Ballast resistor for Chrome Box ignition

Posted By: roadhazard

Ballast resistor for Chrome Box ignition - 06/07/14 03:28 PM

What is the recommended ohm ballast resistor for the Chrome Box when using an Accell super stock coil?

I need a spare for a trip and would measure mine but my meter isn't cooperating and don't trust the reading.

Thanks for the assistance

Posted By: RapidRobert

Re: Ballast resistor for Chrome Box ignition - 06/07/14 04:05 PM

The nominal MP ballast ohms for the orange/chrome boxes is 1.25 ohms but that is with a chrysler coil. Accell told me to use .8 ohms with the super coil, the big yellow beast not the super stock round canister yellow coil you have and I ran it (the SC) 30 yrs ago with NO ballast & it never burned out. I think you could grab any ballasts you have laying around & they'd work fine. You have ALOT of leeway on how little ballast you can get by with and not burn out the coil and likely all of your spare ballasts will have plenty of resistance.

Posted By: Supercuda

Re: Ballast resistor for Chrome Box ignition - 06/07/14 04:07 PM

as Robert alluded too, ballast values depend on the coil not the ECU.

Posted By: mikemee1331

Re: Ballast resistor for Chrome Box ignition - 06/07/14 11:48 PM

agree with both. chrome box does not require a ballast but the coil might. 1.5 to .8 will work.

Posted By: 383man

Re: Ballast resistor for Chrome Box ignition - 06/08/14 05:11 AM

I been using a .8 ohm ballast with the Acell super coil and the orange MP box since 1997 and still going strong. Ron

Posted By: Den300

Re: Ballast resistor for Chrome Box ignition - 06/08/14 10:00 AM

MSD blaster II coil, chrome box, 0.25 ohm resistor. 8 years, never had a problem

Posted By: 1970A66

Re: Ballast resistor for Chrome Box ignition - 06/08/14 02:15 PM

Quote:

http://www.moparts.org/Tech/Archive/elec/4.html

Posted By: 65cuda

Re: Ballast resistor for Chrome Box ignition - 06/09/14 03:03 AM

I called MSD this week and ask them the same thing. got a new MSD coil cause my chrome Acell coil and chrome box got so hot I couldn't touch it. He said the MSD ss red plastic coil didn't need a resistor. even though the instructions said .8 ohm. so I left the .25 ohm one there.it got so hot I couldn't touch it either and quit. I think it burned out. so who knows what resistance is right.

Posted By: Supercuda

Re: Ballast resistor for Chrome Box ignition - 06/09/14 04:37 AM

You realize the function of a ballast resistor is to limit the current flow through the coil so it does not burn out. The lower the ballast resistance the more current flows thru the coil.

Posted By: Dunnuck Racing

Re: Ballast resistor for Chrome Box ignition - 06/09/14 05:14 AM

The .085 ohm piece that MSD sells works well with the Chrome box. But there is almost no noticeable difference in performance with a 1.4 ohm. In fact, the extra peace of mind far outweighs the slight gain I could measure. The MP boxes seem to live longer with either a high resistance coil or a coil/ resistor combination of 1.4 ohms or more.
Keith

Posted By: mikemee1331

Re: Ballast resistor for Chrome Box ignition - 06/09/14 12:56 PM

Quote:

You realize the function of a ballast resistor is to limit the current flow through the coil so it does not burn out. The lower the ballast resistance the more current flows thru the coil.

Posted By: RapidRobert

Re: Ballast resistor for Chrome Box ignition - 06/09/14 04:40 PM

If you have ~1.5 ohms total (coil+ballast) on an std ECU setup (not msd/not CD) then you'll be fine

Posted By: GomangoCuda

Re: Ballast resistor for Chrome Box ignition - 06/09/14 06:58 PM

Quote:

MP boxes seem to live longer with either a high resistance coil or a coil/ resistor combination of 1.4 ohms or more.

Quote:

If you have ~1.5 ohms total (coil+ballast) on an std ECU setup (not msd/not CD) then you'll be fine

Both good answers. People that say the resistor protects the coil are half right. It also protects the transistor on the ecu from overload. Obviously from this and many previous threads some people have successfully used much lower resistance without failure but not everyone will be that lucky. Years ago I played around with high tech heatsinks on the transistor(my cousin was making heatsinks for NASA). It was probably effective but not really worth the insignificant gain from running a lower ohm resistor than originally intended.

Posted By: roadhazard

Re: Ballast resistor for Chrome Box ignition - 06/09/14 08:38 PM

OK, well I finally have an OHM reading on my ballast resistor I can trust.

I've been running a 1.25 OHM and it has been working perfectly fine. I however tried another ballast that measures .6 OHM and it runs like garbage

So I'll go pick up a couple 1.25's and roll with it!

Thanks for all the responses

Posted By: RapidRobert

Re: Ballast resistor for Chrome Box ignition - 06/09/14 09:40 PM

Quote:

I however tried another ballast that measures .6 OHM and it runs like garbage

Yes that is real strange. that ain't makin sense that less ohms/more current to the coil is makin it run worse. Got another one you can try (in that range)?

Posted By: Supercuda

Re: Ballast resistor for Chrome Box ignition - 06/10/14 12:22 AM

More current means more heat. Had a Accel coil quit working when hot on me only to work fine when cooled off. Might be getting into thermal failure territory with the coil.

Posted By: 65cuda

Re: Ballast resistor for Chrome Box ignition - 06/16/14 07:28 PM

That's what I had a chrome round Accell coil with chrome box. Running the .25 resistor that came with the MP kit. coil got so hot it would burn you. quit on me. cooled down would start again. So I put on the MSD 8207 coil. it got so hot just running it to test in driveway it swelled up and split. put on second 8207 with the MSD .80 resistor. running in driveway again it got up to 220 degrees. ( reading with heat gun) afraid to drive it any where now. it might bust too. thinking about putting in a whole MSD system. only have 7.5 volts with fans on at coil. Talked to MSD they said the voltage is on target.