I have been following the thermostat debate with great interest.  I have a
question for those who are advocating a thermostat.  Would you also keep the
e-shaft oil thermostat functioning as designed?

Mazdatrix sell pressure regulators for racing to bump up the oil pressure.
Is anyone using these or recommend them?

In other news, I have decided to use the stock waste-gate controller.

It is

light, simple, and sturdy.  It is a simple spring loaded diaphragm open to
ambient pressure.  This means that (as long as the waste-gate is of
sufficient size) it provides boost over ambient, not to an absolute

pressure.

 I think it is about 5-6 psi. (12 mm Hg).  I would think that the turbo

could

continue this modest differential boost up to any altitude I might want

to go

without overspeeding...  I think.  Which brings me to my question:

Would the

turbine speed required to create 5 psi boost at sea level be the same as the
turbine speed required to create 5 psi boost at 20k?

My guess is no, a higher turbine rpm will be required.  In fact its probably
an inverse linear relationship with pressure.  Hmmm.  Does anyone happen to
know the numbers?  It would be fairly easy to shorten the spring and

decrease

the boost a little.  What say you?

Dave Leonard

The pressure ratio will drive the RPM of the turbo.  The fixed delta you
cite becomes a bigger ratio as you climb therefore speed goes up.  What
turbo are you using?  Look at the turbonetics site to get an idea of how
RPM varies with pressure ratio.

Jeff Spitzer

The Mazda turbo Dave has is about the same as a Garret TO-3.

Paul Lamar
 
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