Originally Posted by flemsmith
I was looking at the Dyna III ignition module I bought some time ago, and it says it needs to work with coils that have at least 5 ohms primary resistance. I'm pretty partial to the ones I have already, and they're 3 ohms. Wonder if the output amps really can't drive 3 ohms? Since they sell what looks like the same unit for BMW's that are rated for 3 ohm, I'm wondering if they really have a weaker output drive, or just a more conservative instruction sheet? I'm almost inclined to try them anyway, and just not go far from home for the first 100 mi or so in case they go belly-up. But, on the other hand, I'll probably worry about them too much to relax. If anyone has real world knowledge, I'd be interested.
I am running 3 ohm coils with a Dyna III on my I-Convert and that set up is working very well for me over the past several thousand miles now. Have a read here, the instructions clearly state that 3 ohm coils are to be used:
That being said, the instructions from Dyna have been less than crystal clear over the years and there is some degree of confusion over what should be done. Personally, I stuck with 3 ohm coils (Pertronix flamethrowers) and the Dyna III. It has been working flawlessly for me. I did ground it as instructed - I believe that is key for longevity.