C6Z control arm bushing carnage

[Aaron Pfadt]

Think the stock bushings on your Z are up to the task of a track day? Think again!

I was doing a once over on our C6Z after two intensive days of track testing a bunch of existing and new suspension products at Reno Fernley last week (watch for results and video soon) and found some bushing carnage.

We were testing the Z in a stock configuration and adding suspension components to determine some lap time deltas. With that we retained the stock control arm bushings for all the testing because of the difficulty of changing bushings at the track.

Both of the front upper control arms had severe slippage of the bushings. The interesting thing is that is must be from rotor torque. The upper control arms are both pulled forward on the chassis. I would have expected them to be pushed back (toward the rear of the car) from holding the car back under braking. Instead the torque on the upright assembly under braking rotates the upper control arm forward.

Here is a little video of the spindle under braking also. Look at the rotor glow! I'm in the market for some new rotors

Anyone know how to embed YouTube stuff here on this forum???





Looks like a perfect time to put in a set of our Pfadt C6Z bushings. Also note our Pfadt camber kit installed in the pictures. We put some tape on the shims to keep them from falling out while we were swapping components.

I'll post a full write-up on our testing very soon. It has lots of interesting data.

later,
Aaron

[Tony Skarbic]

Gret information. I wonder where these parts originated from, USA or?

[No Doubt]

Depending on use, this has been a known issue on both the C5 and C6. The parts themselves are not the problem, but rather the design of the A-arms themselves. Specifically, the fact they use rubber bushings as well as the method used to retain them.

Polyurethane virtually eliminates the issue because, unlike rubber compounds, they don't deform like rubber and thus can't protrude. They are, however, a wear item and are more prone to noise, especially if not properly lubricated.

Thus, as with most things, there are advantages and drawbacks to both methods.

[Aaron Pfadt]

Originally Posted by Tony Skarbic

Gret information. I wonder where these parts originated from, USA or?

I think a lot of the aluminum suspension and brake parts on these cars come from Australia. They are a very big exporter of Alu and have started to do a lot more 'value added' processes.

The bushings are pressed into the arms here in the US I think. The problem is just that they weren't designed to take the loads that sticky tires will put on the suspension. I'll post some video later that shows the lower control arm bushings deflect under use. It is really amazing.

-Aaron

[proexpert]

Wow that video is cool thanks for sharing that and all the other info.

[jub jub]

Great info and thanks for posting.