Quote: When the engine is running, you can get by fine with a lot less current at the points. That's the purpose of the ballast resistor. If the points were to receive full battery current/voltage at all times, they would only last a few hundred miles before needing replacement. On the same token with the electronic system it protects your coil from premature failure, unless your running aftermarket stuff such as MSD.
At the time of cranking (when the starter is operating), a separate wire gives the points the full 12 volts, bypassing the ballast resistor. When you release the key from "start" to "on", all the power to the points now has to flow through the ballast resistor, preserving the points.
For the .002 second performance gain, it's not worth running your coil at 12+ volts when it's designed for 9v. You wont wreck it right away, but you will shorten it's life.
One of the recent Mopar mags had a question about running a 12 volt coil w/o the resistor, the reply was that it would cook the ECU box. Why would that happen? I thought the resistor was to keep the coil from seeing the full voltage?
The car in question had an MSD coil designed to run on 12 volts.
