help?

does anyone know how blow off valve operates?....i know it lets air out between shifts and engine RPM decrees after revving, but how does it know to let the air out? thx......:rolleyes: :D

Anyone correct me on this. After the turbo reaches a certain pressure level which you monitor on the pressure guage, it releases. What I really mean is, you set how much pressure in the turbo and the excess is then released.

At least that is the idea behind it.