Turbo/Blow Off Valve Question

hey, my name is chris
and i have be trying to find this out for a long time. what makes that sound when you shift and start your car that sounds like air boosting out. is that a turbo? or just a blow off valve with a cold air intake? or maybe even something else? if anybody knows please let me know. and also would i need any aftermarket parts to install it?

its not in my car. i go to lincoln tech. that is an automotive school. and a lot of the advanced class kids have it. since i am busy in my classes, as are they. i do not have time to ask them about it. but as they shift its makes a psssssshhhhh kind-of sound. and i think its really cool. i just wanna know what the sound is, and how to get it?

its probably a turbocharger, or to narrow it down, the blow off valve on the turbocharger, and for you to get this noise, you would need a turbocharger, which requires lots of time, money, work, and determination

how long have you been going to this automotive school?

only a few months. ive only completed intro class, and brakes. here is a video link of the sound.
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this is the video. listen to the firt two or three shifts. you hear that high pitch woosh sound.

http://video.google.com/videoplay?docid=-2519828016615291375&q=psi+boost&total=513&start=10&num=10&so=0&type=search&plindex=5

im just curious as to why you went into this field? cuz usualy people that want to deal with cars for a living know a lot about them before they go to school for it. no offense.

Yes, its a blow off valve. In order to have one that works, you must have a turbo system on your car. For the bov to make the signiture "pssshhhh" noise (or however you explained it) you need to have pressure in the charge piping where the blow off valve is located. When you shift **manuals only** you let off the gas and the throttle body closes. That creates a difference in pressure between the charge piping where the bov is and the intake manifold. Since a bov runs off manifold pressure, it will see the difference and open....i hope that makes sense. If not, go to www.howstuffworks.com