Pontiac Firebirds And GTO's Improved - More Power, Less Wrenching LS1-LS2 Dyno Tuning - Pontiac Tech

HP Tuners includes a wide range of tuning adjustments for the automatic transmissions in the Firebird and GTO. Included in the adjustments are changes for shift firmness, along with safety features such as transmission overtemp sensitivity and torque management.

On the Maximum Knock Retard vs. RPM vs. MAP table (Knock Retard table), you can see that the factory pulls 1-8 degrees of timing once knock is sensed.

Brian altered the Maximum Knock Retard vs. RPM vs. MAP table to pull between 1 and 4 degrees of timing once knock is present.

In the stock programming, the TCM table (Torque Reduction vs. Torque vs. Shift table) is reducing 8 percent of the torque when the engine generates 148 lb-ft of torque.

On the Torque Management screen, the "Diff Score" is for front wheel drive vehicles to avoid having the planetary gears in the transaxle seize to the pin on which they ride. For the rear-drive GTO it is already disabled and should stay that way. Brian then moves to the TM Abuse Mode.

The Abuse Mode is factory programmed to reduce torque starting as early as 1,536 rpm. By entering zeros in the table, the PCM disregards the programmed parameters.

This 8 percent factor is then referenced on the ECM table. Assuming that the sensors indicate there is no alcohol in the gasoline content, the table would look up the value closest to 8 (in this case 8.5) and pull 15 degrees of timing between shifts.

In stock form, the factory ECM allows the GTO to reach a terminal speed of only 155 mph before the computer starts reducing fuel and spark to limit top speed. Brian will change the values to 200 mph.

In order to completely remove all of the TM functionality, Brian will zero out the factors (shown). "We have seen no transmission failures on late-model GTOs as a result of deleting the TM at stock or near-stock power levels," he said.