Blow off valve

ColoradoVolvo · Post by **ColoradoVolvo** » 23 May 2012, 00:57

Not sure if thats even the correct term haha. Anyone put one on their cars? if so what are you using? All my friends are into their jdm cars. They told me it would awesome to put one in my p2 v70x/c. Honestly i have no idea where it even goes.

Mad Dog Tannen · Post by **Mad Dog Tannen** » 23 May 2012, 12:20

It goes on the pressure pipe before the TB. It won't help anything of you have an automatic, it's made to protect the TB, when you have pressure built up in the pressure hose and you suddenly close the TB (like to shift) it releases the pressure so it does not push on the TB and cause wear/damage. It also connects a vacuum line coming from the intake manifold. Aftermarket ones make more noise than stock ones and need to be adjusted to work properly. Manual Trans should already have one. Autos never close the TB all of the way do these are not necessary and don't make the same sound when you shift.

ColoradoVolvo · Post by **ColoradoVolvo** » 23 May 2012, 14:33

So essentially on an automatic it does absolutely nothing and the noise does very little?

RobTarD · Post by **RobTarD** » 23 May 2012, 19:44

You already have a bypass valve the recycles the air back into the intake tract rather than venting it to the atmosphere. Your ECU expects this so when that pressure drop occurs with a BOV you'll be running rich for a moment. It's not really a big deal but keep in mind that your turbocharger will have to re-pressurize the intake after each shift. This isn't much of an issue with an automatic.

If you replace the stock airbox with a cone filter you'll get to hear the bypass valve at work but it's mostly just hissing noises during regular driving.

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ColoradoVolvo · Post by **ColoradoVolvo** » 23 May 2012, 23:25

Alright well thanks for the help. Something told me it didn't seem very legit haha. Great help guys