concerning that a set unadjustable BoV can change noise as if it were being adjusted.

The noise it usually a nice short high pitched whistle which is seemingly more noticeable with the cone filter, but of late has been changing randomly to more of a less restricted sound if that makes sense. Like as if it were vented or set too loose, it tends to sound more like someone blowing through a straw. I can try and make videos but that depends on what it currently sounds like.

I first noticed it on Friday last week during it's first long ride, about an hour or two in changed from the norm. This morning on my way to work was like that for the entirety of the 20 minutes drive when it had been sitting all night. I had read on checking the turbo which when I fitted the Injen intake felt fine but I did not use any pliers to move it, just by hand. I could not feel any play either in and out or side to side. Any thoughts would be appreciated, thanks.
 
Compressor outlet gasket? Mine blew out recently and changed the bov sound as it wasn't having to release pressure. My gasket was acting like a Reed valve.

Though if you're MAF is still in the stock position it should be having some kind of issue I'd think.

edited for spelling/autocorrect errors.
 
Last edited:
Compressor outlet gasket? Mine blew out recently and changed the bov sound as it wasn't having to release pressure. My gasket was acting like a Reed valve.

Though if you're mad is still in the stock position it should be having some kind of issue I'd think.
Would it come and go so randomly? I went out for lunch today and drove about 10 minutes and it sounded normal the whole time, that was after sitting for about 5 hours since driving to work.

Also I'm a bit confused by that second sentence, perhaps some typos in there..
 
Fixed, apologies.

It's possible, but unlikely.

Is yours the factory bov or something else? The factory 2g bov is not highly thought of, and is regularly swapped out for a 1g or aftermarket unit.
 
Fixed, apologies.

It's possible, but unlikely.

Is yours the factory bov or something else? The factory 2g bov is not highly thought of, and is regularly swapped out for a 1g or aftermarket unit.
Makes much more sense! Haha it is an uncrushed 1g bov but I also have the BCS restrictor out for a couple extra pounds of boost. I would also think it would have some boost or idle issue.
 
Hmm, I'm not sure why it would act differently on occasion, only thing that comes to mind is different load or rpm situations.
Admittedly I do drive it on the more aggressive side. Except for while it's still warming up in the morning and such so as to let oil circulate. First time I drove the car it was towards then end of the drive when it happened, but yesterday it was only in the morning after a fresh start. I was out and about all night last night and it was normal the whole time. I had a friend offer to let me use his 1G BoV from his talon but I said no for now because the occurence is so random. :cry:
 
So, after continuing to drive the car and doing a little research in the meantime I've come to the conclusion that either my dump tube inside the stock intake pipe is cracked or developed a leak or that replacing the IC pipes and SMIC with one that isn't mangled is now allowing me to build boost to to the point that my BoV is seeing it's limit. Watching the gauge I'm still seeing a fairly steady/solid 16psi give or take a pound or so during 3rd gear pulls however the "whoosh" is getting more consistent and is becoming the norm over the good ole "psh" I've grown used to. With the intentions of wanting at least a big 16g I suppose an upgrade was inevitable so I'll be doing that in addition to the Injen intake in the meantime.
 
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