Engine Idle Droop (supercharged)
 

Hey, looking for solutions to try and solve this dreaded stalling/droop issue I've been having.
Running a JRSC M45 supercharger, with lightweight alternator pulley, water pump pulley, and lightened flywheel (all of which are likely causing my issue....). Megasquirt DIYPNP2.

Essentially, the RPMs drop so fast it basically blows past where my CL idle should "take over", and either stalls or barely comes back to life
The issue is much more noticeable when hot, the engine will drop down to ~300 rpm or just stall whenever I'm coming to a stop & clutch in. It can also be observed just free revving in neutral (which is where I've been trying to tweak things in my driveway). It does seem to recover a bit better just free revving, not sure why being in motion would change anything. When warming up/ "cold" it catches itself much sooner and doesn't dip down sub 700 rpm.

I've been trying to research all sorts of things and play with timing / fueling, but I'm stumped.
Also I've noticed my MAP is a tad high at idle... I've checked with a vacuum gauge and it holds steady on the lowest part of the green range.. also cannot find a vacuum leak, so not sure what that's about.

I attached a cold start that features driving.. as it gets warmer it's more clear to see the RPM droops.
The warm start log also has driving, but shows the bounciness upon a warm start.
The "moreidle" log is me trying to play with fuel/spark settings and seeing how it catches the RPM.. not much success but highlights the droop issue.
Pictures below of the setup.
Really appreciate any input/changes I should try.

https://cimg0.ibsrv.net/gimg/www.mia...aa77e6928c.jpg
https://cimg1.ibsrv.net/gimg/www.mia...1df565bc60.jpg
https://cimg3.ibsrv.net/gimg/www.mia...1da2119336.jpg

I'm no expert, but I think you need more time with your IAC/PWM settings.

Your valve frequency is set to 480, and in the notes next to the field it, NAs are recommended in the 300 range. Make sure you set your min/maxes properly too (somewhere around 30-70ish?).
Then watch your log for PWM Idle Duty.

Notice how you blip the throttle and in the logs, your PWM drops immediately to 35 - that matches what you set in your your Closed Loop Idle Initial Values. Try softening the transition and see how your AFR reacts.

wow, you hit the nail on the head with this one.
I turned the IACV frequency down, and found that increasing the idle CL idle PWM caught the RPM a lot faster. I played around with it quite a bit and it isn't dipping like it used to. I still got it to sag a bit free revving in neutral when hot.. but it's better than it was.
I have found that I have to throttle a bit on cold start or it just dies right after firing up to ~1k rpm (see cold start log). Not sure why it's doing that but I'd rather the control at warmer temperatures where I'm at more often.
Hot starts also shoot up to ~2k RPM then come back down steadily. Still better than what it used to do with the low RPM drooping and nearly stalling.

I've got something new to tweak and work on slowly now - I appreciate the feedback and recommendation.

Nice job! Up your cranking pulse based on the current cold temp to get a bit more air on the startup. Once it fires up without the pedal, just move onto Afterstart enrichment - more fuel, more time (taper), or a bit of both.

For the remaining floating idle, you just need to start playing with the Initial Values table again and break up the vertical axis based on what's best for you. Example, not sure where you live, but maybe you don't need values at 0 degrees Fahrenheit. Break up the temps that are best to you, or look at other maps for guidance. Check the rest of your idle settings.

Once it's roughly dialed in, you're onto "Idle RPMs Advance Timing" to fine tune with timing, rather than the idle valve.