[Diy_efi] A/F mixture, EGT and engine damage
michael at fastmail.ca
Mon May 16 18:08:45 CDT 2005
> I have heard that going too rich can damage the engine
> by "washing" the oil film off the cylinder walls. Is
> there a safe lower limit on A/F or EGT ?
If there were a magical number that gave you the best economy or the
best power for all engines then the numbers would be well published and
recited by everyone. Your 13.2 number sounds like a happy medium
between cruise and power.
Personally I would try going a little richer under load and a little
leaner under cruise. Some engines don't mind being run high into the
15's for cruise but others will not tolerate it at all. Some engines
make more power NA into the 12:1 AFR but some are better run lean
around 12.8:1 or 13:1. Everything is a balancing act. If your EGTs are
too high try advancing the ignition and/or richening it up a little.
I wouldn't worry about washing the cylinder walls at these ratios. Run
it 10:1 and richer and you could have a problem.
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