AKtundra

Researching an LSx swap into a lifted off-road truck.

Back in "the old days", would lift, put on big tires, then regear the differentials to put acceleration, cruising RPM, and speedo, back in line with the drive train's original tire-size/drive train relationships.

Is the same process still necessary with the newer computerized drivetrain controls? How does the PCM programmer adjust for dramatically different tire size ? Does the tire size need to be known before the PCM can be reprogramed ? Will the diff's still need to be regeared?

aknovaman

iTrader: (7)

Find someone with tunercat software. I have found it does not have the speedo limitations as HP tuners. I use it on rock crawlers with extreme gear ratios.

tfi racing

iTrader: (2)

Same rules apply as before,the gear change was required because the engine didn't have enough torque to turn the new,much larger than before tires at a satisfactory rate.Speedo calibration is a separate issue,now done in the PCM software instead of physically changing the speedo gears in the transmission.