In a car that is equipped with some sort
of forced induction system
,such as a turbo
or a supercharger
, a blow-off valve is usually availible as an aftermarket part to release excess pressure
(boost) from the turbine
system. Makes a very distinct noise. Like - pssssshhhhhhhhh! Or somtimes a chirping noise depending on the blow-off valve. Usually replaces a stock part usually refered to as a by-pass valve.
1. Gil: Whoah, dude! Did you hear that
car go by?
Willy: Yeah, it sounded like it had a blow-off valve.