At cold idle you would want a much richer mixture than a warm idle. I cannot see the changes if any, even though I have a big screen. Street cars bias pulse width with data from the coolant temperature sensor.

 

Timing at cold start could be 20 degrees and once you have a start could go to 22 degrees.

22 degrees is plenty until you are close to cruise power.  Then as you lean to cruise mixture, the timing can go up a bit to account for the leaner (slower burning)  mixture.

 

For closed throttle above idle RPM descents you can go up to 40 degrees of advance.

Idle fuel flow but at high RPM you need extra time to burn the idle mixture (the Renesis goes to 44 degrees), to keep the heat in the rotors and prevent unburnt fuel from entering the exhaust and muffler, lest the fuel ignite with surprising power and a big flame ball. Very impressive in a race car but too spectacular for aviation use.  

 

I would not put much faith in a F/A gage during throttle or RPM transitions. At any RPM point if the pulse width and fuel pressure didn't change then the mixture didn't change.

 

You will or may detect RPM/mixture combinations that report unhappy tuning when you pass through various combinations of tuned length/back pressure/timing settings. You can have cold air entering the muffler and flowing quite a distance through it in some cases. Not so much in Renesis engines with no overlap. Same thing around the oxygen sensor, where gasses that have passed over the sensor come back over it in the opposite direction.

 

So EGT probes and oxygen sensors are mounted on the outside of curves where possible.

 

Never a problem in long exhaust systems.  Airplanes tend to have very short exhaust systems.

 

For full power tuning go too rich first. It is hard to hurt or stop a rotary from too rich a mix.

Peak EGT is not good for apex seals. So stay rich of peak or well lean of peak EGT.

If you tune too lean the engine will shut off just like the ignition was cut. Just like your engine dying at idle. Just go richer and base it on coolant temperature.

 

Just a guess though.

 

Lynn E. Hanover

 

 

Last night I turn the sound recorder on the laptop on while I did a
tuning run.  I played back the data in MegaLogViewer while recording the
screen, and then matched it up to the sound.  I was hoping I could get
suggestions for improving the tune.

The first issue is the hard start.  The only time I purposefully turned
the engine off was at the very end.  It runs pretty smooth, once it is
warmed up to about 120*F, but below that the AFR will go off one end of
the scale or the other, indicating that fuel isn't getting burned.

http://www.youtube.com/watch?v=F3pYW1lOcTo&feature=youtu.be

The top graph has RPM, manifold pressure and throttle position.
The second graph is injector pulse width time, AFR, and fuel flow.
Spark advance is on the third, along with mapDot and tpsDot.  Those are
measures of how quickly the map and throttle position are changing.  The
computer uses them to calculate how much to extra pulswidth to add on
acceleration.
The bottom graph show the oil temp, coolant temp and manifold air temp.
Instantaneous values for each line show up at the center bottom of each
graph.
The last line at the bottom is a run time timer.

The bouncy balls to the right are the tables that the computer uses to
calculate the injector pulse width and spark advance.  Lowering the
numbers in the VE table tells the computer that the engine isn't sucking
as much air as theoretically possible, and the computer will lower the
amount of fuel at that combination of RPM and manifold pressure.  If the
ball is between cells, it uses a weighted average of the adjacent ones. 
It just pulls the number from the spark advance table and sends it to my
EDIS modules.