Originally Posted by boostinpsi
correct me if im wrong if the bov is adjusted correctly there shouldnt be any vacumn issues because the valve would be closed at idle.
im not saying i am going to do this im just looking at options. im not going to put a part on my car just for sound it would most definatly be a purpose built.
i want my car to run at its best but i don't want all go and no show.
The stock valve on both the EVO and scooby is open at idle, so adjusting the valve to be closed at idle takes more spring pressure. That extra spring pressure keeps the valve from opening properly on shifts and leads to compressor surge on throttle lift. The one and only purpose of the BOV is to vent this air preventing compressor surge on throttle lift, and most of the aftermarket VTA valves compromise this purpose in order to get a cool sound.
As Warrtalon stated, you get a lot more of the BOV sound when you go to an open element cone style air filter. You can keep the stock pipe from the MAF sensor to the turbo, and just replace the air box with a cone filter and you will have plenty of sound from the BOV.