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sometimes i see cars with a turbo, and when they shift, it makes a sound. It's not a blow off valve sound, its more of a deep sound. I know they have deep bovs too, but i dont think thats it. is that a wastegate valve or something? or is a wategate and bov the same thing? like i heard a saab do it yesterday, and i dont think it was upgraded cuz it was like a old man driving! thanks

 
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Chances are it was the BOV. An open dump WG can make a turbo car louder, but most OEM vehicles have internal closed loop gates. External atmospheric dump wastegates are for real tuners.

 
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They're also illegal

 
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It might have been a recirc valve, instead of a bov.

 
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80% of turbo aftermarket kits out there are illegal.

 
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point taken.

 
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and i love it that way

 
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whats a recirc valve? cuz this guy with a old talon always drives around and his car always sound like that, it only makes the sound when he revs really high and shifts, same as the SAAB. are saab turbos powerful? cuz the guy was flooring it, and all u could hear is turbo! weeeeeeee!

 
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also, i know turbo cars have bov, but just not the ones that let the air out in the the atmosphere. so could this be one of the the BOV, that lets the air back into the engine or something? also, if u have a STI or EVO, and shift it really hard at high rmps, does it make that noise? cuz i've heard it on a evo before too! WEEEEEEEEEEE!

 
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You just defined a recirc valve. It recirculates the boost pressure back into the intake, instead of popping off and releasing it into the atmospthere.

 
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so what does a recirc valve sound like? also, aren't recirc valves better then bovs that release into the atomosphere? Also, do stock cars come with recirc valves? do they make any sound?

 
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A recirculation valve sounds like a muffled blow off valve basically. They arent better, but they are legal. Stock turbo cars come with recirculation valves, because even though the air has only been compressed and not yet entered the engine, it is still illegal to let it back into the atmosphere because some emissions laws are just stupid.

 
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so is that the sound im hearing on for example, a EVO when it shifts really high and hard?

 
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anyone

 
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That should be the only thing making noise during a shift, so probably