Surefly mag - any advantage if I can't run Lean of Peak ?

ChopAndDrop

ChopAndDrop

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ChopAndDrop
Just a "thought experiment" but one of our Mags is old and probably due to be replaced or rebuilt soon.... discussion came-up amongst us owners if its worth replacing this with a Surefly electronic mag. Our engine+airframe is on the application list that we could replace one of the mags (The side being replaced is with the impulse coupling).

This is on a Beech Sierra, I know that's uncommon airframe around this forum, but this is an IO-360 engine (fuel injected) so a common engine shared across other airframes, anyone else with IO-360 can chime in with your experience?

I've been reading on line and results seem to be mixed as to what advantages I would really see from this: the people reporting slightly lower GPH fuel-burn in cruise seems to be correlated with running Lean-of-Peak, or people who had Carburetor engines.

I checked my PoH and the specified leaning procedure requires me to be 25-degress or more on the Rich side of peak, our PoH specifies operation "only on the rich side of peak".

So given that, is there still any advantage (e.g. fuel burn in cruise) to an electronic ignition?

(Our engine is easy to start cold-start, no warm-start problems; so the "easier starting" benefit that is claimed is always nice but is not really a driving factor for us ).
 
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Do you have fine-wire plugs? I did and ran into issues with a Surefly that the company attributed to the fine-wire plugs. I was unwilling to switch back to the original plugs.

Great customer service at Surefly though. And I suspect some were able to make it work with fine-wire plugs. Just not me.
 
> Flying your IO360 at 25° ROP puts you in the red box and thus towards operating at highest internal cylinder pressure (usually around 50°ROP)

Understood, I don't cut it _that_ close, I have an engine monitor and usually run ~50 degrees RoP.
My PoH says the Cruise lean procedure is to go 25-50 Deg Rich of Peak, that all performance charts are done at 25° ROP.

Patrick said:
Why not fly LOP?
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The only answer I can give you is "because my Aircraft's POH prohibits it".
I can appreciate that's not a great _Technical_ answer, given all the other info out there about running LoP, but: that's the Legal / Checkride / "insurance claim" type of answer.
 
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Does your POH prohibit LOP operation? What do Lycoming’s publications - updated since the plane was built ~45 years ago - say about it?
 
ateamer said:
Does your POH prohibit LOP operation? What do Lycoming’s publications - updated since the plane was built ~45 years ago - say about it?
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https://www.lycoming.com/sites/default/files/O-HO-IO-HIO-AIO & TIO-360 Oper Manual 60297-12.pdf

Last revised 2005. Leaning starts on page 3-5. There is serious disagreement between what Lycoming says and what Deakin and Busch say. Lycoming has to bear the liability and reputation for their engines, and for what they tell you to do; Deakin and Busch don't.
 
It’s a lot of coin for a solution looking for a problem.


Ask yourself what the fuel savings would be running one, the cost, then what using that same cash for fuel only. Put it on an xy axis and determine where the break even point is on hours flown. Then look at your average hours per year and determine if you will be keeping the plane that long.
 
Probably gain more by not upgrading the mag and just diving into LOP ops. Nobody’s POH from that era says it’s okay but if it’s injected and instrumented, you can do it. You will save $$$.


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ChopAndDrop said:
>
The only answer I can give you is "because my Aircraft's POH prohibits it".
I can appreciate that's not a great _Technical_ answer, given all the other info out there about running LoP, but: that's the Legal / Checkride / "insurance claim" type of answer.
Click to expand...
Can't imagine the Law, a DPE or your insurance Co. cares if you're LOP. There was no such thing a a GAMI spread nor engine monitors when your POH was written.
 
ChopAndDrop said:
The only answer I can give you is "because my Aircraft's POH prohibits it".
I can appreciate that's not a great _Technical_ answer, given all the other info out there about running LoP, but: that's the Legal / Checkride / "insurance claim" type of answer.
Click to expand...

So the prohibition is in the limitations section?

Or is it somewhere else in the flight manual?
 
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