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Old 12-06-2018, 06:29 PM
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Toobuilder Toobuilder is offline
Join Date: Jul 2009
Location: Mojave
Posts: 4,348

Originally Posted by DanH View Post
You're suggesting the ability to program timing retard at WOT as compared to the typical aircraft magneto's fixed compromise timing?

One of many conflations of spark generation with spark timing

the merging of two or more sets of information, texts, ideas, etc. into one.
Indeed. I was following (what I perceived as) Ross' lead off the stale "Hotter spark = higher HP" path and onto the real benefit of a "good" EI. "Good" in this context is one that can be configured to optimize the timing event for each engine.

So in my mind, no conflation here. It was a conscious abandonment of the original question.
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.

Michael Robinson
Harmon Rocket II -SDS EFI - Flying
RV-8 - Flying
1940 Taylorcraft BL-65 -flying
1984 L39C - flyable, available for sale
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Old 12-06-2018, 07:19 PM
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rv6ejguy rv6ejguy is offline
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,321

I want to add that a truly weak spark may not light off the mixture-especially if that mixture is very lean or very rich, however, on a standard 8 to 1 Lycoming, at 2700 rpm, WOT at SL, a standard mag, in proper operating condition, has no problem doing that job.

Yes, I've had to suggest to some of our automotive drag racing clients running SDS ignitions, to shrink plug gap to be able to run very high boost pressures. In one case I recall, the spark wouldn't jump a .035 plug gap running something like 150 inches of manifold pressure. We shrunk the gap to .025 and all was well again. This engine was producing 391hp/ L on the dyno which would be the same as a 360 Lyc making 2345hp.

Inductive discharge ignitions certainly have their finite limits but you won't be anywhere close to them with a naturally aspirated Lycoming engine, even with 12 to 1 pistons using a mag or most EIs having a coil with suitable inductance, turns ratio on the windings and being properly saturated (correct charge time).

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 434.4 hrs. on the Hobbs,
RV10 95% built- Sold 2016

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Old 12-06-2018, 07:52 PM
jump4way jump4way is offline
Join Date: Sep 2008
Location: Coolidge, AZ
Posts: 329

Originally Posted by rv6ejguy View Post
This engine was producing 391hp/ L on the dyno which would be the same as a 360 Lyc making 2345hp.
Where do I find this Lycoming?
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Old 12-06-2018, 07:55 PM
Kyle Boatright Kyle Boatright is offline
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 3,836

Originally Posted by jump4way View Post
Where do I find this Lycoming?
If HP is your primary interest, here's the Lycoming for you:
Kyle Boatright
Atlanta, GA
2001 RV-6 N46KB
2019(?) RV-10
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