I just upgraded to 35s but I have yet to adjust for the different tire size. The auto HATES the tires with a passion. I have to give at at least 75% throttle up a hill to get it to downshift some times and it looses 5-10 miles per hour before it tries on its own if im using cruise control. Will a procal fix the shifting pattern and make it not feel so sluggish or is it just going to adjust my speedo correctly? I dont mind the speedo being off for now, but the sluggish shifting is killing me. Ive got 4.10 gears as far as I know so its a bit on the low side but still shouldnt be THAT bad I would think.

 

Shift points are synced to throttle position, rpm and speed. By changing diameter of tires, the formula is off. Using a ProCal will calibrate the tire diameter, fixing speedometer / odometer / shift points. To eliminate your transmission from constantly changing gears turn off over-drive. The only real way to improve throttle response is to change ring and pinion gears. More drastic is a supercharger to get power at lower rpms.

 

The procal is a great little device, well worth the price for all of the functionality. But, it is NOT a replacement for having the proper gearing!

It was mentioned above, and I'm sure you have seen it in other threads. Until you get around to regearing --> press the OD Off button every time you get in.

 

Gears are the best thing you can do for a 3.8 with bigger tires. One of the most overlooked mods that make the most difference.

 

No the ProCal will not fix the sluggishness, only recalibrate the shift points. A Superchips Flashpaq will address other issues inherent with the factory programming like the poor throttle response as well as let you recalibrate for larger tires and later for gear change.