First our static engine RPM was only 5200 RPM.

The 82 inch prop was turning  only 1730 RPM at 5200 RPM so the prop
tips are only going 415 MPH. Normally they get closer to Mach One at
static RPM.

The 82 inch diameter static prop RPM IMHO should be higher. I suspect
the exhaust manifold by pass one inch hole is too large. Our boost
was only 5 psi. IMHO that should be closer to 20 psi.  5 psi is about
the boost you get in a stock 1995, 280 HP RX7 turbo.

We have a couple of heavy duty platform scales and if we measure the
landing gear weights we can calculate the the prop torque and hence
the HP.

We can also measure the static thrust with a calibrated garage door
spring I have.

I suspect the engine was not tuned for prop load.

We know the mixture was too lean as we richened it up and got another
1000 RPM when it was 4000 RPM.

We got it so rich there was raw fuel in the exhaust so it caught fire
after we shut it off. Fortunately no damage to the airplane. Quick
response by a few people with fire extinguishers close by.

We also found the waste gate was beginning to open at this modest
boost level. Very very strange!!!

There are a few things we can try. IMHO make that hole in the
manifold smaller or do away with it altogether.

Nils Castillo has been our Motec guy and he is doing wonderful work.
The Motec system is rather easy to tune as there is a PC USB
interface. Unfortunately it needs to be tuned when the prop is not
stalled.

What would be better is a manual mixture and waste gate controls on
the instrument panel complete with LCD displays of O2, MAP and waste
gate position. Basically a cockpit PC tap into the Motec. Perhaps a
tablet ap would do the trick.

So far the water cross counter flow cooling system is working great
except I suspect we still have steam pockets. It is labeled engine
temperature in the data log attached and never got over 106 degrees
F. The sensor is in the hot pipe coming out of the engine. Obviously
we still have modest HP.

The oil temperature is a little above room temperature and we ran the
engine today six times in the space of two hours. It takes a lot to
heat 4 gallons of oil.

Paul Lamar

Paul,  That sounds very much like a rotary.  Sooo close and yet
troubles. Makes me feel better at least with all the grief I had to
wade through. Neil.

The fundamental problem is you don't know the prop load until you get
the prop on there and fly it. It is a software problem.

If the EFI measured a wide band O2 sensor and adjusted the mixture
accordingly that might work better than using a dyno to set the
mixture. I don't know if a Motec or the one you are using will do
that.

A carb measures the air flow into the engine and adjusts the mixture
accordingly.

All automotive systems use a mass airflow sensor to measure the air
flow and air temperature into the engine.

The air temperature in a turbo installation changes rapidly as the
turbo speeds up. The air is heated as it is compressed.

Check out this chart.

We do not have a mass air flow sensor on the TTC engine. So the Motec
uses intake manifold pressure and temperature to adjust the mixture.
I don't think that works as well as a mass airflow sensor. It might
be hard to find a mass airflow sensor that could handle 650 HP.

Tracy did the same thing in the air but the feed back was too crude
so it could take up to a year to get it right.

I could be wrong about all this and our main problem is that
manufactured hole in the exhaust manifold.  Kyle Mohan that runs a
800HP 3 rotor in the in the drift competition tells me holes in the
exhaust manifold is old school :-)


Paul Lamar

19 years ago able Ibarra got 500 HP out of a turbo two rotor. Then he
got as much as 800.

NOS of course.

This was way back in 1997

Able Ibarra  lives in Riverside Ca. His dad owned a muffler shop in
LA.

He was years ahead of Jim M and knows a lot more about high power
rotaries.

84 inches of Hg!!!!!! at 800 HP.

That is about 20 psi boost. (off my chart :-)) We currently only have
5 psi boost.

We should hire him.

Never the less it will be fixed.

Paul lamar


The current generation of "muscle cars" are all high HP and have mass
 flow sensors.
They might have enough capacity.  Mass flow would be ideal on your TTC engine!

Gary Knutson


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