C5 LS376/525 Return to Idle Stalling

[twig1107]

Car is a 2004 C5 stock PCM running a GMPP LS376/525 Crate (LS3 w/ ASA Cam). Car is a dedicated track car, headers, drilled aluminum flywheel. Running the LS3 Gold blade (capped at 95% TPS). Car was dyno tuned and runs like a scalded ape. The issue is that the car drops off revs very quickly and stalls 50% of the time. I've tried RussK's idle tuning and some other parameters. It's improved 50%, mostly by adding base airflow and follower airflow. I have not adjusted any spark, VE or fuel from the original dyno tune; just airflow and follower airflow/delay. I'm hesitant to make any further changes as further airflow changes seem to have limited effect.

Please let me know if you have any further tips for a beginner!

-TWIG

[Alvin]

In the beginning of your log your car is idling with a positive STIT and very high timing. Add airflow to the Base running airflow tables to get the STIT and LTIT inline but do this with an idle timing of around 18 degrees or so. 28ish degrees will give you max torque at an idle. By setting the idle up around 18 degrees you have up to 28 to go to to save a idle dip. Does that make sense? I think of it as "reserve torque" right now you are leaving nothing to reserve.

Honestly what your trying to fix (light weight flywheel/ dirty cam) is a very tough job for an experienced tuner. Making power on the dyno is easy.. stuff like this is hard.

[twig1107]

Thanks Alvin! I tried it making the changes, but the redux in timing made it worse. After further reading, I found a mismatch in my Octane tables vs Idle timing tables that I corrected. I'm also going to re-run the RussK idle plan as I only focused on airflow the first time around

[Alvin]

If you reduce timing, airflow needs to go up. It's just now you have spare timing available to save a idle dip where as now you do not. Does that make sense?

Airflow is a very slow correction. Timing is very fast

[TheMechanic]

Read a similar problem but can't seem to locate it. It addresses the alum flywheel. If I remember right an adjustment to underspeed/overspeed in spark tables.

[twig1107]

Alvin-
Very helpful. Thank you for the tips. Been working VE tables to ensure I'm not introducing fueling issues. The airflow vs spark makes a ton of sense. Most of my corrections have been airflow adders to date (PID, Follower, etc). Seems that they help, but I better understand the theory now...giving more air gives the spark more headroom to work it's magic. Will add more to base idle and reset idle spark advance to capitalize next.