Greg Lovell installs the GTO's...
Greg Lovell installs the GTO's KW rear coil spring during our suspension install.
If you've been reading along with the build of our '05 GTO, you're familiar with the nicknames the car has received-most notably, Shamu. From the factory, the '04-'06 GTO is an incredible performance car with a high level of comfort, but it's not the most impressive car on a road course or around the cones because it's designed to be a street car, not a race car. We want to shift the balance of our project car more toward the performance side of the scale since though it's driven on the street, it's a true weekend warrior at the road course.
As we've progressively improved upon some of the shortcomings of its chassis with brake and swaybar upgrades, we've yet to address some of the most important parts: the bushings and struts. After completing the GTO Suspension Buyer's Guide (HPP, Mar. '10) and getting a better idea of where to start, we contacted two companies offering excellent solutions for our Goat.
In the last issue, you read about the parts we used up front, why we chose them, and how we installed them. In this issue, we continue to do the same for the rear suspension. Andy Kollar of Kollar Racing offered us some knowledge on each bushing we would replace and why, and Jay Chen from KW Automotive served up some insight on his company's products.
The Parts
Andy provided Lovells crossmember bushings (N92350) to reduce wheelhop, rear control arm bushings (N61483) to sharpen suspension performance, and camber-adjustable rear control arm bushings (X63109). "The factory does not provide for camber adjustment in the rear," says Andy. "This kit allows you to correct the factory alignment and is a must for all cars with a 0.75-inch drop or more. Failure to correct the rear camber will result in accelerated tire wear."
The first step was to get...
The first step was to get the GTO onto the lift. Once it was elevated, we removed the 13mm bolts that hold the swaybar endlinks to the body and the three 15mm bolts that hold the cradle to the body. Next, with some leverage provided by a floor-jack handle, Greg was able to loosen the center 19mm bolt.
The cover should come off...
The cover should come off with the center bolt and reveal the crossmember bushing. Greg simply pried it out with a heavy flat-head screwdriver. If it's being stubborn, another way to remove this bushing is to place a large socket between the body and the bushing and lower the car slowly. This will free up the bushing.
These are the new Lovells...
These are the new Lovells polyurethane crossmember bushings.
In this side-by-side comparison,...
In this side-by-side comparison, we can see the difference between the worn factory bushing and the heavy-duty Lovells piece. The rubber bushing is brittle and very flexible, but the Lovells part is rigid. One compromise associated with using these new bushings is increased road noise.
After removing the 15mm bolt...
After removing the 15mm bolt that holds the rear control arm in, Greg got creative. There are two or three ways to get the bushing out. One is to use a press. This requires the removal of a bunch of parts and it just isn't a practical idea. Another way is to remove it with a torch, which could be dangerous, but is efficient. The third solution is to cut it out. This is difficult and messy, but very effective. The HPP shop had an air drill, so we loaded it with a properly-sized bit and started slicing away. According to Greg, "The best way is to sort of stab into it and keep going around until you've removed enough material that they easily come out."
With the upper pad in place,...
With the upper pad in place, Greg slides the the Lovells crossmember bushing in. Though it shows it is greased in the photo, Lovells says this bushing doesn't require it.
For our shock selection, we went with the KW V3 coilover suspension. Unlike the front, it uses a remote adjustable perch located in the factory spring location. The KW suspension retains the front McPherson-style coilovers, while the rear uses the factory inboard spring location, which reduces unsprung weight and shock static friction in the rear. Currently, there isn't a true coilover system for the '04-'06 GTO that has the coil spring mounted to the shock. In spite of this, KW assures us that this system is very effective, and it provides a similar setup for many other applications.
The rear springs included have a progressive rate that is more performance-oriented than the factory springs. This will, of course, come at some cost to ride quality.
These parts are more durable than the stock items. The bushings are polyurethane and should last the lifetime of the car, and the shock bodies are constructed from stainless steel. KW's website features videos of the shocks operating while completely submerged in saltwater. After a while, the traditional shock corrodes and freezes up. We won't have to worry about driving under water-for now (kidding).
After about five minutes,...
After about five minutes, Greg had made very good progress. We would already be moving on to the other side with a torch but this was the safer option.
As we suggested with the front suspension, it's best to have a professional install the components, or at least have one on hand, but the task can be handled by a mechanically minded hobbyist.
Greg Lovell of Anti Venom (no relation to Lovells suspension) was back in the HPP garage to help us with the rear suspension install. We found the back of the car was much less involved than the front, and we didn't need to use the press. There was, however, some drilling and creativity involved. Read on to find out more.
Swiss cheese!
The factory doesn't allow...
The factory doesn't allow for any adjustment of the rear camber. We are about to change that with these rear control arm camber/toe adjustable polyurethane bushings.
Because of their two-piece...
Because of their two-piece design, installation is as simple as sliding them in the control arm.
Here are the other rear control...
Here are the other rear control arm bushings. There's no way to get around this-they're hard to take out, and even more so to photograph while trying. They are held in by 15mm bolts and Greg brainstormed on how to get them out without resorting to the torch, as suggested by Andy. "I was under there for an hour cursing left and right trying to get them out," says Greg.
With the control arm bushing...
With the control arm bushing greased up nicely, Greg slides in the offset inner rod that will give the GTO camber adjustability.