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P-MAG question

Larco

Larco

Well Known Member
Hi All, I just installed a P-Mag and flew with it this morning. I was very impressed with the results of the electronic ignition versus the magneto performance. 180/CS prop
My question is to those who have actually experimented with this senario, What gain did you notice after replacing the second magneto with electronic ignition? Would you do the dual conversion again or stick with one mag?Thanks, Larry
 
Love to hear input on that as well. I'm also running 2 Slicks and am looking ot move to at least one P-Mag.
 
The gains from the second are not as dramatic as what you saw from the first, but clearly, the ignition system is better overall for it.

One thing you often hear is the first unit provides 80% of the gains, while the second only provides you the final 20. I flew a mixed engine for quite a while and added the second Pmag simply because it clearly provides a better spark to the combustion chamber. The airplane is not instrumented well enough to see the added gains from the second unit however. The RV on the other hand, went from two Bendix mags to two PMags in one jump, so the performance gain was immediately noticeable.
 
It is difficult for me to answer this one because I never flew my RV with traditional mags. However, in watching the P-mags closely, I typically hear that you gain close to 1 GPH with a single EI and 1.5 with a second EI.

Search the forum, people have posted their numbers before.

Best of luck with your upgrade.

One piece of advice, make sure to ground your P-mag to an engine case bolt, not on the firewall.
 
Toolbuilder is correct. I had 2 slicks, then went to 1 pmag for a few months and finally switched to 2 Pmags. GRT for watching the results.

My advice would be go with 2 of the same. Either pmag or slicks. It won't save enough fuel to go from two perfictly running slicks to Pmags to make the cost worth it. But I did it anyway. :)

When you have 2 pmags, it will allow your engine run smoother and give you a lower idle RPM. For a fixed pitch prop, a low idle rpm can be great. You can slow down fast and drop like a rock if you need to.

So one pmag gives you the fuel savings, but 2 Pmags give you more fuel savings, smooth engine and the low idle.

Also, I received great customer service when one of my Pmags went south. #2 right mag would not spark (bad coil). Called on thanksgiving day and got a quick trouble shooting lesson. Had to send it in. And had it back in less than a week. No disruption to my flying.:)
 
My experience was similiar to the above experiences. I went from 155 KTAS at 2500 rpm and 9 gal/hr with Slick mags to 155 KTAS at 2500 rpm and 8 gal/hr with 2 P-Mags. This is a RV-9A with an O-360-A4M and fixed Sensenich 72x82 prop. Dan
 
One thing to mention, the great benefits from Pmags don't come completely free. It will increase your CHT's. But this can be worked out with some good baffling and good air flow.
 
Mike D said:
One thing to mention, the great benefits from Pmags don't come completely free. It will increase your CHT's. But this can be worked out with some good baffling and good air flow.
Click to expand...

True but your EGT's will go down as well. The reason is that with the P-mags (and most EI's) you burn more of the fuel-air charge in the cylinder and less flame goes out the exhaust.

Also, make sure you have the jumper in to force them to the "A" curve, which is closer to a standard magneto. That or you could buy one of our EICommanders to monitor and manage your P-mags.

Here are two screen shots of the unit. The first is the Timing Divergence Alarm screen. It displays the timing difference between the two P-mags (the big 2.0), the current advance on the left and right P-mags (the numbers below the chevrons), and the condition of your ignition harness and plugs (the four blue and white bar graphs on the right. Too low a number and there is a short / fouled plug and two high and you have a loose connection / broken wire. The white bar graphs represent the plugs in cylinders 1 & 2 and the blue 3 & 4, the two graphs on the left side of the scale are for the let P-mag and those on the right side of the scale for the right P-mag. Remember, the P-mag fires two plugs at a time, thus we can cover all eight plugs with four bar graphs.)
TDA%2520with%2520Advance.jpg


This shot shows the three static query screens. This is all the items the P-mags are capable of displaying. (The P-mags in this sample are on the "B" curve.)
Dual%2520Query.JPG


The unit does a LOT more but those are some of the basic functions. For more details, here is the manual.
 
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Mike D said:
One thing to mention, the great benefits from Pmags don't come completely free. It will increase your CHT's. But this can be worked out with some good baffling and good air flow.
Click to expand...

The higher CHT/lower EGT is indicative of more complete combustion. If you want to cool the fire down bit to match your previous value, then LOP does that nicely. You get the additional benefit of even lower fuel consumption.

It has been my experience that you can lean the engine to truly ridiculous levels. You can almost use the mixture as a throttle.
 
It has been my experience that you can lean the engine to truly ridiculous levels.
Click to expand...

I totally agree. On a recent cross country with my dual P-Mags, I cruised at 170 KTAS at 8,500 MSL, burning 7.8 GPH. If I hadn't recently calibrated (and confirmed) my fuel flow, I would not have believed it.
 
Some good info here

Larry,
You are getting some good data here. You can sum up my input by saying "+1"

I went from a Slick Mag and Jeff Rose EI to dual P-Mags, so I don't have the dual Slicks to single EI perspective, but I do have the single EI to dual EI. Going to dual P-Mags, I dropped about 1.2gph. Now before all the nah sayers cast doubt, let me caveat that with "at a price" as the drop in fuel flow was due to the ability to run really LOP. Lower fuel flows means slower airspeed. The further lean you go, the slower you go, so everything is with a price.

As for the increase in CHTs, I was able to get lower CHTs by switching to the B curve as I was able to lean further due to the increase in advance from 34-39 degrees. It is all in how you run your engine which curve works best for you.

One advantage not mentioned yet, is the starting ability of dual PMags. You will notice an easier time starting and will ignite mixtures the magneto with smaller gaped aviation plugs could not.

YMMV,

Dan
 
Juvat said:
Toobuilder said:
It has been my experience that you can lean the engine to truly ridiculous levels. You can almost use the mixture as a throttle.
Click to expand...
I totally agree. On a recent cross country with my dual P-Mags, I cruised at 170 KTAS at 8,500 MSL, burning 7.8 GPH. If I hadn't recently calibrated (and confirmed) my fuel flow, I would not have believed it.
Click to expand...
Same here and I have an O-360, not an IO-360. I typically cruise at 150 kts LOP while burning 7 GPH. Just stunning performance!
 
Thanks for all the reponses. I have experimented only a little so far and see about a 1 gallon an hour less fuel burn and some other improvements mentioned by some of you . I am convinced that adding the second P mag is the way to go. Should have done it sooner. 1000 hours times 6.00 dallors a gallon WOW. I can now run a little lean of peak and maintain the same IAS using less fuel. Balancing the injectors come next. :) Larry
 
I have had issues with my dual PMAGS, but as mentioned here, they are still worth it and I will install them on my future RV-8. Not to mention the great service provided. As you've seen in this thread they will pay for themselves before long especially as gas prices rise. One economic point NOT mentioned in this thread is the low priced auto plugs that do a fine job IMO. They are able to use a larger gap, making a larger spark. And at about $2 per plug they are cheap and easy to replace at annual.
 
P-Mag info?

For those who have recently installed dual P-Mags. Did you use the Non impulse gear supplied by P-Mag or original lycoming parts? I have just removed a set of slick mags on an 0-320 D3G but will need a "new" pair of gears for the dual P-Mags I intend to fit. Where is the best place to buy them? Has the initial problems with those supplied by P-Mag been resolved?
Thanks as always.
 
Wentworth or any aviation salvage

ratc said:
For those who have recently installed dual P-Mags. Did you use the Non impulse gear supplied by P-Mag or original lycoming parts? I have just removed a set of slick mags on an 0-320 D3G but will need a "new" pair of gears for the dual P-Mags I intend to fit. Where is the best place to buy them? Has the initial problems with those supplied by P-Mag been resolved?
Thanks as always.
Click to expand...

I talked to a couple of aviation salvage places at one of the shows and they both said that they had them available no problem... Later, I sent an emal to Wentworth and they gave a price of 95 or so just after I bought a reconditioned one from Emagair for 170.
 
??

Why wouldn't you take them off the mags you removed and use them? I'm about to put a second pmag on in place of the LH impulse and just figured I'd use that gear.
 
PaulR said:
Why wouldn't you take them off the mags you removed and use them? I'm about to put a second pmag on in place of the LH impulse and just figured I'd use that gear.
Click to expand...


The impulse mag gear is different than the non impulse gear.

You will need a non impulse gear and most likely shorter studs to make the swap.

Non Impulse:

AEL61163_n__48547.1359172081.800.800.jpg


Impuse:

-3289572211863230504.jpg
 
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Gears

Brian,
Then can the spare gear from the mag I took out of the right side be used on the left side when I remove the impulse mag and change the studs? Same gear configuration?

Thanks
 
PaulR said:
Brian,
Then can the spare gear from the mag I took out of the right side be used on the left side when I remove the impulse mag and change the studs? Same gear configuration?

Thanks
Click to expand...

Yes it it was a non-impuse mag. I did the same thing.
 
I intend selling both mags to fund the purchase and would have thought leaving them "complete" would be more attractive to a possible buyer.
I figure buying new for the P-Mags would be the way to go.
So, new lycoming, reconditioned or direct from P-Mag (emagair)?
Anymore thoughts?
 
Here's another thought: While the magnetos are an accessory, the drive gears are an "engine" part. You certainly see plenty of mags for sale with gears still attached, but it is not a faux pas to keep the gears with the engine.
 
Auto plugs. Addressing the first question, I switched one at a time. 1st P-Mag gave almost all the fuel savings, smoothness, easier starting, and allowed for slower idle (400 rpm.) Second gave a little fuel savings, but added speed that the first did not do. No data on CHTs, but EGTs dropped both times. CHTs were low and not a concern.

Bob
 
I plan on swapping one of my bendix mags for a pmag pretty soon. Which mag should I replace? Does it matter?
 
Did most of you guys do this pmag swap on your own ? I have asked around a bit locally and have trouble finding an A&P who has electronic ignition experience. I admittedly like my hand held when I am doing something like this
 
I dumped the impulse coupled mag first. I wanted the mechanical complexity and weight off my airplane as soon as possible. The only reason for the impulse mechanism is starting, and that is completely solved with the Pmag and the start retard function. Just my thought at the time.
 
erikpmort said:
Did most of you guys do this pmag swap on your own ? I have asked around a bit locally and have trouble finding an A&P who has electronic ignition experience. I admittedly like my hand held when I am doing something like this
Click to expand...

I'm an A&P, but the change is dirt simple... If you're not comfortable yourself, then one of your gear head buddies can help you through it. No need for an A&P if you can't find one.

I will add that some people like to really add complexity to the system in the form of discrete test switches, etc. but in reality, all you are doing is adding a single 12v power circuit to the ignition, and the test function can be with a CB or pulled fuse - the rest of the wiring will remain unchanged. (Disclaimer- you may need to switch some terminals on the back side of the key switch depending on your start retard configuration).
 
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plugs

I started using the PMags with the fine wire iridium aviation plug$$$$ because I had already paid for them. Emag's aviation plug connection seems like a workaround for those people who want to continue using aviation plugs. The ends of the wires at the nut end get twisted terribly, to the point of shearing the insulation. I had a misfire that I traced to the insulation being sheared and all of the plug wires had been subjected to the same twisting. Yes, I used Silicone Lubricant, both spray on and DC4, trying to get the nut to turn easily on the silicone insulation with the silicone washers/glands.

I finally bit the bullet and ordered a new harnes (didn't trust the old one any more) and automotive plugs. MUCH better:D

I love the PMags and the auto plugs option. Just follow the instructions on installation of the plug in the adapter and then the assembly into the spark plug hole. Push on the connector until you feel a click and you're done. I had initially worried about it not being a screw-on connector...I shouldn't have worried: there's NO WAY that boot is coming off without you working at getting it off.
 
erikpmort said:
Did most of you guys do this pmag swap on your own ? I have asked around a bit locally and have trouble finding an A&P who has electronic ignition experience. I admittedly like my hand held when I am doing something like this
Click to expand...

Here's a way to tell...If you are capable of hanging and wiring a ceiling fan in a room that has no power to a box in the ceiling. You can install and time your own Pmag, yes it's that simple.;) and you dont need a ladder:D
 
Just some thoughts on Pmags with auto plugs.
First instillation is easy, as usual just read and follow the directions.
2. After about 50 hours I developed a miss. Replaced the auto plugs and it went away for another 10 hours. Not a pmag issue. The problem was the automotive spark plug caps were backing off. I solved this by using dielectric grease (can get from an auto store or ACS) and then putting a plastic cable tie on the boot.
Hope this helps someone as it took me a bit of head scratching to figure out.
 
NGK BR8ES SOLID

NGK makes a solid copper tip so it can't unscrew.Its called BR8ES SOLID,
Part# 3961
 
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