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what is called a dwell duty map. I wont get into its exact function in this post, but it allows you to modify the coil charge time. The consequence? By raising the charge time of the coil, it produces a much hotter spark. In all of the programs I have looked at from various ECU reprogrammers, none of them have changed these values. I suspect they either simply dont know about it, dont know how the map works, or they just leave it up to you to upgrade the ignition system yourself, BUT, I have been playing around with it for the past two weeks on my own Z. Typically one needs to regap their plugs from the stock 0.044" gap (1.1mm) to about 0.035" in order to prevent misfire. This is simply because the additional air and fuel in the cylinder lower the coil's ability to throw a spark across the gap (the real explanation is quite lengthy so I'll leave it at that). When this happens, the air/fuel dont ignite and it misfires. So you shorten the gap and the spark will jump. By raising the charge time of the coil pack, when its field collapses, the larger flyback creates a much stronger pulse of energy which produces a stronger spark. I have regapped my plugs back to 0.044" and running 17psi of boost I get no misfire. This is with the platinum 6B series TT plugs - nothing special. This is because I have increased the charge time of the coil at these higher load values. The only drawback to doing this is that by increasing the charge time, it will make the coil get a little hotter, physically. This will tend to make the component fail earlier than it normally would, but Russell sells them for a dime a dozen. To me, its inconsequential. What this means is that although I am not flowing 600HP worth of air, if I choose to, I dont need some fancy ignition upgrade to keep it from misfiring. How long the coil's life will be shortened is probably a simple statistical calculation, if you raise the charge time by 10%, then I reckon it would shorten its life expectancy by 10%. MTBF gets into some strange logic so I wont go there, but I'm sure most will agree with my reasoning. Its nothing complicated to figure. But the ability to increase the power of the spark is right there in the ECU. All you gotta do it just increase the values of the map. This will be an option in my Zemulator setup - probably not right off the bat though as I still need to further test this for reliability, but I know it thoroughly works. :-) Maybe I should ask you the question your question begs to be asked: WHY do you think you need an ignition upgrade? If you aren't experiencing misfire with your upgrades, the gains of an ignition upgrade will be very marginal. (Note: a hotter spark is ALWAYS better than a cooler one as it ignites a larger core of air and fuel and consequently produces a more thorough burn. THIS is why there are *some* gains, but they again, are only marginal).
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[ agpowers@bellsouth.net ] [ Zemulator Information Sheet ] When pigs dance, you better get it on video... "You never really learn to swear until you learn to drive."
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