Re: bypass valve presure openings

["Gary G. Erickson" <erickson@teleport.com>]

glen powell wrote:
 
> On this subject, anyone have anything good or bad to say about
> using a blow-off valve rather than one of these apparently-problematic
> (at above-stock boost levels) bypass valves? Seems like this would be
> the way to go....

Glen,

If I understand you correctly, you're talking about a valve that would
simply dump the excess boost pressure to atmosphere.

The biggest problem is going to be the rich spikes in the fuel mixture
as you dump all that air that has already been measured by the FD. 
While this can result in some really cool noises and flames shooting out
of your tailpipe, it will also cook your cat. in pretty short order.

There is a gentleman here in the NW that has used such a valve to
eliminate the wastegate in his turbo 4kq conversion.  While, it works
for the purpose, it can be quite loud and, IMO, more suited to a car
that is a track toy than a daily driver.

HTH!

Gary

-- 
Gary G. Erickson         Secretary -- NW Quattro Club
 503-702-5789           mailto:erickson@teleport.com
   http://www.teleport.com/~erickson/pnwaudi.htm