Will Bypassing Ballast Resistor damage stock ignition module?

[Scooter]

Hi all.. quick one. I noted a week or so ago that I had the same Petronix coil that the FBO ignition module kits come with.

Their kit bypasses the ballast resistor.

Put together a quick jumper and have been running straight 12v to the coil for probably a week now.

Just noticed this note on the Jegs website associated with the stock orange and blue ignition module:

Orange Ignition Control Unit 5,000 RPM
https://www.jegs.com/i/JEGS/555/40800/10002/-1?gclid=EAIaIQobChMI_cKlodzf6wIVeyCtBh0XMwcyEAQYBCABEgKKU_D_BwE

Use with ballast resister. Works with 2-Pin or 4-Pin ballast resistors. Use without ballast resistor will destroy the Ignition Control Unit.

I don't see how the lack of a ballast could damage the ECU.

The coil if it's not up for 12v.. sure... but the ECU?

The ECU gets 12v before the ballast in the circuit anyway right?

[Dakota]

This article says no to the ballast resistor if you don't have points.

https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/

[dodj]

Their kit bypasses the coil.

You sure about that?

[Jim AAR]

My Direct Connection instructions from the 80's say to use one, no mention at all of not using one. 

[Scooter]

Their kit bypasses the coil.

You sure about that?

Ok.. bypasses the resistor... kinda hard to get around having a coil in there somewhere. 

[Fastmark]

It depends entirely which ignition box you have. If you have the FBO unit or the Petronix unit, you bypass the ballast resistor with a jumper wire. Orange boxes must have it. I use the FBO system. They are much better and I like not using the resistor. They go out all the time.

[dodj]

Yes the ECU gets 12v, but that is for turning it on.
I've never really looked into it but......The ECU controls making and breaking the coil cct. The resistor is part of the coil cct. Stands to reason it will have an effect on the ECU switching transistor.

[Shane Kelley]

I ran a chrome box and a orange for a while without a resistor. I kept losing coils and I tried various brands. I put a resister back in the system and have been reliable for 2 years now. So my guess is that it's hard on the coil and not the box. 

[Burdar]

I'm pretty sure this is how it works.....The dual ballast resistors use one side to send reduced power to the coil.  The other side sends reduced power to the original "5" pin ECU.  The single ballasts are used with the "4" pin ECU.  The "4" pin ECUs take a full 12v and reduce it internally.  If you are running a "4" pin ECU and you are using a coil that is designed to take a full 12v, then you don't need to run a ballast.  Someone can correct me if I'm wrong.

[DeathProofCuda]

This article says no to the ballast resistor if you don't have points.

https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/

If this was true, why would the factory electronic ignition introduced in 1972 still use a ballast resistor?  If the factory used a ballast resistor with a stock style ECU, I would do the same. 

[Bullitt-]

 I believe Burdar has it right... OE 5-pin ECUs needed the ballast but the later 4-pin units are internally regulated as illustrated by the diagram below which shows the Blue wire going directly to the ECU.. This is the diagram from the electronic update kits which shipped with a single ballast.  Note the text at the top about not needing ballast for aftermarket coil.....

[Scooter]

This article says no to the ballast resistor if you don't have points.

https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/

If this was true, why would the factory electronic ignition introduced in 1972 still use a ballast resistor?  If the factory used a ballast resistor with a stock style ECU, I would do the same. 

I believe the ballast was there to protect the older oil filled coils from the full 12v... they simply could not handle it.

My 74 has the single ballast and a 4-pin chrome box, using the same Petronix coil the FBO kit comes with.

Based on info above and a few wiring diagrams I've reviewed,  I believe it's safe for 4-pin ECU to bypass the ballast as long as the coil is up to it.

Happy to be the crash test dummy here... if my ECU burns up I'll be sure to report back.

Thanks for the replies and info guys!

[DeathProofCuda]

Maybe I can't see the entire photo, but it looks to me like it says that you should use a ballast resistor that is recommended for your after-market or HP coil.

[Fern]

I have the FBO box and petronix coil. Been using it for about 2 years and have the ballast bypassed .
No problems yet.
I will add the 1st coil only lasted a week, but it was said to be defective, who knows. But like I said 2 years, no problems.

[GrandpaKevin]

I have the FBO box and petronix coil. Been using it for about 2 years and have the ballast bypassed .
No problems yet.
I will add the 1st coil only lasted a week, but it was said to be defective, who knows. But like I said 2 years, no problems.

3 years plus running the FBO box, coil and custom curved distributor on the wife's car.
No issues but I believe the FBO box is designed to bypass the ballast.

My 20 plus year old chrome box ECU, coil, ballast and MP distributor are also running perfectly on my Challenger. I have thought of changing out the chrome box and bypassing the ballast but if it ain't broke.....