BOV
#4
RE: BOV
On a turbo9-3 you can only have a BOV if you have a T5(T stands for trionic)car(red DI cassette from the factory anda MAPsensor). If you have a T7 car (black DI cassette from the factory and a MAF sensor) you can only get an upgraded DV (Diverter valve) and can not vent to the atmosphere. On a T% car you would just disconnect the hose from the DV going back into the intake, plug the hole in the airbox and replace the DB with a BOV. T7 cars can not have that.
#5
RE: BOV
on a 2001 9-3 it will put the car in limp mode, like stated by roto if you put on the bov to a t7. I also have a 2001 9-3 and learned on my own expierence about this, the only thing you would notice first is the check engine light will come on but the car will run normal in good temp. but when its colder out or really hot the car will idle bad and possible through it into the limp mode and that really sucks...so the best things you can do for sound from under the hood is an open cone filter system, you can buy the forge or other brands bpv (but really is a lot of money and not neccassary until you are really starting to get power out of your car) and also take the heat/sound insulation off from the hood....good luck