I finally have it running good. I figured out that the spikes in the wideband readings were actually due to factors not directly related to fueling. The more I tuned the table, the better the wideband readings looked, but something in the ECM was drifting further from the expected values (maybe prediction coefficients?). Transitioning from no throttle to the slightest amount of throttle it was bucking like it was suddenly pulling timing, so I decided to go back to the stock VEs and try a MAF only tune.
According to the wideband my MAF was off 10%+- across the board... which happens to be exactly what the "MAF Airmass Filt" setting was set to. So the MAF was perfect with the stock Camaro SS settings.
Out of curiosity I did some math on the average value of the stock VVE vs. my tuned VVE. The stock values were higher on average by ~10%. Looking at the table under Airflow->Dynamic->VE Correction Factor->Initial the value for my elevation and normal temp was 1.10625... ~10%. This led me to believe the stock VE coefficients were also fine. Like I've been saying all along that they may not be optimal, but they should at least work reasonably well.
So I came to the conclusion that the correction factors were simply too conservative. I adjusted the "MAF Airmass Filt" to 0.05 and the "VE Correction Factor" for my area of the table to be near 1.0 and the car came to life. It was running great and the fuel trims looked great. The only problem was lugged a little more than it should at a lower RPM, low speed, and higher gear. It just seemed like a torque management adjustment was needed.
Comparing the CTS-V to the Z06 torque management there was significant differences in the "Peak Torque" settings. I had my tune setup to use the settings from the CTS-V which were higher across the board than the Z06. I switched back to the Z06 settings for this table and that cured the lug under high torque problem.
So now my tune has perfect drive-ability and stock configurations across the board. It finally feels like 650 hp and I'm sure there's still room for a few simple improvements. The "MAF Airmass Filt" is still set to 0.05 which I did confirm with the wideband that above 4k (MAF only) I'm 5% richer than the commanded AFR. Which under power enrichment and peak torque puts me at 11.54:1 instead of the commanded 12.15:1. I think if I turn off the stupid fudge factors, I should be at exactly commanded which are still conservative but will give me a little bump in power. Also, the stock CTS-V timing tables are more conservative than the Z06 (I assume because of the weight difference?). Anyway, I'm currently using the CTS-V spark timing so I think I can probably tune those to pick up a few more easy horsepower.
Here's my current tune. Hopefully if anyone else is crazy enough to drop an LT4 in an SS Camaro they won't have to go through the hell I went through to get it running.
Attachment 63287
Once I'm finished tuning I'll upload the final tune to the tune repository.
