we might need to in order to prove/disprove any theories. I have no intention of using the original ignition module. The ignition transistors only cost about $1.29 each last time I checked. Allows me to use any coil configuration I want. I am still undecided which coil setup I want, because I have been wrong before. I am only mildly curious as to what is on the eprom, so don't do it for me, do it only if you want to. It is still possible to figure out what they did without an eprom's data.
I wouldn't assume you can use any coil by simply driving it with a transistor. I'm pretty sure the GM ignition modules have current limiting, basically driving full-on until the current in the coil reaches the limit and then holding the limit.
Here's the coil schematic. Looks like it just needs a 5v signal
ls1_coil_schematic.gif
Not sure if you were talking to me or not. But I do know that the LS coils with the igniter built in are very basic. Hit one with a 5v signal and hold it. You will burn it out. Dwell time is controlled by the ECM. The pulsewidth of the 5v signal will prove it when you rev it up while watching it with an oscilloscope. It is not cost effective nor practical to install a dwell control circuit inside every coil. The size is a factor, not to mention temperature. More parts=more chances of failure. This is not a new concept for me at all. See it every day at work.
Now, you have to ask yourself.....do you want to pay $100 per coil or $45? Second, I will set up ion sense ignition feedback on mine, so I don't want any surprise circuitry in my way.
I have decided to use ordinary coils for mine, the rest can do as they will.
I'd pay about $25 for 8 from the junkyard assuming they'd work with the LT1 PCM. It's loaded with LS engines these days.
Sure, the LS coils are simple and the LS controls do dwell, but so what? The LT1 PCM isn't a LS PCM. I don't believe the LT1 ignition module is as basic. I have no idea if a LT1 PCM does any internal dwell timing or not but I doubt it. I expect the LT1 ignition module is a current limiting HEI type design. So, if you run the LT1/TBI etc coil on straight switched power you'll likely just burn it out.
Last edited by lionelhutz; 09-19-2017 at 02:18 AM.
I dont think we'll use an lt1 coil, i think the idea was to use the ls1 coil
I am not so sure the lt-1/vortec ignition module is auto dwell or not. Guess we'll find out. Not one of the most challenging problems ever, you know. You are putting cart before the horse. We need to get back to decoding and counting, otherwise we will get nowhere.
Here is a dwell calculator for you. Stretching the trigger signal from the ecm should pose no real problem.
http://www.useasydocs.com/theory/setdwell.htm
I will not discuss this any further until I need to. I have more important things to do. You have a better idea, draw it up and show us. That is why this forum exists. To share ideas and solve problems. Offer us something.
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