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Mixing Electronic Ignition Systems

Warbirdsolutions

Active Member
Hey folks,
Anybody have experience using 2 types of electronic ignitions on the same engine? I have a LyCon IO-360EXP engine running a LightSpeed Hall effect ignition on the right and a Slick Mag on the left. I am considering using an EMag (PMag) on the left. I am concerned the 2 units may conflict due to mismatched timing curves. Obviously I could just run a 2nd LS ignition but that requires a back up battery that I would rather not have to install and wire. I was hoping that someone might have tried this with positive results. I did not ask Klaus for obvious reasons and the EMag guys thought it would be ok.
Thanks in advance!
Brad
 
I know of an RV-8 running a Lightspeed on one side and a pMag on the other for a few years now. No issues. One of his Lightspeeds died and he replaced it with a pMag.

Carl
 
From an engine performance standpoint there are only two things to consider:

- Spark energy available to light off the mixture when high and lean;

- Timing adjustability to ensure peak cylinder pressure at the optimal crank angle.

It appears that all the available electronic ignitions will cover the first requirement, but only one will completely cover the second as well. If the other EI manufacturers offered the full range of curve that's required to optimize the PCP/crank angle then I dont think that the engine would care what sticker was on the outside of the ignition box.

If you really want to achieve the best performance while having a "mix" using the products available today, then stick with a magneto on one side and use a SDS CPI or EM-5 on the other.
 
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I've run a few different combinations all with excellent results.

Lightspeed/mag
Lightspeed/Lightspeed.
Lightspeed/Pmag
Electroair/Pmag

Next up is probably CPS with Electroair.
 
Interested in comparison

I've run a few different combinations all with excellent results.

Lightspeed/mag
Lightspeed/Lightspeed.
Lightspeed/Pmag
Electroair/Pmag

Next up is probably CPS with Electroair.

Hi Walt
Peter here with a RV 6 io360 LIGHTSPEED and slick
I can see the obvious differences when I?m running the Slick versus the lightspeed ( big difference) on the ground and in-flight I?m curious to know what you saw when you ran LIGHTSPEED with P mag (speed, fuel flow, starting, EGT, Chy etc on one vs the other)

Thanks
 
P-Mag with ElectroAir ignitions

Our RV8 has an IO360 M1A with 9.0:1 pistons and an ElecrtoAir ignition on the right, and a P-mag on the left. The combination has been working very well. The engine originally had a Slick magneto on the left, which was replaced by the P-Mag after two magneto failures within 500 hours. We now have over 1000 hours flown with the P-Mag/ElectroAir combination.
With the 9.0:1 pistons, it took some experimentation to get the CHTs within the limits I like (no more than 380 degrees in climb, and 360 degrees ROP in cruise. LOP yields CHTs of 300 to 320 degrees at 34 degrees F and 13000? altitude.). Here is my setup:
P-Mag: The jumper is used to force the ?A? curve, and the setup timing at 2 degrees past top dead center yields a max advance of 32 degrees.
Electro Air: The base timing is set to 18 degrees using the potentiometer on the side of the control box, yielding a max timing of 32 degrees.
I hope that this is useful.
 
Mixing Ignition Systems

All, thanks for the input. Guess I'll pull my Slick off the left side and try the Pmag. I'll report how it does with the Lightspeed on the right.
Brad
 
All, thanks for the input. Guess I'll pull my Slick off the left side and try the Pmag. I'll report how it does with the Lightspeed on the right.
Brad

While I can't see a "compatability" issue, that's probably going the wrong direction from a overall PCP/timing issue. Both Pmag and Lightspeeds have an aggressive initial curve. Keeping the magneto helps to soften that issue by dragging the average timing down. I think Lightspeeds have a method to adjust timing, and the Pmags can be shifted somewhat, but you are certainly in for some significant fiddling/experimentation/flight test to find the optimal combination.
 
While I can't see a "compatability" issue, that's probably going the wrong direction from a overall PCP/timing issue. Both Pmag and Lightspeeds have an aggressive initial curve. Keeping the magneto helps to soften that issue by dragging the average timing down. I think Lightspeeds have a method to adjust timing, and the Pmags can be shifted somewhat, but you are certainly in for some significant fiddling/experimentation/flight test to find the optimal combination.

I?ll have to disagree. The Lightspeed or the pMag timing will be the dominant condition. The mag is just along for the ride.

The pMag timing can be anything you want it to be. I offer that if most people start off with just following the install instructions and selecting the lower curve to start with they will be very happy with engine operation. If they want to experiment they can go from there.

Carl
800 hours with dual pMags and putting them on the RV-10 (next month?) and new RV-8 project.
 
I’ll have to disagree. The Lightspeed or the pMag timing will be the dominant condition. The mag is just along for the ride...

Not the complete answer. PCP timing is a result of a composite of existing spark timing. In simple terms, if two flame fronts are started at opposite sides of the piston at the same time (as with a matched dual system), then the flame front should meet in the middle and PCP is achieved in X time. Dump one of those plugs entirely and the flame front will travel twice the distance to get all the way across the piston. PCP will still be achieved, but the time required to reach peak will be increased. This resulting effective PCP timing will be retarded from the above example, and explains changes in EGT and engine performance when doing the "mag check". A similar condition exists when you have two plugs firing but at different timing. The advanced plug will start a front that starts making its way across the piston before the lagging plug, but there is a good chance that the two fronts will still meet somewhere on the piston. For the sake of simple argument, the lead flame front may meet the lagging front 75% across the piston (75/25), which will result in a PCP timing somewhat retarded from that seen with a matched dual, but still advanced from a single spark event. In other words, the magneto is not generally "along for the ride" - it's contributing something to the party.

That said, there are certain high and lean conditions where it's likely the electronic ignition is so advanced that it outpaces the contribution of the fixed magneto, but anything short of that, the mag is being seen in the composite. And on the flip side, the magneto timing at 100% power is most likely the leading actor, since (based upon my testing) its data plate setting is more advanced than the engine needs (for 100% power). I would expect a properly tuned EI/Mag combo to have the EI retarded several degrees compared to the mag. In this case, the EI would be retarded even more than in a dual system as an attempt to drag the composite timing lower to the optimum for PCP.

In summary, a completely adjustable EI is a simple thing when coupled with a fixed magneto. The test is straightforward, and the results predictable and repeatable. Mixing two "sort of" adjustable EI's gets much more complicated - particularly when neither of the subject EI's have the required range to begin with.
 
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