I have a "Legacy" EFII Dual Ignition only (no injection) on my Parallel valve standard 8.5 compression O-360 with a fixed pitch Catto Prop. I've flown almost 300 hours behind the canned ignition curve with no problems per say, but I don't believe it is optimum for my situation.
I generally takeoff full power 2100 static RPM and climb at full power ROP and 130 KIAS. After level, accelerate and CHT's below 400 I pull power below 65% and adjust the mixture to LOP. I have to manipulate the throttle somewhat to achieve an EGT spread within 80*. I also burn 91 Mogas in 1 tank during cruise when available.
Here is my canned ignition curve super imposed in purple on Nigel Speedy's graph from his article in KitPlanes Magazine "The effects of ignition advance on cylinder heat temperature, speed and efficiency."
I'm thinking my canned timing curve is a bit aggressive with the oversquare condition with my fixed pitch prop during climb resulting in higher engine temps. I would appreciate any input on my proposed timing curve anyone has to offer. I have spoke to and appreciate Robert of EFII who has consistently fielded/answered my numerous questions via phone and email for the past several years.
My current ignition curve is currently controlled by RPM and Manifold Pressure together.
The current RPM curve is shown in the shaded yellow column 30 degrees above 1250 RPM, my proposed timing curve keeps timing at 25 degrees BTDC above 1250 RPM.
My current ignition curve uses a 4 degree retard at higher manifold pressures tapering down to 0 retard at 24.1, set timing as 30 degrees BTDC above 1250 RPM. With my proposed timing curve of 25 degrees BTDC I would start an ignition advance similar to Nigel Speedy's compromise timing curve shown in the first graph. 1 degree advance starts at 24.6 inches manifold pressure and levels off at 6 degrees of advance at 22.3 inches of manifold pressure for a total of 31 degrees of ignition advance. I'm initially limiting the advance close to what I've been flying the last 290ish hours.
Robert suggested a value at the low end of the manifold pressure range in case of a manifold pressure sensor failure, I picked 0 degrees to keep timing at 25 degrees.
Thoughts, suggestions and ideas appreciated!
I generally takeoff full power 2100 static RPM and climb at full power ROP and 130 KIAS. After level, accelerate and CHT's below 400 I pull power below 65% and adjust the mixture to LOP. I have to manipulate the throttle somewhat to achieve an EGT spread within 80*. I also burn 91 Mogas in 1 tank during cruise when available.
Here is my canned ignition curve super imposed in purple on Nigel Speedy's graph from his article in KitPlanes Magazine "The effects of ignition advance on cylinder heat temperature, speed and efficiency."
I'm thinking my canned timing curve is a bit aggressive with the oversquare condition with my fixed pitch prop during climb resulting in higher engine temps. I would appreciate any input on my proposed timing curve anyone has to offer. I have spoke to and appreciate Robert of EFII who has consistently fielded/answered my numerous questions via phone and email for the past several years.
My current ignition curve is currently controlled by RPM and Manifold Pressure together.
The current RPM curve is shown in the shaded yellow column 30 degrees above 1250 RPM, my proposed timing curve keeps timing at 25 degrees BTDC above 1250 RPM.
My current ignition curve uses a 4 degree retard at higher manifold pressures tapering down to 0 retard at 24.1, set timing as 30 degrees BTDC above 1250 RPM. With my proposed timing curve of 25 degrees BTDC I would start an ignition advance similar to Nigel Speedy's compromise timing curve shown in the first graph. 1 degree advance starts at 24.6 inches manifold pressure and levels off at 6 degrees of advance at 22.3 inches of manifold pressure for a total of 31 degrees of ignition advance. I'm initially limiting the advance close to what I've been flying the last 290ish hours.
Robert suggested a value at the low end of the manifold pressure range in case of a manifold pressure sensor failure, I picked 0 degrees to keep timing at 25 degrees.
Thoughts, suggestions and ideas appreciated!
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