Has anyone been able to get to the 1-2 shift on a C7 Z shift where they want it but not overshoot it? As well as getting the TCM to lock when it should. I think the trans is the only thing holding me back to get a 8 second pass.

I have written a TUTD 2nd gear tune but I'm just afraid to use it for fear its wrong. 2nd gear is probably my best best but I'm still getting my best 60's launching in 1st gear-1.29-1.30.

Here is the tune and log.

10 27 23 new tcm tune update 1 shift 6200 increase line pressure-3.hpt10 28 23 run 4 904.hpl