I haven't been seeing much activity in the KR group lately so let me see if I can stir things up a bit? I have decided to replace my heads with new Rev049 dual plug heads and new cylinders and pistons. Not because anything is wrong with the ones I have, but because both quality and dual plugs give me reason to believe that I will be increasing safety as well as power. The obvious is a dual ignition system will give greater safety over a single ignition but, a two fire will also increase power. How much is part of the question I pose. A single mag puts out what? 10,000 volts and an Electronic ignition will put out 60,000 volts. In my big block stroker 496 my multi fire MSD box puts out 85 rapid fire ignition sparks verses the a single fire HEI. The results are substantial in power output. Im looking real hard at the SDS electronic ignition which will put out 50,000 volts and allows for timing advance that I believe is flat in a mag. This is important in power output and higher RPMs and I believe it is also important at varying altitudes.
Part of my thoughts and questions are around going full on dual electronic ignition with a battery backup or keeping the mag and adding the SDS ignition as a secondary. Having an electrical failure and thinking that a second battery to run the electronic ignition on a dual electronic is a question. Is it realistic to think you can have an electrical failure which in a totally electronic dual ignition would result in the motor stopping. Is it realistic to think you could react fast enough to flip on the backup battery while the prop is still spinning ? Where do most failures occur? Takeoff and landing. if your ignition fails in this conditions the prop will stop and you will possibly be going slow enough that you will not be able to get it to windmill to restart it after you turn on the backup battery ? I make this statement as a question. Is this most likely to be true ? Or, am I wrong? So, it gets back to what makes more sense. Two totally electronic ignitions or one electronic ignition and the magneto ? What is the effect of a fixed timing ignition in the case of a magneto and an electronic ignition that has the ability to advance as needed during different RPM settings ? I mean in a single electronic ignition in the same configuration with a magneto ? If I have not confused you yet, I think I have already confused myself in my ramblings. By the way. Does anyone know how much horsepower it takes to turn a magneto ? Makes me wonder how much power is being consumed by a magneto ? In our little planes and their low horsepower ranges, we need all we can get. If it takes 5 hp to spin a mag, it might make more sense to use a dual electronic ignition. On another note I am putting on a Revflow carb and I am going to add a wideband O2 sensor and digital Air Fuel gauge to set my A/F based on a 12 to 14 AF ratio in order to be sure to get peak power and proper mixture. The lack of science of setting the mixture based on a lean of peak idea is just way too archaic for me. But I will also watch temps too. Jeff York KR2
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