I just converted my 1994 Z28, automatic, rear gears from stock 2.73 to Richmond Street-Strip 3.42's. I plan to modify the shift point tables (with TunerCat) to allow the 2>3 WOT upshift to happen prior to hitting the 5800 rev limiter. (lower 2>3 WOT shift MPH from 93 to 72). I used the info in the Transmission Tuning Tutorial sticky in this forum as reference.
My question is "Should I also ajust the MPH settings in the TCC engage/disengage tables to match the new gearing"? With the current MPH settings for 3rd & 4th gears my TCC is engaging at 20% higher RPM's than the old 2.73 rear settings. This is a daily running street car. I assume earlier lockup would be more fuel efficient and emission friendly. Just want to make sure this wont effect something else I may have missed.

 

Most tuners will also scale the TCC lockup tables when they are doing a gear swap. If you want to retain decent fuel economy, it would be a good idea to scale the TCC tables. You might even find you can lockup the TCC sooner with your new gears, which would bring even greater fuel savings.

The biggest danger here is "overpowering" the TCC. If you have a decent converter or a stock one in good shape, this shouldn't be an issue, but it's something to watch for. If, at part throttle you notice your RPMs creeping up, but you're still in TCC lockup, the TCC may be slipping. If you continue to drive this way, you'll burn up the TCC.

 

Vince, Thanks for the info. I used C.A.T.S Tuner 2.15 w/$EE Definition file. I set tire size and rear gear ratio in the speedometer calibration utility. From everything I could find no kickdown nor TCC tables were updated. I loaded the shift tables manually yesterday. It made a big change if street driveability. No more waiting for upshifts to happen. I Plan on doing the TCC settings next. ....Bob D.