electrical and ignition Coil Drama...Black? Red? Aftermarket?

[jrhone]

So I have a 76 and a black coil with pertronix in a Tii distributor. I also have a Weber 38/38 carb, Ireland headers and a 292 cam. It runs pretty good despite the bottom end needing a refresh (rings). I though I'd get rid of that old dingy black coil and put a nice shiny new one in as well as clean up the wiring a bit. I went with a Pertronix Flamethrower 3 Ohm coil and installed it removing the resistor. I didn't bypass the starter relay, I took the resistor wire out and replaced it with standard copper wire. I figured that was easier because I could go back to the old coil by simply putting the resistor wire back in. The car idled smoother but lost a bit of power. I thought it would feel better since it should be an upgrade. The low end seemed a little lacking and the midrange power was lacking. Felt sluggish. The flamethrower is rated at 40000 volts and the stock black coil is 27000. So I put the stock coil and resistor wire back in and it's back to feeling normal. Should I look into the Bosch red coil? is it a bad Pertronix coil? I measured the resistance and got various readings but never anything close to 3 Ohms. More like 1.8 I think which is what the black coil was also reading. I'm thinking of maybe just going to a red coil and msd box. Tried and true and probably the best of that technology without spending huge money on an a modern ignition system. Thoughts? Can I use the red coil without the resistor with Pertronix igniter? Am I doing all this for something I won't notice?

[Buckeye]

Red coil requires 1.8 ohms resistor. Why don't you go with blue coil

['76mintgrün'02]

I though I'd get rid of that old dingy black coil and put a nice shiny new one

 

 

paint is cheap.

make your old one shiny!  

[m-tuner]

the best set up is a 6al. blaster coil. tack adapter, silicon wires secondary off 535/635 motronic, denso iridium fine wire gaped at 35-45 that will ignite any thing you thow at it, msd is on every aa fuel funny car built, it works with stock tii distributor,    Bruce M-tuner

[M3M3]

http://www.bmw2002faq.com/articles.html/_/technical-articles/electrical-and-ignition/ignition-coil-myths-busted-r52

[jrhone]

Red coil requires 1.8 ohms resistor. Why don't you go with blue coil

 

I thought thats only with points...with a Pertronix I thought you could run red coil with no resistor.... No?

[Buckeye]

I run contact breaker points and don't know much about Pertronix, but my recent experience and learning from members here I learned resistance between coil (+) and (-) plus resistor should be about 3 ohms. Therefore red coil sticker saying"use with 1.8 ohm resistor" means to me that coil post resistant is 1.2 ohms. looking at Pertronix website, their coil resistance shoul be 3 ohms (w/o external resistor) and that why I suggested bosch blue coil, because as you know the blue coil has internal resistor, which will give reading of about 3 ohms at coil posts. Have you tried callingPertronix askingthem why you cannot get 3 ohms reading from their coil as they claim on their website?

[M3M3]

http://www.bmw2002faq.com/articles.html/_/technical-articles/electrical-and-ignition/ignition-coil-myths-busted-r52

[Stevenc22]

I thought thats only with points...with a Pertronix I thought you could run red coil with no resistor.... No?

 

 

It doesnt matter whether you run points or petronix, the entire system should have 3 ohms of resistance. That means either a black or red coil with an external resistor or a blue coil with no external resistor.

 

You said you removed and then re-installed the resistor wire. Are you sure it is a resistor wire? Was it a horrible yellowish melted wire? Did you measure the resistance of the wire? Is it possible the previous owner replaced the resistance wire with with a ballast resistor somewhere in the circuit you don't know about?

 

Definately find out why the petronix coil doesnt measure 3 ohms. It should. If it doesnt maybe they sent you one of their 1.5 ohm coils by mistake!

[JohnS]

This is how you should wire up a Pertronix when using the red coil.  The + wire for the Pertronix comes before the resistor so that it gets full voltage.  Not the stepped down voltage after the resistor.  The combination of the coils resistance and any ballast resistor added on needs to be around 3 ohms I think.  Otherwise I guess you can fry the Pertronix unit.  The 1.8 ohm external resistor is what the red coil requires because the red coil is designed to run continuously with only around 10 volts.  It's boosted (resistor is bypassed)  using 12 volts for a short period of time when starting.  The idea, easier starting.

Edited June 26, 2015 by JohnS

[Slavs]

Watch our for the so called "Upgrades".

The BMW Bosch stock coils are excellent !

 

Slavs

[jrhone]

I'm just going to paint my stock black coil red and clean it up...lol...my black coil is back in and the car runs great. 

[JohnS]

Watch our for the so called "Upgrades".

The BMW Bosch stock coils are excellent !

 

Slavs

I agree 100%  The original German made ones seem to last forever.  On a nicely tuned car, I doubt you could find a noticeable difference between any of the bosch coils (blue, black or red) when they are hooked up as designed.

[JohnS]

I'm just going to paint my stock black coil red and clean it up...lol...my black coil is back in and the car runs great. 

Good move on keeping the stock coil.  Keep it black or else the originality police might come after you ...

 

"Coil upgrades == snake oil" Carl Nelson 1980-something

Edited June 27, 2015 by JohnS