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Question about 1/2 and 1/2 EI/Mag setup

redhawk

Well Known Member
I am researching Electronic ignition for my O-320 on my RV3B, and the reason is I’ve read about how EI can make starting easier…
What if you have 1 impulse coupled mag and one E-mag(for example) ? Do you leave the E-mag powered during start? It seems if I do what I do now ( start on left impulse mag only) then replacing my right mag with EI won’t affect the start process if it’s not powered…
Cheers
 
Probably best to replace the impulse coupling with the EI, as the impulse coupling is a source of failure to get rid of.. but to answer your question, if you have the impulse and an EI, you’ll be able to start on both. Which EI are you thinking about?
 
EI/Mag

Hi Tom,
That makes total sense!
I’m thinking of the P-(E?) Mag. Sounds like the most straight forward install and really like that it’s self- powered. I did hear customer service not that great though…
 
Hi Tom,
That makes total sense!
I’m thinking of the P-(E?) Mag. Sounds like the most straight forward install and really like that it’s self- powered. I did hear customer service not that great though…
I can attest, customer service*and support has been super.
 
Works for Me

We have an RV-6, O-320 160 hp with a Lightspeed Plasma III on the right and a Slick with impulse coupling on the left. I left the Slick in the loop for starting. Immediate, near fool-proof starting is our favorite feature of this setup and it’s simple because there’s no need for backup alternators or batteries.
 
My -8A has a LSE Plasma II and a Slick mag with impulse coupling. I start with both ignitions on and it fires up on the second or third blade every time.
 
I, too can attest to EmagAir’s excellent customer service.
PMag on rt and impulse coupled mag on left. Start on both.
Tossing the impulse mag for 1 less failure point does have merit.
 
I like the EI on the left for engine start, because of impulse couplings issues/AD’s. If I was running two EI’s, I’d start on both (toggle switches). I currently have a SureFly on the left for engine start, and a non-impulse Slick on the right. Provides redundant ignition in the event of an electrical power generation failure. If my Slick fails on me, I’ll probably replace it with a P-Mag because it still gives me redundancy on that side. My SureFly is powered by a recharged backup battery that is always powered.
 
Ran EI + impulse mag for over 2000 hours on an O-320 with no issues.
Started using both.

The EI was the original ElectroAir ("Jeff Rose").
Finally replaced it with a P-MAG. No issues.

Currently dual P-MAGs. No support issues.
[Often times, stories of old support issues linger long past the point where the vendor has fixed the problems.]
 
Light speed and Slick Mag

If one were to have one electronic and conventional mag, wouldn't the spark advance be different between the upper and lower plugs?
 
Yes, most electronic ignitions advance the ignition, starting the advance at 24 inches of manifold pressure or less. The spark occurring progressively earlier as manifold pressure reduces by pilot throttle action or as a result of higher altitude.

The fact that the variable timing is much earlier than, the mag's fixed timing, causes no problems at all: the burning process, while the electronic mag is advanced, has already started before the mag fires the rest of the plugs. In this realm the mag's existence is merely as a safety back up; in case the electronic ignition fails.
 
At the risk of topic diversion, is there a benefit to running two EI’s over 1 mag and 1 EI source? My IO-320 has 1 mag on the left, 1 lightspeed on the other. When doing a runup I get no rpm drop when turn off the magneto. 75rpm drop when the lightspeed is switched off.
 
At the risk of topic diversion, is there a benefit to running two EI’s over 1 mag and 1 EI source? My IO-320 has 1 mag on the left, 1 lightspeed on the other. When doing a runup I get no rpm drop when turn off the magneto. 75rpm drop when the lightspeed is switched off.

That question requires a very nuanced answer. The short answer is: depends on whether the EI is "user configurable" and what type engine (assuming Lycoming, is it a PV or AV?).
 
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