Another Pertronix Question

How important is it to install the positive wire to the ballast resistor instead of to the postive post on the coil?

 

It looks like there is a wire already on the pos side of the coil, coming from the ballast resistor. That's what has me confused. My thought was if that wire is a 12V power source, there would be no need to run a wire all the way to the firwall just to access the factory ballast resistor. Any thoughts?

 

What does that mean for the Pertroix install? Is that the side of the ballast that I should connect to? Now I'm thoroughly confused... :? Patrick, how's yours hooked up?

 

Chris, the red wire (hot) from the pertronix has to get full battery voltage. The coil does not get a full 12v. You can hook the pertronix to any switched (hot w/ ignition on) source except at the coil. The ign. switch side of the ballast resistor is probably the easiest place.

 

Thanks William. I just finished the install and it fired first try! Right away I noticed a difference in starting and also a smoother idle. The backfire on decel is also gone. FWIW, I also replaced the coil and wires, but did not open the gap on the plugs (still at .035). Looking forward to a run to the beach today and also see if my MPG will change at all. Last tank was 16 MPG.

 

I thought we hammered this topic pretty good about a month ago, but. You mentioned that you replaced the coil. Some coils are internally resisted, some need an external resistor. The box the coil came in or the coil itself should say whether or not it needs an external resistor. If you are using the Petronix Flamethrower you should not use the ballast resistor on the firewall per the directions on the box.

 

Per the Flamethrower instruction sheet: "1.5 Ohm 4 and 6 cyl normal application...keep resistor in place. 3.0 Ohm 4 and 6 cyl normal application... remove resistor." There are other applications for both the 1.5 and 3.0 Ohm coils but they don't apply to my situation (8 cyl all applications, 4 and 6 cyl racing application, etc...) Since I'm using a 1.5 Ohm coil, I left the resistor in the system. Not really sure what would have happened if I removed the resistor, but it appears to be working as advertised in the current set-up. Time will tell...

 

I went looking for my instruction sheet, but looks like it hit the trash. What I recall was an instruction to test the voltage coming out of the resistor and if it was less than 12 volts, bypass it. Perhaps there is more than one Flamethrower coil available also. Mine says it has an internal resistor. It would seem that if you had an internal resistor dropping the voltage that has already been droppedby the firewall resistor you'll have low voltage at the coil.