Re: How low can I safely set "Max spark duration"?
Posted: Fri Aug 25, 2006 1:37 pm
The only risk of running too low of a max spark duration is that if it gets too low it won't light the mixture, so you dump raw gas in the exhaust and maybe light that off. Assuming you have a V8 Ford, the time between cylinder firings at 6000 rpm (= 400 cylinder events per second) is 2.5 ms. Your dwell + spark has to fit in that interval. Doesn't matter whether its points or MS II the most you can get is say 2 ms of dwell and say .5 ms of spark. If you set set max dwell to 4 ms and max spark to 1 ms, then at 6000 rpm you will get 2 ms dwell and .5 ms discharge. If you got to 5000 with 4 ms and 1.5 ms, then at 6000 you would have 1.8 ms dwell and .7ms spark. So try the 4 and 1 setting and if it gets better reduce the spark duration a little more in .1 ms increments.