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From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: Wastegates
To: flyrotary
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Date: Tue, 17 Sep 2002 20:24:55 -0400
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Posted for <13brv3@mchsi.com>:

>>No wastegate and set up to fly off mp.

Barny MGDQ
---------------------------<<


Can you explain what you mean by this?  Do you mean that you will just allow
the turbo to make full boost, but limit throttle opening to control it?  I'm
currently planning to use a vernier control cable to adjust the internal
wastegate on the Mazda turbo (series 5, 89-91).  The plan would be to leave
it open for the initial tests, then slowly test higher boost levels as I go.

Another wastegate question- Can someone give me an estimate of what sort of
boost I'll have with a fully open wastegate?  In the RX-7 world, they have a
problem with "boost creep" with the stock wastegates, and aftermarket (less
restrictive) exhaust systems.  This is primarily with the earlier TII turbo
(series 4), and the 3rd Gen twin turbos.  The series 5 turbo has a much
larger wastegate than the series 4.  I realize that I might have to port the
wastegate if I really want to be able to make 0 boost, but wouldn't want to
do it if it isn't necessary.

Thanks,
Rusty
Turbo 13B powered RV-3... Be Afraid :-)
1993 RX-7 R1... Stock (for now)


[What you need is a throttle-plate type wastegate like they use on the turboed 
Continentals...  Rayay makes a great one, about 2.25 ID, and it won't break 
your piggy bank if you just get the wastegate and deep-six the controller. 
 You could probably find one on Ebay for a pittance, then have someone make an 
inconel plate for it.  The wastegates sold by Turbonetics (aka Racegate & 
Deltagate) have horribly tortuous exhaust paths and have to cause tons of back 
pressure (IMHO) when used in the wide-open position to free flow the exhaust 
and bypass the turbine.  The throttle plate variety is a straight flow-through 
and is much easier to plumb into the system... it's what I'm planning on using 
ultimately on my 13B.  

            <Marv>                         ]