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  #11  
Old 02-13-2018, 08:42 PM
crabandy crabandy is offline
 
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I fired up the programmer and found out that I do have the EM-5 with an older software version, with the current software I can have the LOP functionality.



I watched some videos online about the controller and found after scrolling through the menus and verifying my current settings made me comfortable operating the controller. I left the low RPM timing set at:
500--10*
750--15*
1000--20*


I Changed Higher RPM 1250 and up to 23*. I input the advance schedule below.



A couple flights later left me more confident in experimenting with the timing and a little head scratching. I flew the same manifold pressure advance schedule at both 23* and 25* RPM timing above 1250 RPM.
Test flights were take off, set 90 KIAS engage autopilot on IAS/HDG to be established prior to 2000 PA where I timed the climb to 7000 PA. LOP was at 7500 and 21" map. Not enough data by any means to average out my results but here's my initial observations. 25* ran better throughout the range with:
-better idle
-10 seconds less time to climb 1000-7000 PA
-Approximately 10* less CHT
-Smoother and further LOP
-(From memory) Stock EFII curve was similar CHT's and way better LOP

I can only adjust 1 ECU at a time with my current boxes, I decided play with the timing of 1 ignition while on the ground for the lower RPM's. My airplane has always had a dead spot from 700RPM to 1000RPM when slowly applying throttle. I notice the dead spot when adding power to taxi from idle and when power is all the way back in the pattern and I need to add a smidge of power in the pattern. I always assumed that I wasn't moving the throttle fast/far enough to properly engage the accelerator pump of my carb. I played with the timing from 10-40* and found 750 RPM and up that 25* timing with the 7* manifold pressure advance (32* total) seems to give the smoothest running idle. The dead spot between 700-1000RPM seems to be gone. The timing advance increased my idle 200ish RPM and things were too hot to adjust it back to 500 and play with timing there.

TooBuilder has some good advice about playing with the timing "in situ." I plan on playing with timing on 1 ignition and recording values and tweaking as I go. Good news is I get to do a lot more flying, about that time and money......

If I find the best timing value for advanced timing with 1 ignition is there a ballpark change in timing that will occur when both ignitions are set to the same advance? For Example if my engine performs best at 25* on 1 ignition adding the second ignition should roughly change the value by how much?
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Last edited by crabandy : 02-13-2018 at 08:49 PM.
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  #12  
Old 02-13-2018, 10:47 PM
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Toobuilder Toobuilder is offline
 
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The ballpark difference I experienced was 3 degrees between a magneto and the single CPI at "optimum". I'd expect you will see less than that
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  #13  
Old 02-14-2018, 09:15 AM
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Quote:
Originally Posted by crabandy View Post
A couple flights later left me more confident in experimenting with the timing and a little head scratching. I flew the same manifold pressure advance schedule at both 23* and 25* RPM timing above 1250 RPM.
Test flights were take off, set 90 KIAS engage autopilot on IAS/HDG to be established prior to 2000 PA where I timed the climb to 7000 PA. LOP was at 7500 and 21" map. Not enough data by any means to average out my results but here's my initial observations. 25* ran better throughout the range with:
-better idle
-10 seconds less time to climb 1000-7000 PA
-Approximately 10* less CHT
-Smoother and further LOP
-(From memory) Stock EFII curve was similar CHT's and way better LOP
Interesting.

Climb is with mixture parked on full rich, or leaning to maintain best power through the climb? What was climb RPM?

Is 21" your WOT manifold pressure at 7500?

I would expect the stock EFII schedule to be a little better LOP at 21" as compared to the 23+5 schedule, because timing is 28 vs 30. It's hard to imagine how the EFII schedule can be way better than the 25+5 schedule, as they're the same timing, 30 BTDC.
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  #14  
Old 02-14-2018, 10:43 AM
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Toobuilder Toobuilder is offline
 
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In my opinion, ignore LOP performance until you have the capability to manually select that condition. Tuning an overall curve for LOP will always mean you are too advanced for best power mixture. The opposite is true of course. Best power timing will be too retarded for LOP. It's the fundamental flaw in the "one size fits all" approach to timing.

You can certainly play with the LOP advance as a knowledge exercise, but call Ross and get a reflash before you try to execute a new curve
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Michael Robinson
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Harmon Rocket II -SDS EFI instalation in work
RV-8 - Flying
1940 Taylorcraft BL-65 -flying
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  #15  
Old 02-14-2018, 12:54 PM
crabandy crabandy is offline
 
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Interesting.

Climb is with mixture parked on full rich, or leaning to maintain best power through the climb? What was climb RPM?
90 KIAS, leanest cylinder was leaned to 100ish ROP and climb RPM 2100ish. I never fly this configuration, just wanted to start somewhere. I need to do multiple climbouts at the different ignition advances, usually 130 KIAS.

Is 21" your WOT manifold pressure at 7500?
Throttle was pulled back several inches, to even out EGT’s for LOP. My mixture distribution at full throttle is horrible, 150-200 degrees between richest and leanest cylinder.

I would expect the stock EFII schedule to be a little better LOP at 21" as compared to the 23+5 schedule, because timing is 28 vs 30. It's hard to imagine how the EFII schedule can be way better than the 25+5 schedule, as they're the same timing, 30 BTDC.
The advance schedule I plugged in has 4* of advance at 21” MAP, 23* base gives 27* total advance and 25* base is 29* total. 20” MAP would’ve given me 30*. Splitting hairs for sure, but 7500 and 21-22” was a good setup LOP prior. As I think about it more, I left the mixture LOP for the descent and it was smooth all the way down. Below 18” MAP gave me 30* with a 23* base timng and 32* at 25* base timing.
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Last edited by crabandy : 02-14-2018 at 12:57 PM.
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  #16  
Old 02-14-2018, 01:07 PM
crabandy crabandy is offline
 
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Quote:
Originally Posted by Toobuilder View Post
In my opinion, ignore LOP performance until you have the capability to manually select that condition. Tuning an overall curve for LOP will always mean you are too advanced for best power mixture. The opposite is true of course. Best power timing will be too retarded for LOP. It's the fundamental flaw in the "one size fits all" approach to timing.

You can certainly play with the LOP advance as a knowledge exercise, but call Ross and get a reflash before you try to execute a new curve
I agree the LOP switch is the best way to get the most out of ROP and LOP and the software flash is in my future. Meanwhile Iíve got a X/C trip this weekend which should give me lots of opportunity to play with timing in cruise at various power settings and altitudes.
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  #17  
Old 02-14-2018, 02:49 PM
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Sure. Cross country time is a good opportunity to play. Lots of time to let it really stabilize after an adjustment. Even with one ignition with the adjustment you should be able to get very close to your final number.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

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RV-8 - Flying
1940 Taylorcraft BL-65 -flying
PA-20-inspired "family truckster" -in work
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