Originally Posted by crispeed

Due to the design of magnetic/reluctor triggers as rpm increases ignition timing will vary or retard. I'm not going to get into why that happens but do the research and you'll find out for yourself. Most modern ECU's have some type of system built in to remedy that problem. Both the E-8 and 11 ecu series got variable trigger angle vs rpm so basicaly you can eliminate that problem, The previous or earlier 6 series didn't. Timing would retard depending on application up to 10 deg at high rpm. That problem got even worse if gains were increased. Anything placed between the ECU and the coils would aid the problem even further.Everyone's favorite Knock retard and Ignition amplifier box would be prime examples. I've seen up to 10 deg of retard at high rpm. Now for the dangerous part about this whole ordeal would be by placing the metioned above units only on the leading side would result in even more leading ignition high rpm retard than on the trailing side and we all know what that leads to if you're trying to run zero or just a little ignition split again depending on the application, on a heavy load or boosted application. KABOOM!
This is the main reason why the earlier Haltech ecu's were known to fire the trail before the leading when the split got very close. This is not a problem with the latter series once igntion setup is done properly.
You must always verify ignition timing at varied rpm levels for both leading and trailing events.