DIY LTCC or similar system for LT1s

[Tom B.]

The Delteq does use a Northstar module and coils.

[vilefly]

The Delteq does use a Northstar module and coils.

Then this information will be useful to you. It is northstar ignition system trigger wheel at the exact size and configuration for 10* btdc base timing.
https://www.thirdgen.org/forums/atta...thstar-dim.pdf


this is the northstar ignition system patent.

https://www.thirdgen.org/forums/atta...dis_patent.pdf

so, I think I was right in thinking they used an eprom as a custom signal generator that is synched and clocked to the optispark signal.
Easiest way I can think of to produce a complex waveform cheaply.

[Aroberson77]

Soic chip says HCF4050 31A317

[Aroberson77]

Found this pic of the LTCC that uses the LS coils

LTCC1.jpg

[Aroberson77]

More relavent reading. LT1 equipped boats used the Northstar ignition system

http://www.ls1lt1.com/forum/lt1-%7C-...ar-lt-1-a.html

[Aroberson77]

so, I think I was right in thinking they used an eprom as a custom signal generator that is synched and clocked to the optispark signal.
Easiest way I can think of to produce a complex waveform cheaply.

So does that mean we need to figure out what is on that eprom? I would almost rather use the LT1 ignition module and then use LS coils. I believe that is what your original plan was, right?

[vilefly]

So does that mean we need to figure out what is on that eprom? I would almost rather use the LT1 ignition module and then use LS coils. I believe that is what your original plan was, right?

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.

[Aroberson77]

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 forgot that you had found the transistor already...

[lionelhutz]

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.

[Aroberson77]

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

[vilefly]

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.

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.