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Mark:
I think what is happening is that the thetaPP is changed less by the loss of the mag than by the loss of the EI. This had little to do with the amount of fuel being burned.
BTW, I just looked at the thetaPP data on a set-up where the timing was changed by as little as 2 degrees, advanced. The thetaPP was advanced to 10dATDC and the peak pressures were above 1100 psi. This is not a good thing. You guys do as you please, but that's not something I want to do to my engine. Spark plugs begin to be blasted out of cylinders at 1200psi--by imperical experience.
These are observations of hard data.
Walter
On Jan 8, 2008, at 2:23 PM, Mark Ravinski wrote: Hi Walter, When one shuts off the mag and runs on the EI, (during cruise), there is some small increase in EGT and decrease in CHT. Then when one shuts off the EI and runs on the mag alone, there is a much more dramatic shift in the same direction as before. I believe that the vacuum advanced EI is doing a much better job of burning more of the fuel in the cylinder. (again, at reduced power settings where we spend most of out time and fuel (assuming normally aspirated.)) I've used three different brands of EI's and have had similar results in this regard. Please don't ask for hard data - I only have observations. Mark Ravinski ----- Original Message ----- Sent: Monday, January 07, 2008 3:51 PM Subject: [LML] Re: One mag, One electronic ignition
How does that become evident? Please explain.
Walter
On Jan 7, 2008, at 10:31 AM, Mark Ravinski wrote: Also, a common test is to shut off each system alternately and look at CHT and EGT. It becomes evident that the EI is burning more of the fuel in the cylinder and the straight mag is burning more of the fuel in the exhaust header.
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