Pedders guarantees that a...
Pedders guarantees that a G8 with a Track II kit is more stable, predictable, and consistent on the road and on the track than the O.E. suspension. Can you tell which one of these two G8s has been "Pedderised?"
In "G8 GT First Drive" (Aug. '08), High Performance Pontiac reviewed Pontiac's flagship rear-wheel drive performance sedan and applauded its corner-carving abilities, giving credit to its well-engineered factory suspension package. But as good as the G8 is in stock form-and the reviews from the automotive press have been unanimous-we knew that if it was to be a serious track contender, improvements needed to be made in cornering and steering.
In fact, Pontiac designed the G8 with aftermarket performance modifications in mind. In an exclusive interview with us, GM Executive Director of Design, Body Frame Integral, Michael Simcoe, put forth the following challenge, "I'd love to see the G8 taken by High Performance Pontiac magazine and given a workout. If you think the G8 is good now, that means it's a fabulous base for you to get at it and turn it to something that's really personal and special for you and your readers."
The Pedders Track II kit offers...
The Pedders Track II kit offers extreme handling for autocrossing and road courses, and improvements over the factory components for launches at dragstrips.
With his challenge as the catalyst for our project, we contacted Pedders USA (www.peddersusa.com), the North American counterpart to Pedders Australia, a 59-year-old automobile performance company intimately familiar with the suspension architecture of the GTO and the G8 (and its Australian-marketed Holden Monaro and VE Commodore siblings).
According to Pete Basica, president of its U.S. operations, "Simcoe is absolutely correct. The design strengths of the G8 chassis are numerous. Front-to-rear weight distribution is very good. Engine placement is lower and farther to the rear than in the VZ Commodore that preceded it. The roll centers are excellent and the geometry of the independent rear suspension (IRS) is stellar. Incorporating virtual pivot point technology in the front suspension creates a vehicle that doesn't plow and is neutral. Without a doubt, the G8, either in base, GT, or GXP trim, is a car that is easy to drive fast.
Colt Mills from Precision...
Colt Mills from Precision Motorsports sets the alignment heads to get the baseline reading of the G8 in factory trim.
"The flaws in the G8, in the opinion of Pedders, stem from production constraints," Basica continued. "Spring rates are a bit too soft while the vehicle sits a bit too high. The basic oil and air struts are modestly tuned on the critical damping scale. Chassis bushings are over-engineered for noise, vibration, and harshness (NVH) standards and compromise the control of the vehicle. That said, many who testdrive and purchase a G8 will be thrilled with the vehicle as it out-performs literally every vehicle in its class. Again, it is the opinion of Pedders that the G8 should be delivered, or at the very least, available, from the factory with our suspension components pre-installed. A 'Pedderised' G8 is a formidable vehicle."
Basica promised that Pedders can turn every G8 into a track-taming superstar, so we procured the very first G8 manufactured for America (No. 1 of the first No. 888) and asked Performance Motorsports of Odessa, Florida, (an authorized Pedders dealer and service center), to outfit it with the Pedders Track II suspension with drop coils. Basica provided baseline measurements and led the work.
In Part I, we'll take the G8 up on the lift and learn what it takes to Pedderise it. In Part II, next month, we'll take our G8 and a stock G8 with factory suspension to the track and test them in the slalom and on the skidpad, and we will discuss the effects of wheel alignment changes on handling. Then we'll compare the results and see the improvements that a Pedders Track II suspension with SportsRyder lowering coils, Gas SportsRyder struts, SportsRyder bushings, and eXtreme adjustable sway bars provides over the factory's suspension in a stock G8 sedan.
With the rear wheels removed,...
With the rear wheels removed, the exhaust system from the headpipes rearward is unbolted and wrestled free to gain better access to the suspension system.
The removal of the rear stabilizer...
The removal of the rear stabilizer bar (the endlinks are already out) and struts begins.
With the aid of an impact...
With the aid of an impact gun and a set of metric sockets, the O.E. rear coil and strut assemblies are removed from each side by Pete Basica. Only the upper spring perch and insulator will be reused.
The driveshaft is unbolted...
The driveshaft is unbolted from the differential to allow sufficient movement to install the new Pedders differential bushings. Care must be exercised so that the pilot from the differential side isn't damaged when separating or installing the driveshaft. The male pilot and the female receiver are shown.
The aluminum three-point mount...
The aluminum three-point mount differential anchors the IRS. With the unit unbolted, the O.E. bushings are pressed out with a proprietary Pedders press plate and receiver and the new Pedders EP1167 differential bushings are slid in. This view is from the front of the vehicle looking toward the rear. (The male pilot that will insert into the female receiver on the driveshaft discussed in the previous caption is shown as well.) Pedders replaces the O.E. rubber bushing designed specifically to meet NVH standards with a urethane bushing designed for performance and comfort. Although traditionally we would compare hardness ratings through durometer readings, in this case the Pedders "bits" are superior to O.E. parts because of their design and the placement and size of NVH voids.
After the front two differential...
After the front two differential bushings were replaced, the rear is the third and final bushing (slip fit) from the EP1167 kit.
The differential will then...
The differential will then be re-installed and the bolts torqued to spec (see chart).
Using a 20-Ton Hydraulic H...
Using a 20-Ton Hydraulic H press, a steel-jacketed O.E. rear trailing arm rubber bushing is extricated from the O.E. arm. First, a Pedders press plate is placed between the bushing and the hydraulic jackshaft. It takes approximately 9.5 tons of pressure to press the old bushing out, then press the new Pedders EP7265 Rear Trailing Arm bushing in.
The rear trailing arm is shown...
The rear trailing arm is shown with Pedders EP7265 Rear Trailing Arm bushing installed.