This is an experimental technique for pre tuning
Tracy's EFI computer based on using an engine
simulator. You don't need to run the engine.

A new chart is constructed using a CAD program like ACAD
or Rhino for each engine max HP and each injector flow
rating in pounds per hour.

Set up the simulator using the auto parts
store vacuum pump set to 15 inches of Hg.

Estimate max HP. In this case I am guessing it will be around
250 HP. Know the max flow in pounds per hour of the injectors
used. In this case they are are about 33 pounds per hour
so the primary injectors are wide open at 80% duty cycle.
Total supply on the right side of the graph is therefor
66 pounds per hour at 15 inches of Hg. You can then read
off pulse widths in percentage of max pulses width by
referring to this chart. I think :)

This is all based on a linear relationship between
HP, RPM and intake manifold pressure. As such it is just
a crude estimate of the mixture. Final tuning will be
done in the air.

This technique needs to be refined. This is just mostly
an idea at this stage. I thought I would upload it so people
could think about it and make some suggestions for improvements.

A big problem I am still thinking about is how to represent
the secondary injectors. Also what happens when the secondary
injectors are first activated or staged as it is commonly
called. I'll know more about staging when I see what
Tracy's computer does when staging occurs by monitoring
the primary and secondary pulse widths using an oscilloscope.

Paul Lamar


The Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2005 All world wide rights reserved.