Re: bypass valve presure openings

["Avi Meron" <avi@cosmoslink.net>]

Brendan,
Sorry, I Thought you had a problem with the bypass valve concept.
As for the overspinning, I really don't know, from my experience of tearing
down countless turbos (mostly big ones), I never saw an oversppining (that I
was aware of?..), so I don't know. I think it is fair to assume that it is
not a big issue since almost every mfg.. uses some sort of bypass (including
Audi),
Avi
-----Original Message-----
From: Brendan Rudack <rudack@umcc.umcc.umich.edu>
To: Avi Meron <avi@cosmoslink.net>
Cc: Quattro <quattro@coimbra.ans.net>
Date: Wednesday, January 28, 1998 11:10 PM
Subject: Re: bypass valve presure openings


>On Wed, 28 Jan 1998, Avi Meron wrote:
>> flow to turn the turbine), it only coasts when you let go of the pressure
/
>> throttle, also it is NOT vented to the atmoshere, it is vented to the air
>> box in.
>
>Avi, I was referring to Gary's explanation of his friend's 4ktq which is
>being run with a blow-off valve and no wastegate. Ok, Throttle plate
>shuts and blowoff dumps excees pressurized air,  wouldn't there be a
>momentary turbo overspeed until pressure from last few piston strokes and
>exhaust manifold pressure clear out through the turbine since there is no
>wastegate? And might it be exagerated when the blow-off opens reducing a
>lot of the resistance on the compressor side?  Or are the pressures in the
>EM too small to do that to a turbo spinning at ~100k rpm's?
>
>
>Brendan Rudack
>