"Pedderised" and precision-aligned, the G8 is honed to a razor's edge, leaving you free to do what drivers do best-drive.
Last month, we took an '08 G8 and "redeemed" its factory suspension for a brand-new Pedders Track II system with Sports Ryder lowering coils, gas Sports Ryder struts, Sports Ryder bushings, and eXtreme adjustable sway bars. During the two-day installation, performed by Precision Motorsports of Florida in Odessa, we documented the parts swaps, as the factory rear control arms, differential, shocks, springs, subframe, front control arms, radius rods, steering arms, and front and rear sway bars were unbolted, and the G8's bushings, springs, shocks, and sway bars were replaced with Pedders components.
Pedders said that our newly "Pedderised" G8 would give us incredible performance on the autocross and road course. Before we began testing, however, a precision wheel alignment was required to fully exploit the capabilities of the G8's platform attributes and the new suspension components.
Pete Basica, president of Pedders USA, asked us, "Do you want the Pedderised G8 to be an autocross-only race car, or do you intend to drive it on the street and occasionally autocross or road race?" The reason he asked was to determine the amount of camber, caster, and toe-in to dial into the alignment. We answered that the G8 should be streetable as well as fun to drive on the road course.
The Pedders Track II suspension kit features Sports Ryder lowering coils, gas Sports Ryder struts, Sports Ryder bushings, eXtreme adjustable sway bars, and a strut tower bar. It's available for the G8, the G8 GT, the G8 ST, and the G8 GXP, at a price of $3,428 from Pedders USA (www.peddersusa.com).
"Precision wheel alignment is essential to optimum vehicle performance," Basica said. "Typical alignments from the factory or in tire shops have wide green ranges or large variances based on the OE specifications (see G8 Performance Alignment sidebar). At Pedders, we find those standards unacceptable. Our clients are seeking optimum performance, and that requires precision in all phases of a suspension build, including the alignment. To give the G8 its best alignment, we need to know exactly what will be its intended use."
Using the data previously collected from the Hunter alignment rack, Basica studied the measurements of the G8's factory alignment, taken before the installation of the Pedders suspension kit, and began to make some notes regarding where improvements could be dialed-in. While both HPP and Pedders agree that GM's new VE/ZETA platform is state-of-the-art, with increased negative camber and slight toe-in at all four wheels, increased caster up front, and the improved bushing design matched to more aggressive damping, coil spring, and sway bar rates, we hope to experience the ultimate in G8 suspension performance.
Pedders' eXtreme adjustable front sway bar (red) measures 26 mm, compared to the factory's 23mm production piece. The company designed a four-way adjustable system to tune the suspension to the driver and the track. We set it one hole in from the firmest setting.
We then asked Basica if biased-wheel settings (different camber, and/or toe, left-to-right) normally used to compensate for road crown and grooved pavement are used on the Pedderized G8 as they had been on the stock G8. He said, "Because superfluous motion is controlled by the Pedders Track II suspension, the alignment does not require biased settings. We can perform a road-course-precision alignment, and the car won't 'search' on public roads. The G8 will go exactly where you point it, when you point it."
The goals of a Pedders precision alignment also include improved steering-wheel response and steering accuracy. "The caster change we make is the result of less compliant radius rod and control-arm bushings and the radius rod arms being pulled forward with Pedders 5421 eXtreme caster-lock washers," Basica said. "These bits increased caster 1.4 degrees. The steering wheel now snaps back in aggressive autocross maneuvers."
He then showed us that though the stock camber settings were within factory specifications, the G8's driver-side wheel was nearly "wagon wheel" straight up, while the driver-side rear and both passenger-side wheels were negatively cambered (in at the top). "We increased negative camber on all the wheels to improve turn in," Basica said.
In all production G8s, a basic oil and air strut is standard. The Pedders strut is a nitrogen-charged gas and oil damper. The gas and oil work to provide a more controlled response to road imperfections. Every Pedders strut is pressure-tested before it leaves the assembly line. Typical OE and aftermarket coils are wound to a height tolerance of 15 mm; Pedders' coils are wound to a tolerance of 2 mm. Ride heights are measured on every Pedders coil before they're put into a box for retail sale. The spring rate is 30 percent stiffer than stock.
We also saw that the factory alignment had the left front wheel toed-in and the right front wheel toed-out; the Pedders alignment toed-in both front wheels very slightly. This can be done because the G8's platform is so good that it will drive exceptionally well with minimal toe. These toe values improve turn-in response and tracking through turns.
To complete the alignment, Basica increased rear-wheel negative camber (see G8 Performance Alignment sidebar) to further improve tracking and turning, and still get excellent tire life.
Finally, addressing the issue of tire wear, Basica said, "As the G8's miles accumulate, we're seeing that tire wear is controlled, even with very aggressive alignment settings. This is the direct result of the proper application of GM's billion-dollar VE/ZETA development budget to create a great platform, combined with tuning via Pedders suspension bits."
Testing
With the alignment dialed in to Pedders' specifications, we then traveled to Pasco Community College in Dade City, Florida, to collect data on the G8 at its testing facility. We brought two '08 G8s, a completely stock base sedan, which set our baseline numbers, and the G8 test car, identical to the base car except for the addition of the Pedders components. All testing was performed with a G-Tech RR Performance Meter courtesy of Tesla Electronics (www.gtechpro.com.)
Pedders' eXtreme adjustable rear sway bar (red) measures 20 mm, compared to the factory 18mm production piece. The recommended setting is one position from firmest to reduce the body lean dramatically while maintaining the neutrality and balance of the car.
Our first run was the 400-foot slalom to test the transient response of the suspension system. Normally we would use 600 feet, but there wasn't enough room to do it safely, nor was there enough room to run a traditional slalom test, where the speed is steady throughout. Instead of entering the slalom at the maximum safe speed, we had to enter accelerating.
The base G8 went first and set an exit speed of 52 mph. Although the cone set at the 100-foot mark was no problem for the car since we were still getting up to speed, excessive body roll took over at the 200- and 300-foot marks. At full throttle, the base sedan couldn't complete the slalom. The test drivers had to back off acceleration from 200 to 400 feet. The second to sixth runs on the slalom showed an improvement of 2-4 mph, however, adjusting tire pressure to 40 psi and then 44 psi showed no noticeable change in performance.
The Pedders suspension made a significant difference on how the G8 handled the cones. Our test vehicle clocked a 58-mph exit speed, 6 mph more than the base sedan on its first run. More importantly, it handled the slalom consistently and safely, exhibiting minimal body roll, and allowed the G8 to maneuver through the test cones at full throttle.
The Pedders Track II suspension kit is a purpose-designed, matched package. Here we see the front suspension components installed. Pedders says the result is greater than the sum of the individual parts.
Our second test was a 200-foot-diameter skidpad, and the base sedan went first. The goal of the skidpad is to increase the speed steadily to achieve the highest lateral acceleration reading before the tires "break loose," or the car can no longer maintain the same path. The base sedan produced a left/right average of 0.78 g of lateral force and an average test speed of 36 mph.
The Pedderised G8 left/right average was a whopping 0.88 of lateral force and had an average test speed of 39 mph. We repeated the test three times and received consistent results.
"There was significant understeer in the stocker," said Jay Heath, editor of VETTE magazine, who also aided in testing the vehicles. "The Pedders suspension virtually eliminated that trait, although there was still not enough power to induce throttle oversteer for our testing."
Conclusion
According to our data, the Pedders Track II suspension system for the G8 makes the Pontiac faster and more consistent than a base sedan in slalom and skidpad testing. Through the slalom, the Pedderised G8 is 8 percent faster and demonstrates a 13 percent improvement on the skidpad.
Translated to street and road-course driving, the Pedders Track II suspension gives the G8 a professional level of driver control, stabil-ity, and predictability. It allows the G8 to be driven fast with total confidence, and this improved control doesn't compromise its road manners. It's still comfortable to drive, with none of the harshness normally associa-ted with a performance suspension. Coming back home from the testing session on public roads, the G8 felt like the sports sedan it was designed to be.
G8 Performance Alignment
Although the G8's factory alignment settings are acceptable to the average daily driver, the Pedders alignment is aggressive and specifically tuned for sports driving. Using factory alignment settings with the Pedders components does not fully exploit the improvement in control. With this in mind, A G8 owner can still expect normal tire life with the Pedders precision alignment.
Having removed all the suspension NVH-compliant bushings from the factory rear suspension and upgraded the struts, coils, and sway bars with Pedders components, the Zeta/VE architecture delivers cat-like poise on the street and on the track.
Slalom PerformanceExit speeds, all in mph.RunBasePedderisedTire pressure, 36 psi 152582565835459Tire pressure, 40 psi45558 55459Tire pressure, 44 psi65660Average Speed54.558.66
Skidpad PerformanceRunBasePedderised Left/RightLeft/Right10.77/0.80g (36 mph)0.85/0.90g (39 mph)20.78/0.82g (36 mph)0.88/0.92g (40 mph)30.77/0.80g (36 mph)0.88/NA (39 mph)40.78/NA (36 mph)0.88/0.92g (39 mph)
Ride HeightWith 18-inch wheelsMeasured on the alignment rack in millimeters.LocationBeforeAfterChangeLeft front650635-15Right front649635-14Left rear643604-39Right rear645608-37
