MSD Ignition Systems
Discussion
Ive come across the theory that multiple sparks are a bad idea. You need one point of ignition, and then the flamefront should move uniformly across the compressed mixture, burning it all the fuel as it goes and producing maximum power. If you have secondary sparks, this starts secondry flame fronts that dissrupt the intial burn. I think additional sparks could possibly help if the combustion chamber was such a poor design that the flame front goes out, leaving unburnt fuel. Ask your self the question, why has this ignition system type not been used by motor manufacturers if its that good ? I would not believe a word unless someone can show me a significant power gain over a new standard system (with decent low resistance HT leads). I doubt it somehow....
blitzracing said:
Ive come across the theory that multiple sparks are a bad idea. You need one point of ignition, and then the flamefront should move uniformly across the compressed mixture, burning it all the fuel as it goes and producing maximum power. If you have secondary sparks, this starts secondry flame fronts that dissrupt the intial burn. I think additional sparks could possibly help if the combustion chamber was such a poor design that the flame front goes out, leaving unburnt fuel. Ask your self the question, why has this ignition system type not been used by motor manufacturers if its that good ? I would not believe a word unless someone can show me a significant power gain over a new standard system (with decent low resistance HT leads). I doubt it somehow....
Hi there,
Ford EDIS system used multiple sparks and it work really well for them, the main advantage of the MSD is the fact the plug gap can be increased as the voltage from the HT coil is soo much larger, without increasing the gap you wont benifit from it that much. I had an MSD and I noticed a conciderable difference in the mid range. I now have a wasted spark setup which is obviously a lot better than MSD as it doesnt use a coil that fires 4 times per engine revolution,
Phil
That I can understand, much the same as fitting a coil with a higher secondry voltage without all the added complexity of a CDI ignition system with multiple sparks. I thought the CDI type systems had all but died out, as what you gain in EHT voltage you loose in spark duration anyway, unless you have difficulty in igniting the mixture in the first place (ie two stokes, very high compressions or specialist fuels) . If you simply want a higher secondary voltage, the HT coil needs more turns on the secondary windings, or lower resistance windings (IE thicker wire) in the primary so the coil can draw more current and create a stronger magnetic field around the secondry windings (like a flamethrower coil - BUT NOT RECOMENDED for the RV8). A standard coil however can produce plently of EHT, but is frequently dumbed down by high resistance plug leads and resistive plugs, purely to stop the HT leads acting as radio transmitters, and various back emf's created in the coil primary glitching the cars electronics. Hence a cheap and effective upgrade of low resistance leads with interferance shielding, and if your (NGK) plugs have an "R" in the part number throw them away and get the same but without the R. I did various tests with copper HT leads, fantastic sparks, but destroyed two rev limiters in the process due to the higher back emfs in the coils primary.
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