We are finding it a bit difficult to set the mixture using Tracy's computer on the dyno. In an aircraft at low altitude there is a much simpler set of situations where intake manifold pressure is strictly a

function of throttle opening. On a dyno the load can be varied over a wide range. Tracy's in the air method of setting the map works quite well but it is less well suited to a dyno situation.

Never the less we got one useful data point where the throttle was 3/4

open at 5250 and intake air temp of 84 degrees F. The HP was 148. BSFC

was .53 and EGTs were 1402 and 1477. EGTs were down about 100 F from peak 1532 and 1580 The air:fuel mixture was about 15:1
Unfortunately the mixture knob was set to full rich at that point.
We were using the default mixture settings.

Frankly I am not entirely sure what we are going to do next.

Paul Lamar

Aren't you going to start bumping up the injector map settings?  It
makes sense that the default settings are too lean for a PP right?

I think many of us are waiting eagerly for results.  Keep up the good
work Paul.

Hans

Well Dave Lemon is getting a bit apprehensive. He has not been paid yet.
This engine is easily capable of destroying itself if it is not properly
loaded at high RPM. Mixture could go very lean at 12,000 RPM or higher.
He is rightly concerned. Most of his dyno experience has been with carbs
that usually provide a near usable mixture setting throughout the power
band. Also carbs tend to have a moderate throat size to provide a good
fuel signal at the low end. This tends to limit HP and RPM at the top
end compared of course to say; a p-port with a slide throttle. In an
airplane the load is always there. The prop runs into a load brick wall
around 2700 RPM which of course limits the engine RPM to 2.85 times that
or 7700 RPM.

I am debating with myself if we should move the engine to a prop dyno
which is more suitable for setting the mixture using Tracy's programming
methods.

Paul Lamar

Congrats on getting this far, Paul! Have you set the injector flow rate
setting on the ECU? I don't recall which function that is on the ECU,
but it must be set correctly before doing anything with the map table.
It might need to be different than stock with your custom injectors. The
manual mixture knob has lots of authority, you should be able to get
rich enough with that without tuning the map first, I think. Where are
you picking up the manifold pressure for the ECU sensor?
I hope you can get this going, and I wish I could get out there and help
or at least watch! With a prop dyno, you are not pressured to get tuned
so quickly, once you are happy you could then move back to Dave's dyno,
just a thought.

Chuck

I think it is mode 3 and we are going to try that this afternoon.
The EM2 would be ideal but none are available until August.

Paul Lamar