Programmable Delco Ignition Module

[VL400]

There is an input that can be triggered by a flex output, its currently used for secondary rev limit. It could be re-purposed, but is on or off rather than variable/analog/PWM capture for what you would need.

Other issue is my module does not control spark advance at all (its left entirely to the delco except during cranking), so would need a fair bit of code changed to handle this.

[VL400]

Bit more has been happening with this, has been running my car for awhile on the latest hardware and has been perfect.

Finally got the code written for dwell control that can be independent of the ECU. The ECU still commands the spark advance from the falling EST pulse (so all your tuning is done in the ECU), but now the module has the ability to track a target dwell set by a 3D table (showed this a few months back)...

TargetDwell.png (71.03 KiB) Viewed 6908 times

And a screen cap from a running engine using LS1 coil dwell times...

Ign1.png (41.66 KiB) Viewed 6908 times

The top monitor, RPM in red and battery voltage in green. Bottom monitor has the EST dwell from the ECU in light blue (which is not being used in this mode), and then the red is a target dwell from the above table. Dark blue is what dwell actually got delivered. There will always be a little bit of jitter due to the module not knowing when the ECU is going to command the fire event (it changes with spark advance), I do however have velocity tracking code so under fast engine accel/decel the dwell is dynamically adjusted to try and match the target.

And some throttle, the light blue is from the ECU (which also has some dynamic dwell control) and what would normally get used...

Ign2.png (45.84 KiB) Viewed 6908 times

[Holden202T]

cool ever evolving

[VL400]

And a quick screen shot of dwell overlap working....

Overlap Rev.png (44.64 KiB) Viewed 6825 times

The top monitor in red is RPM, bottom monitor has light blue EST dwell from the ECU, orange target dwell from the above table, and dark blue actual delivered dwell.

This is a two coil setup on a V8, but on a single coil setup by around 3700RPM dwell starts to drop below what the LS1 coils need. This is simply due to enough time between spark events to fully charge the coil, and is why inductive multi coil setups are so common now - full spark energy at all RPMs.

The light blue EST output from the ECU shows this, as its a single output normally feeding a single coil (or a delco DIS, which does not overlap dwell) it needs to leave some time for the spark to happen while maintaining as much dwell as possible in the remaining time. Can see some of the small revs it drops below the LS1 dwell target.

On the big rev it would only be able to give 1.6ms of dwell instead of the 3.67ms that the LS1 coil needs (orange line). Now with dwell overlap the dark blue line can maintain full spark energy all the way to 6800RPM and more

[immortality]

Right. So I want to upgrade the ignition on the Senator and the standard route is MSD however another thread about capacitive discharge systems has me re-thinking and this setup sounds interesting indeed.

And just realised this is not what I was thinking

[VL400]

What were you wanting to do?

[immortality]

Just a simple ignition system upgrade on a Holden 304, It still has the original coil which is probably well past it's best so due for replacement and upgrade. I had intended to use an MSD 6 unit I have but reading the other thread about capacitive discharge units I'm having 2nd thoughts about it. I like the idea of the LS2 coils but reading back through the start of the thread I realise that this module doesn't seem compatible with the standard V8 304 ignition.

[VL400]

It is compatible with the dizzy in a holden V8 and you would no longer use the V8 ignition module and coil, but you are limited to running a single LS1 coil unless its a VT dizzy (can then run 8 LSx coils using only the dizzy for its hall trigger). Anything other than LS1 coils overheat in single coil setups as they are not rated to the duty cycle, would need to limit dwell significantly which really defeats the purpose of it. But they work great in multi coil setups. Can also fab up a crank trigger (few different patterns to choose from) instead of the dizzy and get more accurate spark delivery to go with it.

Lots has changed since the start of this thread, so there will be some very outdated information.

[immortality]

It's a VS unfortunately.

A crank trigger with multiple coils does sound interesting.

[VL400]

Its a limitation of the dizzy and no aftermarket ECU or ignition system can overcome it. There needs to be a way to signal TDC of a particular cyl or pair of cyl if you want to ditch the dizzy.

Can add a home signal that occurs once per rev or cycle, keeping the existing dizzy trigger and run multiple coils.