Graz clutch replacemnt

[Paul Robertson]

I am starting a new thread about my clutch replacement. I started a new thread rather than muck up Johns group buy thread. I replaced the stock clutch that came with the Graz transaxle from RCR. I pretty much only drive my car on the track (about 97% of my 4000 miles on the car are track miles). I was unhappy with the clutch engagement feel in high torque situations like hi speed upshifts. The stock clutch would slip just a bit. very tolerable but I had the engine out so I decided to take that opportunity to change it. Good news was the original clutch had very little wear and the flywheel was like new after 4000 hard track miles. My LS puts out 540hp and 560 tq so the clutch sees some juice.
I sent my clutch to GTE engineering (in Pompano Beach, FL, 754-205-0812) for relining. I went back with a ceramic/ kevlar mix. Ceramic one side Kevlar on the other. $2000. He uses your stock unit for rebuild. If the springs in your unit are shot then you will have to purchase a new unit which will drive up your cost. I have about 500 track miles on the new clutch and I see improved engagement characteristics both at high torque and low torque settings as well which surprised me . It feathers as well if not better than the stock unit.

 

[Paul Robertson]

Oh and I couldn't do the group buy in that I had less than a week to get the car ready for a track weekend. I sent my clutch out Thursday night and had the new clutch back Saturday morning (after $300) of overnight fees!

 

[HCF - John]

Hi Paul,
Thanks for sharing the experience and glad you're happy with the Kevlar clutch!It's a shame I missed you on the rebuild - we actually offer that service, as well. I know a little about GTE/PEGA and the Kevlar types we use are different; HCF uses a textile Kevlar composite product and GTE a molded Kevlar pulp product.

We tested (and continue to test as new products come on the market) over a dozen Kevlar linings before deciding on this particular Kevlar composite. It's the only textile Kevlar facing available and clearly outperformed the others in testing for durability and performance - the only real downside is it's the most expensive, costing 3-4 times as much as many of the other products. It's a patented product and made in the US. A derivative of this lining is used in top level professional motorsports, as well.

Our experience with the product goes back to the early 2000's and we've done about 500 units with it... about 100 of those are R8 discs.

I also wanted to share our experience with mixing the Kevlar and Ceramic discs. We tested multiple Kevlar/Ceramic combinations over the years and found they did not produce satisfactory results. The two materials break in at different rates, with the more aggressive Ceramic disc preventing the Kevlar disc from breaking in properly, which reduces lifespan. We can do them, but recommend against it.

We'd love to offer this Kevlar or Ceramic rebuilding service to anyone considering it - we offer the service for $1900.
Best,
John