Which ECU?

[UKcuda]

Obviously with the lower primary resistance the FBO coil will work better. More current in, more current out. But will the HEI stop it getting too hot if I used it without the resistor I wonder?

That's exactly what the HEI is intended to do.  I'm using a 0.7 ohm coil with no ballast.  Nothing even seems to be getting warm.  As I think I said in that other thread, people have had some of the best results using the Ford TFI coils which are very low impedence.

It would be interesting to put an ammeter in circuit and see what current is there with ign on and engine stopped - it should be next to nothing - maybe I'll try that at the weekend.

[UKcuda]

QQQ - seems a bit odd you have the FBO coil at 0.8 ohms that came with a 1.7 ohm ballast.  The coil would only be seeing about 4 volts, although I guess it's still pulling 5 Amps.

[ShelbyDogg]

If I fit the HEI module my only concern is the coil. Use a ballast resistor or not? But will the HEI stop it getting too hot if I used it without the resistor I wonder?

I use the GM 8-pin HEI units for my Fuel injection projects. Inside, 4 wires go to the regular 5 pin connector for the coil and pickup.



You can mount your 4-pin module like I did or screwed to the bottom of the dizzy to hide it. Just make sure that it stays cool.  For the ballast resistor, you can get rid of it. Make sure that you have a hot wire for "start" and "run" running to the module.

[Roppa440]

Found this handy diagram in my old Jacobs Electronics book.

[ShelbyDogg]

Just so everybody knows,  #5 "switcher" means COIL- and tach"

[72rtchallenger]

Hi Dave (and everyone as I've been "off-line" for a while)

I can totally recommend the HEI conversion I did as a brilliant alternative to the branded or OEM set ups.  It gives a hell of a spark and I've been using my 'cuda as my daily right through the winter and it has not missed a beat

Here's the thread:

http://www.cuda-challenger.com/cc/index.php?topic=62561

I use the HEI and love it,,would strongly recommend 

[Chryco Psycho]

I have always found the GM to be basically unstable over 5000 rpm , is the module causing ti or do your engines rev to 6000 with no issue using the GM module ?

[72rtchallenger]

I have always found the GM to be basically unstable over 5000 rpm , is the module causing ti or do your engines rev to 6000 with no issue using the GM module ?

so far I have had no issues

[Roppa440]

The aftermarket versions of the module are good to 7500rpm.

I keep changing my mind about fitting it as the FBO unit is working OK at the minute. Still not convinced it wasn't something going on with the ballast resistor either. But unless it goes off again I can't trace it. I need good weather so I can get the car out and really shake it down.

[UKcuda]

I have always found the GM to be basically unstable over 5000 rpm , is the module causing ti or do your engines rev to 6000 with no issue using the GM module ?

I've seen it written that some are better than others.  Mine is a Mallory chip and it seems fine but I've hardly taken it over 5K anyway.

I don't know what the cheaper ones are like; I may have paid an extra $8 just for the Mallory sticker.

[500Stroker]

If you are using an FBO coil don't rule that out.  Last summer I had intermittent problems with hot no start and hot while on the highway engine just dying.  Finally swapped out the coil last and problem solved.  I also have had 2 FBO boxes crap out.