I just bought a new Mini Cooper S a few months ago. The S has a 168hp supercharged engine.
When I'm driving normally or accelerating, and I quickly let go of the accelerator (happens often, braking for stop lights etc), I often hear one or two 'poof' 'poof' sounds coming from the engine/muffler. It's not very loud but definitely noticeable.
What is the origin of this sound? Is this normal on this engine or on a supercharged engine?
2007-02-06 19:22:49 · 3 answers · asked by lei514 1 in Cars & Transportation ➔ Other - Cars & Transportation
What happens, is that the supercharger is always compressing air, and if the throttle is closed, theres nowhere for this air to go, so it just compresses the gas (which would get very high pressure very fast. in turbos it just slows the turbo. in supercharger, it would put strain on the supercharger). What the whoosh is is the valve that lets off this pressure. A blowoff valve blows the pressure into the air. A diverter valve reverts it back into the intake (so you dont discard this compressed air). Im not sure how the mini is set up exactly, but it prob has a diverter valve on it somwhere.
thats how centrifugal blowers work at least, which i think the mini has.
hope that helps you.
2007-02-06 19:41:54 · answer #1 · answered by Kyle M 6 · 2⤊ 0⤋
It is probably some type of valve like a waste gate to release pressure from the supercharger.
2007-02-06 19:27:39 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Sounds like its unloading. The pressure from the supercharger is no longer being sent to the motor since you let off the accelorator.
2007-02-06 19:37:18 · answer #3 · answered by the Animal 3 · 0⤊ 0⤋