DIY LTCC or similar system for LT1s

[spfautsch]

Finding the biggest positive jump of about 16*. On high rpm converted to ms is not much and can be compensated. On very low rpm around 1000 it can be a little enough to be felt a bit, since it converts to something about 1.5ms reduction of dwell.

I'm thinking that instead of some table interpolation maybe a simple damping / smoothing function on the millseconds to degrees conversion would be better.

Now on the decel conditions, the issue seems to be fueling. The dfco have some spark blending recovery, so you don`t get a 40* jump but slightly increasing the advance in couple of jumps of 3-5*.

My morning test drive (haven't driven it in a month) seemed to agree. I have on occasion felt the fuel resume from DFCO present a bit of sluggishness. I do have some code in the profiling logic that can help determine whether it's missing a firing event or two in this scenario, but I'm not sure it's worth spending time on at this point in the project.

What do you suggest as the max on-off time in percent that will not decrement spark output. I am sure some visiual testing can be done on your rig, with different on-off settings for 5-10 minutes constant running.

I think 50% duty cycle is more than safe unless you're planning on trying to qualify for a NASCAR event where you're going to be running > 5000 rpm for several hours. But that's just my gut impression of how these coils work. A safer answer would be I don't have enough information to answer that question.

Not sure if you can make some DYI pressure chamber.

I'd love to build some more complete data for these coils, but I also have other projects I need to / would like to tackle. Fixing the rotten garage door trim, the bathroom windows, etc.

Anyway, I do have some good news. I just got back from the first of what I'm sure will be many test runs, and I think I reproduced your on/off issue with a hard WOT pull (no deceleration was involved). The issue continued on for a while just like you described. Felt more or less like a 2-step that had been left on after launch and was getting random, incorrect sensor data. At the first cross road I pulled off, shut it down and restarted, and the issue was no longer apparent. This tells me it's most likely some boneheaded picket-fence error (unchecked bounds) or something similar. I'll have to spend some time analyzing the logs, but it's probably something incredibly simple + stupid. That's not to say it won't be hard to find, but my fingers are crossed.

Also, I've been messing with fattening up the cranking dwell, and I think a 160 multiplier for the 100/200 rpm rows is already too much. Will post more observations after some experimentation.