[AREITU]

I've downloaded many videos of high powered 2JZGTEs in various cars, from Clint Pohler's 2JZ Lexus to Veilside's Supra Evolution. One thing that boggles me, is that all of them, when they blow off, it sounds like a loud chirp rather than the "whossh" noise. Can anybody explain to me the reason for this?

 

[Mike Hughes]

The BOVs have to vent out a large volume of air (PV=nRT just like in chemistry class...) in a short amount of time (most drivers don't lift the throttle for very long when they're racing). The BOVs we install are capable of venting out a large amount of air very quickly (if they didn't we'd all suffer from the symptoms of BOV failue - i.e. blown turbos after a while).

The BOV works on the throttle making vacuum differences in the different parts of the engine so if you let off the throttle slowly it'll sound more "relaxed" like a sigh. If you only let up and stomp back down immediately it'll be more like a sneeze.