Thoughts on FUEL & SPARK

[Coz_KB95]

First and foremost, want to thank Decipha! Mike, I can imagine just how busy you are, but your taking the time to chime in on my questions here is truly appreciated and has helped steer me in the right direction, especially when I was going down some fairly deep and twisted rabbit holes.

I feel like I've made fairly good progress, and I've learned more than I ever thought I would know not just about what the ECU is doing, but about what these engines are doing. Each time I read the writeups, I learn something or realize something ... and I've read them what feels like a thousand times :)

With that said, I finally worked up the courage to take the car out for a drive with the supercharger belted up. The tune was in a place where I felt fuel was 99% dialed in when warm and spark was in a safe place based on previous NA test runs. Idle still needed some work (which I have since done and gotten much better, amazing what installing a few MAF screens will do!) and I do still have an intermittent issue with stall on declutch coming to a stop. I feel that issue is Dashpot decaying a bit too quickly in the lower RPMs. I've made some tweaks and am waiting for some decent weather to prove them out.

With all that said, here's why I'm posting. I think I've setup Fuel and Spark to be relatively safe. I'm running a 2.2L Kenne Bell. Boost is coming in at 9-10psi and it comes in suddenly, which is a ton of fun on the street, but also makes me very nervous in terms of Fuel and Spark coming to target values when I nail the skinny pedal. So far, no pinging or misbehavior I can hear or feel. I'm looking for anyone's opinion related to maybe tightening up Fuel and Spark specifically for the boost behavior on these Positive Displacement blowers. The ramp up on Perload for Fuel seems to take me immediately to the top of the Base Fuel table and .800 Lambse. I've touched 2.00 perload on more than a few occasions which I believe is safe. I'm wondering if I might be leaving anything on the table with the way I have Lambses set at .90 and 1.05 perload.

For Spark ... I have basically flattened everything above .50 LOAD to head straight to 19 degrees max total. I've done this because I know it's safe as this setup ran 19 degrees locked out at the distributor for 4-5 years. No concerns for scaling load as I'm maxing out at 1.4 -1.5 which leaves me some headspace ... Is there some guidance to tweaking or dialing spark further with these Positive Displacement blowers. Is it safe to add a degree or two as RPMs increase? I'm not trying to milk numbers out of her, she gets up a goes really well. Just wondering what makes sense and would make the engine 'happier' as it transitions into Boost and pulls through the RPM range.

One thing to note: ACTs are expectedly on the hot side. I have my ACT sensor plumbed into the discharge manifold on the Kenne Bell and I do not have my Water/Meth kit setup as of yet. That will be a project for next summer, as the car will be parked for the winter.

Attaching my recent drive log with a few WOT runs (and corresponding stalls coming to a stop) and the tune file that corresponds to that drive. Inviting folks here to take a look and provide their thoughts.

Drive_Log~v2.3_T4M2_95KB_10_18_2025~.xdl

(1.82 MiB) Downloaded 26 times

~v2.3_T4M2_95KB_10_18_2025~.bin

(56 KiB) Downloaded 25 times

Thanks in advance!