After allowing the G8 GXP to cool down, we checked the tire pressure. The factory recommends 36/39 psi (front/rear) and, with the heat, pressure had increased to 44 psi in all four tires. We lowered the rear tire pressure to 32 psi, in an attempt to improve traction.
The fourth pass, with 32 psi in the rear tires, was the best of the day. With a 2.03 60-foot time, it stampeded the traps to a 13.52 e.t. We had found the magic combination: Lower the rear tire pressure, launch at 2,500 rpm, and shift into Fourth gear at the very last possible moment. It worked. We tried slightly lower, and slightly higher pressure afterward, but 32 psi worked best.
The results of our dragstrip testing are shown in uncorrected numbers. Gainesville Raceway sits at 147 feet above sea level. The temperature ranged from 84.5 degrees to 94.1 degrees and humidity ranged from 67 to 62 percent. Density altitude was calculated at 2,886, so we will use a correction factor of 0.9653 for e.t. and 1.0367 for mph for a Best Time Corrected of 13.05, as shown in the chart.
Skid Pad And Slalom
As mentioned, the G8 GXP comes standard with the FE3 Sport Suspension System. According to Pontiac, this is a marked improvement over the FE2 system offered in the base and GT models. Its features include 23mm front and 20mm rear sway bars, and special shocks and springs. Having tested a base G8 before and after adding a Pedders Track II suspension package ("Suspension Redemption," Jan. '09 and Feb. '09), our expectation was for the factory FE3 suspension to rival the Pedders Track II suspension in handling capability. This was not the case. Though the factory's FE3 suspension gave the G8 GXP great street ride-and-handling characteristics, in comparison to the Pedders suspension we installed on a G8 last year, the GXP's FE3 suspension did not offer the razor sharp response that our Pedderised G8 has.
Slalom testing was similar. The FE3 suspension offered marginal improvement over the FE2 suspension standard in the base and GT models. We won't compare the figures directly, however, because the prior tests were done at a different venue. The FE3 suspension allows the G8 GXP a 54-56 mph slalom exit speed.
Street And Highway Driving
In my opinion, the G8 GXP is the best overall- performing musclecar ever created by Pontiac. It accelerates like a Ram Air IV and has the top end that Fireball Roberts would have had a tough time beating at the Daytona 500. Although we did not have access to high-speed testing, Pontiac told us that the G8 GXP is capable of 155 mph, and its speed is electronically limited so as to not to exceed the speed rating of the factory tires. What is the G8 GXP actually capable of? Our engineering sources told us it can do 185 mph.
How does the G8 GXP feel in real-life conditions? Powerful, nimble, comfortable, and spacious are all worthy adjectives. In commuter traffic, it accelerates and stops perfectly, of course, the LS3 and Brembo front brakes are due their credit in these departments. On the highway, it cruises 65 mph comfortably at 1,500 rpm, but can be called upon to navigate a passing lane with full confidence. Our test car even managed 24 mpg on the highway, although around town driving brought its fuel-economy down to the 16-17 mpg range.
Conclusion
The G8 GXP gets an A+ in stock form, when evaluated as a street vehicle. It is a well-engineered package that stays true to its Pontiac heritage in performance and style. Add to that its ride control and sophisticated drivetrain and it's a guaranteed winner.
Evaluating the G8 GXP on a test track reveals that Pontiac left room for the aftermarket and GXP owners to take it to the next level. Companies like Pedders Suspension, MAST Motorsports, BMR, and SLP have already come to market with the components needed to make the GXP excel in competition, and more companies are adding G8 GXP hi-po parts to their performance catalogs as time goes on. All hail Pontiac's last musclecar.