[kurts]

Has anyone seen an iron disc do this? Large portions of material missing. This has 10 1/8mi hits on it on my tar/chip road. No burnouts. It was supposed to be 5135, this one came from spec clutch as they had it on the shelf 9" 1"-23 metric, and noone else could get it done (crower, bonifante, cale, ram, ect.)

The car is an awd eagle talon, made 500ft*lbs and 725hp on a superflow. 3000lbs and has been 9.80/145 on this combo. I do not use a 2-step to launch it. Just sort of hold it about 7500, and ease the clutch out quickly while going wot fast. Pulls it down to about 5500 and 15psi and takes off from there. Goes mid 1.5's like that and I'm happy with that - the driveline is barely qualified to be in a golfcart. Anyway this had a 2000lb diaphragm pressure plate, and it would slip a bit on the shifts. This has a face plated transmission, I shift at 9000ish, just dabbing the clutch. I use a timing retard on the clutch switch to keep the rpm from flaring and keep it off the main rev limiter at 9500. Gears are 3.12/2.03/1.47/1.08, and the rear is 4.26. 26x9.5x16 hoosier qtp tires.

ACT puck discs do the same thing. Putting a $57 china pos in it now to get through next weekend.

 

[ssstang]

Yes, I've seen that many times. Your clutch/disc has been overheated which caused the sintered iron friction material to delaminate. Your clutch adjustment was probably on the loose side and slipping pretty good. Loose is fast but it comes at a cost. The disc pictured was an Ace 5135.

 

[kurts]

If that is really overheating, that sucks. From experience with this car, a rag disc will take WAY more abuse. I have friends that are truck pull guys that beat them up so bad they turn the input shaft blue, and they don't chunk out like this. The pressure plate isn't even colored at all.

 

[ssstang]

Different compounds for different applications. The heat is generated from the slip at launch and gear changes. Hot lapping exaggerates the matter...if you do it. A tractor pull clutch doesn't use a 5135 compound. Who makes Spec sintered iron disc? China possibly?