Unpotted GN Ignition Module

[John at J&S]

Kenny D. gave me a module a few years ago to play with. He wanted to see if I could "soup it up", to get more spark energy out of it.

For reference, I hooked my scope to the module while it was running on his dyno and sketched the relationship of the cam and crank sensor, and the EST signal.

I spent a couple weeks that winter playing archaeologist, dissolving and scraping, little by little.

It still works, and I was able to draw a pretty good schematic of it.


Remember, the energy stored in the coil increases with the square of the current. Going from seven to eight amps, the energy would increase by 31%.

Increasing the spark energy by lengthening the dwell won't do any good, since the module limits the coil current to about seven amps. A Boost-A-Spark might help at high RPM, if the current limit has not been achieved. Haven't tested it, though.

The current limit can be raised only by digging into the unit, and changing the current sense resistor. This would allow for higher energy, if the voltage is increased.

Here are a couple pics of the inside of the module.

 

[gnjones231]

Nice schematic...thanks! I've always wondered what was in there....


I built a prototype add on ignition quite a few years ago. This thing is designed to go between the ign module and the coil pack and operates in one of two modes (normal and high output/high rpm). The original breadboard design was tested with a .1" gap and 30 psi of boost. Worked great! Never missed a beat. The next version was put on a pc board in an attempt to get it in a useable package. The package isn't quite done yet, but I do have a picture of this unit if anyone wants to see it. Email me if you want it.

Now for some specs....the stock ignition can store 169mj and has a secondary ouput max of 32kv. It can maintain this to about 4000 rpm (give or take) and then starts to deliver less mj. The specs with my add on unit can store 576 mj and has a secondary output max of 96kv. It can maintain this level of energy to about 6600 rpm and starts to drop off after that. It will also produce 169mj at about 12,000 rpm.

What about the MSD dis4? Going from memory, it's an 80mj system.

As it stands, this unit is probably an overkill by a wide margin. I still have a lot of testing to do to figure out what is optimum.


Dave
gnjones231@mchsi.com