MP chrome box w/.25 resistor

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Longgone

Longgone

John/68 Barracuda & Dart
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I`ve been using the MP chrome box w/ .25 ohm resistor and the unit works great if I don`t let it idle too long. If I have to let the car idle for tuning,etc.,for any length of time, it`ll simply cut off and not start again until the resistor cools or I swap it out. Has anybody else had this occur?
 
I did have this happen to me before, the only thing is I didn't measure the resistance of the resister as the third or forth time it burnt out. I replaced it and after that I had no problems.
I went into the garage tonight and measured the resistance of 3 different resisters I have and all were between .88 to 1.2 ohms. One from a new orange box kit (1.2), one old and one was still in the box of a brand new super coil (.96)
Hope this helps.
 
I have 2 resistors here and they both measure 1.2 ohms. Does the chrome box specifically call for a .25 ohm resistor?

BTW do I understand you correctly that after it idles too long and shuts down you can swap out the resistor and it will start again? If so that's the first I've heard of a Mopar resistor doing that unless it's a type of thermistor which I didn't think these are. Does that resistor get really hot?
 
The chrome box does call for a .25 resistor ( big honking thing) and it does get very hot if left idling too long. I have two resistors mounted to the firewall anyway because the .25 ohm resistor was too big to mount in the stock location, so I just installed it above the other. If I switch it over to the 1.12 , I can continue to work. I`m concerned I may burn it out (the .25) if I`m letting the car idle too long, but if I switch it over to the 1.12 am I going to burn out something else, like the box itself. Maybe that`s what MP referred to when they say (the chrome box set is) for race application only. I imagine there`s little if any resistance present at the resistor at WOT.
 
I won't swear to it but I wouldn't think you'd burn out the box if you run the 1.2 ohm resistor because your going up in resistance. The higher you go the more current is limited. It will probably decrease your spark output though since it's dropping the supply voltage/current to the box. The only thing is that 1.2 ohm resistor may run hotter than the .25 resistor because it will "absorb" more current and I'm sure it's power rating is smaller also. You can try it and see what happens but it may burn out.

I thought the orange and chrome boxes are both OK for the street. Only the gold box is for "Race only". Haven't read the ads for them in awhile but that's the way they used to be. Have they changed them?
 
I`ve seen the MP chrome box advertised as (race) and also without any specifics attached. I should clarify though that I haven`t seen it advertised as (race only) like the gold box. Larry we`re referring to the Mopar Performance chrome box which may differ from the Auto Zone box.(Sorenson) I have seen a Sorenson box that had the same # as the MP orange box, so they probably are the same box ,just a proprietary thing for MP. From what I`ve read is as your engine speed increases the ballast resistor allows more flow of electrons so that at WOT there is practically none. At idle is when the resistor works its hardest. The chrome box is supposed to rev higher without breaking up, but I wonder if the resistor they use with it, is why they often refer to it as a (race) box? With such low resistance it may allow too many electrons to flow at idle and thus only be suited for full throttle runs.
 

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