I like a friendly debate too. Your response raised a couple interesting questions about the Mopar ignitions.
The ballast resistor is the biggest factor that I'm unsure of here. It does seem like it would do more to limit current at low RPM than at high RPM, and an aftermarket coil could possibly heat it up more from more current draw, making the coil self-defeating until you bring the RPM up. Would it be more accurate to say the coil can't draw more current than the ballast resistor allows?
Well, according to ohms law a resistor will limit both current and voltage. I agree that there is a self defeating property built in to the mopar style ballast resistor. I have put a Blaster 2 on with a Mopar ecu and that ballast got way freaking hot, far too hot to touch in fact and of course the resistance increased.
It does seem a bit weird that the ignition would have an easier time lighting off the mixture at high RPM than at low RPM, but that often seems to be the case. With no ballast resistor and no dwell - just emptying a capacitor - the spark energy is the same across the rev range, or at least it should be.
Agreed. Something interesting I came across in an engineering study of the MSD 6AL2 is that they (MSD) calculates the spark energy in mj at 1500 rpm adding the energy of all the sparks vs just a single discharge. I'm guessing that all manufacturerers do the same. Seems a bit disingeniuos as high rpm spark is what we, as hot rodders, are most concerned with. I you are interested, PM me with your e-mail and I'll send you the .pdf It's too big too load up here.
My educated guess in regards to the CDI performing so much better in a high performance engine at high rpm lies with the ability to provide a major whack to primary coil without having to wait for the coil to saturate. At higher rpm the longer spark duration is not necessary due to the minimized time of the compression cycle. I also believe that that "whack" can provide the coil with enough voltage to jump the gap at very high cylinder pressures where an inductive ignition just doesn't have the time to pull it off. Make sense?
It wouldn't surprise me if that was the case. Unless there's a thermal shut down or the ballast resistor puts an absolute limit on the current, most transistors can be damaged if you overheat them from too much current. Or, depending on the internal construction of the box, something else may get damaged - it's possible that some of the internal connections may be the limiting factor.