I would think the spark plug on the untested output terminal has deposits that are conducting to ground, thus increasing the output on the tested terminal. Or visa-versa, the low observed output terminals are low because their untested terminal twins have excessive resistance in wires or plugs, resulting in less voltage at the tested terminal.gltriker wrote:With recently installed, properly gapped (0.028") NGK DR8EIX spark plugs into very clean cylinder head threads and no anti seize or other dressing applied, why would the lower spark plug wire outlet, on both green 3ohm Dyna ignition coils, provide so much more delivered potential than their respective upper spark plug wire outlet can provide?
Here's a simpler way to look at it, and hopefully this will bring it home. I mentioned this in article probably two years ago. The dual output coil fires in a loop, a circle. The source is the center of the secondary winding, the loads are the two series-wired plugs, the return is to the center of the winding again. I have found that if you ground one of the terminals on a dual output coil, this concentrates all the electrical energy on the remaining terminal, increasing its voltage. I mentioned this before. One way to get instant high voltage ignition coils is to ground one of the twins. Of course now you need four coils instead of just two, and there are problems on the primary side, but electrically it works. I've done it. This weirdness explains what I said above about one output from a dual output coil having higher voltage if its twin has a spark plug that is bleeding voltage to ground. The very simplest explanation and one that fits the above is the untested plugs were not grounded to the same integrity as the tested ones.
It's reaching, but I can't see any other explanation, and this theory at least I have proven in operation.
So, no one is going to ask about the BMW special design?