Top Definition
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.
by Wilburt April 28, 2006
Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.