Just got this note from Greg:
"My old notes show a TO-4E housing with a 55 compressor and P

trim.  .81

A/R

ratio.  The rationale was for a pressure ratio < 3.0.  Given that

MAP is

dropping with altitude,

but our need for power is also dropping, we can use this turbo to

provide 250++ HP for takeoff

while pushing a relaxed 180 HP through the air at altitude.

This is like flying a IO-360 on the deck except with less drag at the
higher elevation, so your TAS is much higher.  The .81 A/R keeps

you out

of

the surge range and in the middle of the 55 map.  A 1.0 A/R pushes you
closer to the edge of the map than I'd like to see."

I had also sent Greg a copy of Cliff Manzke's turbo notes from the

Rotary

Engine Best Practices site- 29/APR/2001, his comments were:

"I agree, as you know,  that a wastegate is decorative dead weight, but
disagree with his need for a larger intercooler.  He is making the same
error I made that you can avoid: cooling all the charge air.  Put your

POV

_ahead_ of the cooler and cool only what you intend to run through the
rotorset." [POV = intake manifold Pop Off Valve. Limits intake
manifold pressure]

So there you have it finally....

"TO-4E housing with a 55 compressor and P trim.  .81 A/R ratio."

...Chrissi

Cozy Mk-IV 13B-turbo
www.CozyGirrrl.com
Chrissi@BlueMountainAvionics.com

Thanks Crissi

Paul Lamar

Is there a way to extrapolate this for the 20b?  I'm assuming the .81 A/R
ratio and TO4E housing would stay the same.

Thanx a bunch Chrissi.

Barny MGDQ

-Mark Steitle wrote:

As I recall, Chuck Harbert's 20B was turbo charged.  Maybe the person that
bought Chuck's engine package can provide the specs on that turbo?
Mark

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