Quote:
On summits web site you can select coils by primary resistance. For example the Mallory 30451 "E" core coil has a primary resistance of 1.4 Ohms. I think that is close to combination of a stock coil primary resistance (around 0.7 Ohm) plus the ballast resistor (around 0.85 Ohm.)
In theory you are absolutely right, the ignition box would see the same.
But, in practice it might not work so well. The reason is the cranking power. Remember that with the ballast resistor in the system it's bypassed and the coil sees the full battery power.
Let's assume battery voltage is 11 Volts while cranking, let's see what the numbers say:
a) original system, ballast .7 Ohms, coil .7 Ohms.
Power to the coil (ballast bypassed) is 11*11/.7 = 173 Watts
b) no ballast, new 1.4 Ohm coil.
Power to the coil is 11*11/1.4 = 86 Watts.
Now you have only half the power to the coil while cranking! If you put half in on the primary, you will have half out from the secondary to the spark plugs!
Go with a complete system, an electronic unit + a coil that the vendor of the electronic unit is recommending.
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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