GTO Package
Testing of the '06 GTO was performed at Horsepower Engineering in Houston, Texas. HPE has both a Dynojet Model 248 and a Mustang MD-1750 in-ground dyno. An in-car monitor is used to collect real-time air/fuel ratio (A/F) data on the load-simulating Mustang Dyno, while the Dynojet is used for final dyno results. The GTO required both part- and full-throttle dyno runs to dial in the computer program using LS2edit.
| Configuration | AIT | HP | RPM | Torque | RPM | + HP/TQ |
| Stock | 58.6 | 343.8 | 5,800 | 350.0 | 4,500 | - - - - |
| GTO Package & Tuning | 77.5 | 434.3 | 6,300 | 405.0 | 4,800 | 90.5/55.0 |
Nitrous Package + GTO Package
After the Nitrous package was installed, the car was tuned again to ensure safe operation. Timing was unaltered until 4,000 rpm where 1 degree was pulled out; then at 4,200 through the redline of 7,000 rpm, 2 degrees were removed. These changes, along with a slightly revised air/fuel ratio of 12:1 (versus 12:5:1) in the same 4,200-7,000 rpm powerband resulted in a drop in naturally aspirated peak rear-wheel horsepower from 434.3 to 421.0. Torque was also down from 403.2 to 393.5. The GM LS2 ECU is not capable of storing two separate tunes, so the final tune was optimized for nitrous use.
| Configuration | AIT | HP | RPM | Torque | RPM | + HP/TQ |
| GTO Package with Nitrous Tune | 69.0 | 421.0 | 6,300 | 393.5 | 4,800 | - - - - |
| GTO Package with Nitrous Package& Nitrous Tuning | 69.0 | 519.9 | 6,300 | 548.7 | 4,200 | 98.9/155.2 |
| Grand Total | - - - | 519.9 | | 548.7 | - - - - | 176.1/198.7 |