Re: Boost

[Jay Carter <JayC@RebelRednecks.Com>]

At 08:23 PM 12/1/2000 -0800, you wrote:
> I am hoping that one of you GN guys can clear up for me what the difference
> is in a Blow off valve & a Waste gate.  the obvious is that the blow off
> valve is on the "clean" air side & the waste gate is on the "exhaust" side.
> my guess is that it has to do with response time issues & volume of air.
> but as the typical waste gas is an active device & comes on more as the
> boost comes up.  i would not think that it would happen all of a sudden &
> something else would have to dump the extra pressure.


A blow off valve is to bleed air from the compressor spike when you slam 
the throttle body shut. It's supposed to stop you from damaging your turbo. 
However, in talking with people who build turbos and have been in the 
industry for a very long time, it's their feelings that the blow off valves 
available to people like us don't really serve that purpose because they 
react too slow.

A wastegate goes in the exhaust stream before the turbo and is used to 
bleed exhaust gas out of the system as to control your boost level. Most 
wastegates don't start opening until you get close to the desired level of 
maximum boost. If they opened sooner, you would experience lag. Most 
external gates that I have tested start opening about 5-6 PSI before max 
boost is reached.



Jay

Jay Carter
JayC@RebelRednecks.Com
Jay@BoomGames.Com

TUCB Technologies Corporation
Senior Editor - BoomGames Division
www.boomgames.com

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