05-02-2005, 11:18 PM
In January, I decided to proceed with my suspension project. I had already replaced the front sway bar with the Weltmeister, installed KLA rear drop links, Dynatech STB, and Racers Edge control arm spherical bearing bushings (they are holding up just fine), and rear sway bar bushings. For the 2005 project I replaced the stock M030 control arms and struts with Charlie arms and Ledas/450# Hypercoils and added the Dynatech camber plates (yes, I know what they cost) to add a little vertical axis compliance compared to the full race (cheaper) camber plates. While I was there, I installed the big blacks with Pagid blue pads clamping on OEM perforated rotors (Please, no debates. See the old threads if you are compelled!). A 5/33 proportioning valve replaced the stock unit. In the back, I went full coilover with Ledas/500# Hypercoils, replaced the torsion bar bushings with Racers Edge Delrin, and the bars with 10 mm diameter ones. The rear brakes were not changed, the Pagid blues have been there for several years with almost no wear. That may change with the new proportioning valve. Time will tell.
The ride height was reset to be the same as the Club Sport (lowest factory ride height for 968 NA models). I've been running at this height for 3 years now and the splitter is as close to the road as I want it to go. When weighed at Roebling last month, the diagonals were only 13# different. Total weight with 5/8ths of a tank and yours truly was 3350#. I always have liked the full figured type.
Replacing the proportioning valve required removal of the windshield washer reservoir. With it out of the way, the job was easy.
Removing and reinstalling the torsion bars was a PITA, mostly because of my "read the instructions once and go do it" approach and the fact that I was working to a deadline. Indexing the 10 mm bars was not important since the spring rate is inconsequential. Under those conditions, I was doomed to miss a step or two and I was barely finished in time for tech on Friday before the DE weekend. If you decide to do this, read the Elephant Racing write-up on Rennlist. You do not have to drop the entire suspension to do this job. The 968 is even easier that the 944 because, after removal of the aero fairings the torsion bars can be pulled straight out without tilting the torsion bar tube as described in the Elephant Racing description.
Everything else was pretty straightforward. Good tools, a set of pry bars, an air impact gun and air ratchet were very handy.
All of my suppliers were great! Here they are:
Dynatech Scott Reynolds Camber Plates and STB
Sunset Porsche Jim Brakes etc
HRM Jason Lee Charlie Arms
Racers Edge Karl Poetl Ledas, Hypercoils, bushings, rear coilover adapters, t-bars
Frozen Rotors Bill Groschen Cryogenic treatment
Paragon Products Jason Burkett Pads, fluids, tools
Porsche of N Orlando Jim Alignment
Zotz Garage Donnie Mechanic
After double checking all of the torques, I had the car aligned by Jim at Porsche of North Orlando. Here is the before and after.
I made a mistake when I had the camber set at -0.75 deg. The camber plates provide 2 deg change so my max at the track would be -2.75. I will change the street setting to -1.5 so that I have -3.5 available for DE. Toe changes as the strut is moved through the camber range, 1/4 inch in my case. So we set the street toe at 1/8 inch toe-in. At max camber its 1/8 inch toe-out. I have not decided to change this or not.
Ride is firmer than M030, there should be no surprise here. Its 270 miles to Roebling from my house and I slowed down in the same spots that I always do. I don't want to hit an unexpected pothole, but that is no change from before. Road noise is definitely increased. The stereo would have to be turned up to painful levels to drown it out, so I didn't. After about 400 miles I didn't notice it so much. So, if you like peace and quiet in you 968, I would not recommend these mods. If your wife/GF likes a Caddy, she won't like this.
At the track, first session: HUGE understeer! I'm back in the paddock after 4 laps. After resetting the camber plates from street to track settings I was ready for session #2. This time the understeer was minor and I was able to remove most of it with small adjustments on the Ledas. Braking was changed in that less pedal pressure is required to evoke ABS. The brakes modulate fine, the car was not tail happy, and fade was non-existent. I expect to see reduced wear rates in pads and rotors as a result of the brake mod. Compared to my last session at Roebling, lap times improved by 2 to 3 seconds. I believe my 1:28 on about 6 different laps compares favorably with the PCA F stock 1:22 to 1:31 qualifying times posted at Roebling in 2004. I hope to rapidly become more confident and squeeze out a little more as the seat time piles up.
Of course, the turbo install this summer may cloud future improvements due to the suspension.
Here are some more pictures:
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The ride height was reset to be the same as the Club Sport (lowest factory ride height for 968 NA models). I've been running at this height for 3 years now and the splitter is as close to the road as I want it to go. When weighed at Roebling last month, the diagonals were only 13# different. Total weight with 5/8ths of a tank and yours truly was 3350#. I always have liked the full figured type.
Replacing the proportioning valve required removal of the windshield washer reservoir. With it out of the way, the job was easy.
Removing and reinstalling the torsion bars was a PITA, mostly because of my "read the instructions once and go do it" approach and the fact that I was working to a deadline. Indexing the 10 mm bars was not important since the spring rate is inconsequential. Under those conditions, I was doomed to miss a step or two and I was barely finished in time for tech on Friday before the DE weekend. If you decide to do this, read the Elephant Racing write-up on Rennlist. You do not have to drop the entire suspension to do this job. The 968 is even easier that the 944 because, after removal of the aero fairings the torsion bars can be pulled straight out without tilting the torsion bar tube as described in the Elephant Racing description.
Everything else was pretty straightforward. Good tools, a set of pry bars, an air impact gun and air ratchet were very handy.
All of my suppliers were great! Here they are:
Dynatech Scott Reynolds Camber Plates and STB
Sunset Porsche Jim Brakes etc
HRM Jason Lee Charlie Arms
Racers Edge Karl Poetl Ledas, Hypercoils, bushings, rear coilover adapters, t-bars
Frozen Rotors Bill Groschen Cryogenic treatment
Paragon Products Jason Burkett Pads, fluids, tools
Porsche of N Orlando Jim Alignment
Zotz Garage Donnie Mechanic
After double checking all of the torques, I had the car aligned by Jim at Porsche of North Orlando. Here is the before and after.
I made a mistake when I had the camber set at -0.75 deg. The camber plates provide 2 deg change so my max at the track would be -2.75. I will change the street setting to -1.5 so that I have -3.5 available for DE. Toe changes as the strut is moved through the camber range, 1/4 inch in my case. So we set the street toe at 1/8 inch toe-in. At max camber its 1/8 inch toe-out. I have not decided to change this or not.
Ride is firmer than M030, there should be no surprise here. Its 270 miles to Roebling from my house and I slowed down in the same spots that I always do. I don't want to hit an unexpected pothole, but that is no change from before. Road noise is definitely increased. The stereo would have to be turned up to painful levels to drown it out, so I didn't. After about 400 miles I didn't notice it so much. So, if you like peace and quiet in you 968, I would not recommend these mods. If your wife/GF likes a Caddy, she won't like this.
At the track, first session: HUGE understeer! I'm back in the paddock after 4 laps. After resetting the camber plates from street to track settings I was ready for session #2. This time the understeer was minor and I was able to remove most of it with small adjustments on the Ledas. Braking was changed in that less pedal pressure is required to evoke ABS. The brakes modulate fine, the car was not tail happy, and fade was non-existent. I expect to see reduced wear rates in pads and rotors as a result of the brake mod. Compared to my last session at Roebling, lap times improved by 2 to 3 seconds. I believe my 1:28 on about 6 different laps compares favorably with the PCA F stock 1:22 to 1:31 qualifying times posted at Roebling in 2004. I hope to rapidly become more confident and squeeze out a little more as the seat time piles up.
Of course, the turbo install this summer may cloud future improvements due to the suspension.
Here are some more pictures:
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(This post was last modified: 05-02-2005, 11:26 PM by mikeo.)
