Overhaulin'

How does a modified car (especially import) make that "releasing compressed air" sound when switching gears?

Public Comments

1. if it has a blow off valve (and is manual.)
2. Yes, a valve on the turbo releases air when the pressure builds to more than the engine requires. Mainly between gears when shifting a manual transmission. You can buy louder pop-off valves if you think the sound is "cool". Just like if you think it is "cool" when your 4 cylinder sounds like a lawnmower when you put a crappy muffler on it with a 4 inch outlet. YEY!
3. its the sound of the blow off valve. This is unique to turbo charge cars, to release the extra pressure from the turbine. Some car makers with turbo charger engine does not make the sound because excess boost is cycled back in the combustion cycle. Certain type of blow valve makes a popping firecracking sound instead of the whoosh. auto turbo cars makes the sames sound also when it changes gears.
4. If it have BOV and SQV. Did you know ,cars without turbo can also install BOV(Blow of valve). SQV: If you have saw the movie "2 Fast 2 Furious",you will notice that Nissan Skyline drove by Brian O'Conner(Paul Walker)realest smoke or fire(some time) in his front bumper of his Skyline.That is SQV.