CDI box (IC IGNITOR) 550 ltd

supergenius74 wrote:

maybe i will give that one a try, does it work with aftermarket coils? i have dyna coils 1.5 ohm.

My HEI design is meant to be used with 2.5-ohm coils or higher. It should work with the 1.5-ohm coils, but the HEI modules will get significantly warmer, so a really good heatsink will be necessary and it should placed where it can get a little cooling air. Or you could put a big 1-ohm, 50 W resistor in series with each coil, but the resistors will get hot.

Just curious, why are you using 1.5-ohm coils? The stock ones should have been roughly 2.5-ohm. New 2.5-ohm or 3-ohm coils would have been the preferred choice to prevent damaging the ignitor. It doesn't sound like much but 1 ohm difference does put a lot more current through the igniter.

But right now, if you haven't doen so, you should still make sure you have the right voltages at the coils and ignitor to make sure it's the ignitor that's dead. Red/yellow should have battery voltage on both the coils and the ignitor, and black/yellow on the ignitor should have zero volts. This should be verified with the ignition turned on, and even better, while the bike is actually cranking. Also with the bike turned off, the black/yellow should have close to zero ohms to the battery's negative terminal.

You would be correct. Thanks for designing that by the way. Its the best thing I have done to my bike so far.

i will try all of those things, maybe these 1.5 ohm coils are what killed my ignitor? I got them from dynatek and its what they said would work but they also said they should be within 10% of the original coils, i guess we had our ohms mixed up. So the factory coils are 2.5 ohm and i have 1.5 ohm coils, so i have to go with your design or i will always fry ignitors from now on. I will try yours and like you said i will make a hell of a cooling heatsink, i've to the perfect one in mind. -shane

hey would like to get some more information on how to make this ignition my bike is down and can't find any ignition

HEI modules often no longer use the MC3334 control chip so they no longer behave the same way as the original GM HEI modules. You might still find older ones or if you're lucky you might find some that still use that chip.

This page will show you haow to tell which type of HEI module you have.
s3.amazonaws.com/gpzweb/Ignition/HeiModules/HeiModules.html

THis page tells how to build the igniter.
s3.amazonaws.com/gpzweb/Ignition/GPZgmHEImod.html

This link shows how to make a module from scratch parts, but it uses a lot more parts.
s3.amazonaws.com/gpzweb/Ignition/GPZignitionMod.html

Hey are these still around ? Could you please put me in touch with somewhere j could get one ? Cheers
Thank you for your time