My PMag RV-7A compared to one with mags
My two cents...
I've always had dual PMags on my RV-7A. I went up with a friend of mine several months ago. His airplane is basically the same, with the same engine but dual mags. We were working on running lean of peak. He was initially leaning too quickly and wasn't able to get lean before it got rough. I had him lean MUCH slower. He was able to get just lean at a low power setting without getting rough. On my engine, I can lean it until all cylinders quit working at the same time (at 150-200 LOP). You won't want to run that lean because you lose too much speed, but the combination of spark advance and much higher voltage of EI allow the plugs to fire with a leaner mixture. This gives reduced fuel burn. LOP ops give up a small amount of speed for a large decrease in fuel burn. I don't have fuel flow, but I give up about 10 knots for 3 gal/hour (based on lots of 2 hour flights and a fillup after landing).
I'm sold on the combo of electronic ignition and LOP operations.
I have a CS prop, so no RPM change...
Hope that helps.
Seb Trost
RV-7A
Boulder City, NV