Here are some sounds of certain Blow Off Valves on miscellaneous cars. 

The different BOVs give a whistle or a "whoosh" sound to the expulsion of excess boost.

*NEW*

If anyone can identify these people please email me so I can give credit where it is due

(found at www.935motorsports.com/bovmultimedia.htm )

Click on picture for sound

This site is meant to give information related to the 1993 (o)Mazda RX-7 Twin Turbo.  Anything from rotary engines to wiring diagrams and turbo upgrades to tuning info, this site has it all! efini 93 rx7 13b anfini Turbo RX-7 Turbo RX7 turbo rx7 rx7tt rx-7tt  As well as the Rotary Engine Pickup Truck aka REPU repu