keeps your turbo spooling during shifting and brakeing so you dont bog down your engine or get any boost lag. it also looks fucking cool when flames shoot out your tail pipe and sounds awesome when it goes bang! bang!
if you have ever watched the world rally championship you probably saw that. it may be hella cool but dont get one, it fucks up your turbo hella fast. also its not legal and its fucking hard to find one. WRC cars have them because they only use the car for a week before they get a new car. it is also known as an ALS or Anti-Lag System.
