Ballast Resistor

[Harts56]

   I have a 70 Challenger 440 with Chrysler electronic ignition.  It was already in the car when I bought it.  Car runs well.  This week I had to replace my coil and I actually read the instructions and now have this question:
Coil is Petronix Flame Thrower 1.5 ohm 45K volts.  The instructions say to remove the ballast resistor.  Why?  Will it hurt anything?  If I pull the ballast resister out of the circuit do I just connect the wires together that currently run to it?  The car is a street car, max RPM's are 5500 to 6000.

Anyone out there who can educate me?

Thanks,

John

[MEK-Dangerfield]

John,

  I'm not up to speed on Pertronix coils, but my guess is that 1.5 OHM rating includes a built in ballast resistor. That way the coil won't see the full 12 volts.
Yes, you can just connect the two wires together after you remove the ballast resistor.


  Mike

[Chryco Psycho]

the 1.5 Ohm is the drop needed to the coil typically , so I think you stillneed the ballast , what Exactly do the instructions say about removing the ballast , most coils do not have a built in resister ?

[Harts56]

Mistake on the coil, it is a Flamethrower 40K petronix part # 40111

Instruction are very generic.  Shows this coil has a 1.5 Ohm drop.  I measured the following:
1. Battery voltage with key off, 12.92 V
2. Measured at coil with ignition energized (engine off) 4.7V
3. Jumped ballast resistor and measured at coil again 6.63V

Voltage seems to be low, but I do not see any other ballast resistor or anything else to reduce voltage.  All wiring is wrapped so I am unable to see if there is something "inline" with the wiring. 

Wiring looks like from the ballast resistor it also goes to the electronic ignition control unit, if I disconnect this I do not want to fry the ECU.

I guess at this point I nee to know what the voltage should be at the coil?.  Any ideas?

[Chryco Psycho]

typically around 8V measure it running though

[Harts56]

  With engine running 4.8-5.0 volts. 

[MEK-Dangerfield]

With engine running 4.8-5.0 volts. 

What side of the coil are you getting these measurements from? It sounds like the negative side, which would make these correct. 



   Mike

[Aussie Challenger]

  Some of the later hi energy coils require 12 volts, if you are running with that lower voltage it could be that your coil is shorting out internally, disconnect the neg. side and see if the voltage goes up, it should if there is no short.

[iron6]

I didn't see an answer to this question.  Do you disconnect the ballast resistor when using a flame thrower coil?

[Chryco Psycho]

the flamethrower should use a ballast

[ted]

havent used one with that coil, almost 20k miles, no problems.