Subject: dwell
From: rotaryeng
Date: 6/15/2014, 10:43 AM
To: AAA-rotaryeng


Hi Paul

I believe Tracy uses the following dwell settings: RX8COIL
2.6MS RX7COIL        3.5MS LS1COIL        4.3 MS LS2COIL        4.0
MS

Mine is currently programmed for Renesis coils and  reads about 2.4MS
on my scope when running at ~1500RPM. I have D585 coils so I need to
change the programming to 4.0MS, the spark may be a bit anaemic at
2.4MS but it runs.

Cheers

Steve Izett


Good info Steve. Does it stay the same as the RPM changes?

How do you change the program?

Thanks.

Paul Lamar

Paul

Not sure if the dwell changes with rpm/load/?
It is hard coded in the source so needs to be assembled.

Steve

The only way I know how  to get the source, assuming Tracy did not burn the
security fuse, Is dump the binary and disassemble it.
Have you done that? One can then burn a new chip assuming you can decipher
the code :) Probably easier to program from scratch.

IMHO you are better off with the RX8 coils as the GM coil are designed
for half the spark rate. Typical of 2 cycle engines compared to 4 cycle engines.
One reason 2 cycle engines  use CD ignitions.

Tracy had to use draconian cooling methods to keep the GM coils alive.

Paul Lamar

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