Question on ballast resistor

[spstan]

My limited understanding of a ballast resistor is that it reduces voltage across the 2 contacts and in the process produces heat. So I got a replacement resistor from Advanced Auto (Carquest brand) and used it for a while. Bought a NOS ballast resistor on EBay to replace it and noticed that the NOS resistor was a little thicker and a little longer than the Carquest resistor. I'm wondering if this small difference could effect performance. Paul

 

[65Port]

Unlikely I'd say without more info. When you say performance, what aspect are you referring to here- starting, idling, part-throttle or something else?

 

[spstan]

Unlikely I'd say without more info. When you say performance, what aspect are you referring to here- starting, idling, part-throttle or something else?

Starting mostly. Paul

 

[Big_John]

My limited understanding of a ballast resistor is that it reduces voltage across the 2 contacts and in the process produces heat. So I got a replacement resistor from Advanced Auto (Carquest brand) and used it for a while. Bought a NOS ballast resistor on EBay to replace it and noticed that the NOS resistor was a little thicker and a little longer than the Carquest resistor. I'm wondering if this small difference could effect performance. Paul

Short answer is no. As long as the resistance is the same, everything will perform the same. The new one was probably built to a cheaper price point and the NOS will be the one of choice only because it will probably handle the heat better and last longer. It does change that reduced current to heat and that is why it's a fairly robust ceramic housing.

 

[Big_John]

Starting mostly. Paul

Since the ballast resistor is NOT used in the starting circuit, it won't make any difference there.

Note that the start position uses the circuit marked 14-PK and the run circuit uses 16-RE. Twist the key to start and the ballast is bypassed, release to run position and now the ballast is in the circuit.

 

[spstan]

Thanks for diagram. very helpful. Paul

 

[Big_John]

Thanks for diagram. very helpful. Paul

I need to redraw it myself so it's clearer...

One of these days this winter... LOL.

 

[halifaxhops]

As long as it is rated the right ohms for your system it is fine. A ECU definitely have to be matched for best performance.