possibly but this thing doesn't have 4k miles on it yet and every gasket is felpro or mahle

 

Ive seen alot of tunes that had been done pretty good but 99% of them had really really low timing right there were you brake stall it at. so its weaker than pond water.
My tahoe was horrible in 4hi with 33" mud tires and 4.10s with a heads cam 6.0 till i started datalogging and figured out negative timing doesnt make power.. Went from -10 to 18* and it come alive!
If you cold post a datalog of brake stalling it and a couple off idle stabs. That would help us alot on determining where your issues are.

 

Upload the file here as an attachment

 

from awhile ago but no air/fuel/spark changes have been made since

 

Why is stoich 12.49?

Part of your problem is the 4L80e like said before, not easy to get things going with a heavy truck with big tires. The 4L60e has a better 1st gear for burnouts.

 

I thought by dropping it a point or 2 would add a little fuel when I was playing with it but according to the wideband it didn't do **** and I just haven't when back and changed it. I agree on the 4l60 haveing better ratios even with all the engine mods I can definitely tell it soaks up more power and drives diffrent

 

OK I made two base tunes. one with stock injector size and one with the larger ones. 2 is the larger injector. Nothing else has been changed. MAF is still disabled and the ve is back to mostly stock minus 10% in the idle range. I didnt want to use the previous ve table since the stoich was way off unless your running an ethanol mix. Anyhow give this a shot and let us know better, same or worse

 

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4L80E is not really a problem for burnouts with the right converter and something that actually makes some low-end torque. My old 350 in a heavy *** Express conversion van would break 31" tall 275 wide tires loose with a 3.73 gear and stock B82 converter.

My guess is probably some torque management limiting the torque output when you hammer on it. TQ management and abuse routines will both kick in and cut the timing if not addressed correctly.

 

It died when I first put it in gear, but it doesn't surge or die getting on or off the loud pedal. It very successfully and quietly left the parking lot without turning heads. I corrected displacement before loading, but it still seems very lean throughout acceleration, bouncing from 15-16. It was as low as 13 during very light acceleration and idle. It also smelled HOT when I pulled in the driveway, but definitely lost power everywhere except off idle. It gained some manners and lost some power. Here's the data log.

 

excellent ok I’ll have a look. Which tune file did you use? 1 or 2