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Best EI setup for the money
I've been reading and talking to guys for a long time on this subject, and have gotten 50 different opinions. I understand the pro's/con's of the different variations (emag, pmag, lightspeed, slick, etc) but I can't come to any conclusion on how to setup the ignition based on the options or real data. Dual Pmags, one Pmag one slick, or one Pmag one Lightspeed are the three combos I've come down to...
Thoughts? |
Electroair
Don't forget to look at the Electroair EI. It has been around for a few years and just recently STC'd for numerous aircraft. I had Lightspeed on my previous RV and prefer the Electroair. Easy installation, very smooth, performs great, and no maintenance.
The problem you are probably finding is real performance gains are difficult to measure because most people have different engine configurations and have no baseline to compare an EI to dual mags or another EI since they have been flying only with the EI since day one. On my RV4 I added the Electoair after flying on dual Slick mags. I gained about .5 gph in hard flying and 1 gph in leaned cruise. The engine runs so much smoother that I can easily run 25deg LOP without detonation and pick up another .25 gph savings over leaned ROP cruise flight while only giving up around 10kts of airspeed. Although not easy to measure it was pretty obvious I picked up some HP as well. |
Jon Johanson's choice
A little while ago I spoke to Jon and he recommended
Lightspeed http://www.lsecorp.com/ But then again it is perhpas just one mans opinion like anyone of us. |
This is what I did. Not necessarily right :) Lightspeed on one side with a mag on the other.
Reasoning: Wanted to have the advantage of an electronic ignition system for timing advancement under various conditions. Wanted to have a magneto for it's decades of proven reliability. Additionally, if I'm away from home base and the EI dies, chances are I'm not going to be able to get it fixed however, you can get a magneto fixed almost anywhere. Hope this helps |
Look at this.
This new ignition system was shown here last year, built by another experimenter:
http://www.g3ignition.com/ I lost electrical power earlier this year and worried about my Lightspeed dying on me but the battery stayed up long enough. This G 3 system reverts back to a mag, should the electronics go TU. A good alternative, IMO. Best, |
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http://cafefoundation.org/v2/research_reports.php and read the very long reports on this subject. Maybe it will help to arrive at a decision. I concluded from the reports if you fly mostly below 10,000' mags work just fine. One CAFE comment indicated that up to 8500' mags may be better. Anyway, I've been with EI (Jeff Rose Electroair) and liked it. But that was with the Cozy MKVI where most flying was up around 12,000'. Oh yea, the engine does start quicker but it also kicks back on the starter gear once in a while necessitating a fly wheel change due to a broken cog. That happens when voltage drops to a point where EI looses its brain. A wire wound starter will go a long way to prevent this from happening. A very reliable electric system is also a must to keep the thing happy and the engine running on EI. Don't believe the fuel burn hype, the Lycoming engines need fuel to produce HP. EI may be a tiny bit more efficient but it isn't what is claimed. For better or worse, EI also changes CHT and EGT temperatures from what you see with mags. Some believe EGT's are too hot causing early exhaust system failures. The jury is also out on what running at 30-36 degrees advance does to the valves, the Lycoming system was designed to run at 24-25 advance. I'm on 2 Slicks for now and doing just fine. If one quits, I may go to one of the EI systems. They all work but I am partial to Electroair. |
It is necessary to advance the timing when running less than maximum MAP, due to throttle retard or higher altitude, since the amount of A-F charge in the cylinder is lower and takes longer to burn. The optimum ignition timing is when the peak pressure occurs at about 15? ATDC, so to get this you must ignite at earlier and earlier degrees as the charge decreases. That is why an EI will give more power and lower fuel burn. If you have fixed timing the peak pressure will take place much beyond the optimum giving more fuel burning as the valves open and higher CHTs and EGTs. Which do you think will be harder on the exhaust valves?
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Thomas S. AirVenture Presenter 07/26/11 http://www.eaaapps.org/presenterinfo.aspx?id=1470 |
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The Cafe Foundation articles David mentioned are very good but dated. Definitely worth the read. Also check out each of the EI's sites where they have a good amount of information on how their systems work. |
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