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Discussion Starter · #1 ·
ok, i think i have the Saab BOV, not too sure about that, BUT here's the problem, if i just start boosting, ie 3000 rpm, and hold the rpm in that range i get a weird sound....kinda hard to describe it...but anyway, it only started happening after i put the Bosch in teh car, now i checked the turbo before and nothing major for shaft play....it also works fine when boosting normally, only when i hold it steady at 2.8K-3.2K about .... so is it just sticking or something? and it being plastic inside u think i'd be safe to just spray some cleaner inside?

Andriy
 

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Is it a warbling kind of sound? That's normal, it's scared the heck out of many of us. :)

The theory is that the membrane inside the bypass valve vibrates as it goes from vacuum to boost. Whatever the reason, it's never hurt anyone yet.

You can hear a recording of this warble here: http://www.supras.com/sogidb/techcenter/images/9653hoot.wav
 

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I could only get mine to go for like 5-7 seconds... scared the shit outta some people though
 

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Just out of curiosity, how do you guys have your Bosch BOV mounted? I have mine the way they are in OE installs (vac nipple horizontal). Most others seem to have them the other way (vac nipple pointed up). I don't think mine makes this noise. I have the Porsche version with the brass diaphragm (I think it's brass). I wonder if there's a noise difference between the two versions.
 

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I have mine with the nipple pointing up and a K&N FIPK. I don't hear the hoot owl noise, but more of a whooshing sound under the hood when on/off the throttle. Its not a chirping BOV sound like you hear on a lot of poser turbo cars, but more of a "rush of air sound".
 

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Discussion Starter · #11 ·
white_mk_2 said:
Just out of curiosity, how do you guys have your Bosch BOV mounted? I have mine the way they are in OE installs (vac nipple horizontal). Most others seem to have them the other way (vac nipple pointed up). I don't think mine makes this noise. I have the Porsche version with the brass diaphragm (I think it's brass). I wonder if there's a noise difference between the two versions.
I think the reason that some ppl hear it and some don't is that some are from Saabs and some are teh Porsches, and the latter ones are the better ones and don't make the sound....i doubt it ha anything to do with the intake setup.

Andriy
 

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one of em have plastic internals, and one has metal internals... funny enough my plastic one outlasted the metal one... im pretty sure the porsche one is the metal one... but yea i have mine with the nipple pointing up, works great :D sounds really good too
 

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Yeah i also have the saab spec one that hoots. But.. someone noted that theirs makes a rushing air sound or "woosh" when operating. Mine does that but it more so flutters than one solid gust. Is that normal? or am i hearing compressor surge? Even with the stock BOV and switching to this one it has always fluttered so i haven't thought anything of it. Haven't ridden in another mk3 to verify the sound either.
 

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