Pontiac G8 Solutions

The Pontiac G8 arrives from Australia in GT / Sport Package trim with the front ride height at 660mm and the rear ride height at 559mm. It sits rather tall as though it were an AWD sedan. These heights are deceptive in that the rear wheel arch is lower and smaller than the front. The result is that while the ride heights are virtually identical the rear of the vehicle sits considerably higher than the front. It sits high in the bum. The OE dampers fitted to the G8 are NG – No Gas. These are basic oil and air units installed to keep the price point down – perhaps due to the increase strength of the Aussie dollar.

My initial drives of the G8 left me both impressed and disappointed. The VE chassis delivers almost everything we expected and yet disappointed at the same time. It is a tiger that feels tamed - it feels light and floats in sweepers and at high speeds. This is the Pontiac flagship and I wanted this tiger to claw through a turn. The car sits too tall, is sprung too soft, damped too light with a too much body lean and roll in. Even the ride is too light in my opinion

The all new rear suspension architecture is excellent. The integrity of the chassis design adds depth to the driving experience. The rear suspension has sufficient structure to support the most aggressive driving. The three point differential mount is a significant improvement over the GTO. The sub-frame attaches with a four point mount. The upper and lower control arms are another significant advance over the VZ chassis. Adding trailing arms puts the G8 on another level.

The G8 is an excellent car in OE trim. It has the potential to be dramatically better. The GTO arrived in the USA with a more traditionally tuned performance suspension as would be expected in a performance coupe. The higher than the sedan version of the VZ chassis coil and damping rates were judged to be too soft for a performance coupe by many owners in the USA. The G8 arrives as a performance sedan. The difference in obvious is ride heights, spring and damping rates. On your first G8 test drive you will notice that there is an enormous amount of body lean and roll. This is directly related to ride height, spring and damping rates. With smooth driver inputs and modest amounts of throttle the G8 will blast through twists and turns. As a driver you must ignore the lean and roll. The car will go where you point it.

G8 Low Hanging Fruit

With a more predictable rear suspension from the installation of Pedders EP1169, your next limiting factor is the ride height and damping rate. The G8 is a luxury performance sedan. You don’t want top turn this world class vehicle into a boy-racer kidney-belt required hot rod. To that end the changes in ride height for the G8 are roughly 20mm in the front with fresh Pedders 5851 strut mounts and 40mm in the rear. These changes allow the car to sit with a slight front to rear rake 622mm rear and 640mm front.

The G8 does use the same strut mount, the exact same strut mount as the GTO. We are finding 4 to 6mm of compression in fresh off the boat G8s. A modest increase in spring rate paired with Pedders nitrogen charged GSR dampers bring the G8 to life. Pedderised it drives like true performance sedan while retaining a luxury sedan like ride. It is easy to drive this car hard. The light sensation at high speed is gone. The rear step out, the rear bumpsteer, is banished. Suspension travel with your lowered ride height is long enough to be supple over most any road while delivering an amazing driving experience. Does it have more body lean and role than a maxed out GTO – it does. Does it ride better than a GTO – yes it does. Does it drive better than a GTO – yes it does.

Because the Pedderised G8 is so quiet and composed, high speeds seem to occur in slow motion. The G8 is a serious vehicle for the sophisticated driver that truly appreciates sophisticated automobiles. Because it is so balanced the Pedderised G8 is almost effortless to drive. Stability and Predictability are the primary characteristics that will leave you with SEGS. Take your time and learn the limits of your newly Pedderised G8 on a road course or an autocross. A Pedderised G8 is as weapon of higher priced vehicle destruction with minor suspension upgrades.

Special Attention Required

There are some concerns we have after getting into the G8 Pedderisation. While the wear of the OE strut mount bush in the GTO is well documented, there is some cause for concern with the use of the same mount in the G8. In the GTO, the upper spring perch / bearing plate had a rather modest angle. In the new G8 the upper spring perch / strut bearing plate is on a more aggressive angle. This increases the clearance between the strut tub and the tire sidewall. There is no cause for concern that we will see strut rub in the G8. What we will see, in my opinion, is wear in the strut mount as a result of the increased load on the strut mount from the angle of the spring perch / bearing plate. New information from GM indicates the design of the G8 bearing plate / upper spring perch will decrease the loads on the strut mount. When examined out of the car, it appears to be under load before being installed in the vehicle. According to GM, when installed in the vehicle there should be less load on the strut mount bush. We will all know from real world experience as we accumulate miles on the Pedders G8 and see more G8s with miles in Pedders Shops in the USA and AU. The update from Pedders Shops in AU -- they are seeing no unusual where on the G8 OE strut mount bush. We are seeing wear. The harder you drive the faster the G8 strut mounts will wear. Pedders 5851 has been designed for sever duty cycles making it the ideal strut mount for the enthusiast driver.

Before we wring our hands about this, the removal and installation of new strut mounts is roughly a 90 minute job. Replacing the mount with an OE or Pedders bit will be roughly $80 in parts. That is a small price to pay in annual maintenance cost to drive such an exciting luxury performance sedan. If you visit the BMW forums you will find that BMW has numerous issues with various suspension bushes. Even the ultimate driving machine has bush failures. Once again it is my opinion that the driving style of the performance luxury sedans contributes to the issues. Performance vehicles require performance based maintenance programs. An annual alignment, strut mount replacement including parts and labor is less expensive than picking up a cup of coffee at Starbucks on your way to work.

On the G8s we have seen on racks, the driver’s side parking brake cable was stretched across a hard metal sub-frame edge. GM / Holden / Pontiac seem to be aware of the chafe potential. The cable is protected by a yellow or gree plastic anti-chafe device. These two cars had already shown signs of wear in the plastic. We wrapped them with a piece of heat hose zip tied in place and suggest you do the same. It is a short list.

Pedderisation: Pontiacs, Businesses and People