Clutch Question
11-02-2014, 04:23 PM
#1
Rennlist Member
Thread Starter
Clutch Question
So yesterday I went to the drags with a buddy and it turned out to be an interesting day! When I arrived, the temperature at the track was 37F and the strip had a 25 mph head wind with gusts up to 40 mph.
Made my first run and things were looking good. Launched the car much harder than the past. Launched at 4200 rpm with low tire pressure which resulted in a 2.01 60 ft which was my best to date. However, the EBC did not work and I ran spring pressure for the entire run. Tried for a bit to figure out what happened but was running out of time if I was going to make a couple mores runs.
Decided to just use my MBC but I made changes to my WG spring and ended up setting the pressure too high. I had the overboost protection set to 23 psi and hit it in 1 st and 2nd gear which blew my run. Went back to the pits and lowered the pressure and went out for another run.
On the third run the clutch was like butter, slipping all over the place. Right after the run I took it out on the street and I could get it to slip at about 15-16 psi around peak torque. After that I called it a day and figured a clutch was a job that I would have to be done this Winter.
Today I took the car out and I cannot get the clutch to slip. There is a real steep hill not far from my house and pounded the car on boost, tried bogging in high gear and still no slip.
My question is what happened? Was the clutch over heated? Did I mildly glaze the clutch and then wore off the glazing? Clutch is a Spec Stage 3 Hybrid with a Spec pressure plate and aluminum flywheel. Any input appreciated.
Made my first run and things were looking good. Launched the car much harder than the past. Launched at 4200 rpm with low tire pressure which resulted in a 2.01 60 ft which was my best to date. However, the EBC did not work and I ran spring pressure for the entire run. Tried for a bit to figure out what happened but was running out of time if I was going to make a couple mores runs.
Decided to just use my MBC but I made changes to my WG spring and ended up setting the pressure too high. I had the overboost protection set to 23 psi and hit it in 1 st and 2nd gear which blew my run. Went back to the pits and lowered the pressure and went out for another run.
On the third run the clutch was like butter, slipping all over the place. Right after the run I took it out on the street and I could get it to slip at about 15-16 psi around peak torque. After that I called it a day and figured a clutch was a job that I would have to be done this Winter.
Today I took the car out and I cannot get the clutch to slip. There is a real steep hill not far from my house and pounded the car on boost, tried bogging in high gear and still no slip.
My question is what happened? Was the clutch over heated? Did I mildly glaze the clutch and then wore off the glazing? Clutch is a Spec Stage 3 Hybrid with a Spec pressure plate and aluminum flywheel. Any input appreciated.
11-02-2014, 06:08 PM
#2
Race Car
Too much heat. The organic material doesn't like it.
You may have been able to make another rub if you could have let it cool off.
This is why I like the Feramic material. It bites when heated still.
Launching it harder initially probably caused it.
If I were you, I would use your current pp and get a disc from Dave.
You may have been able to make another rub if you could have let it cool off.
This is why I like the Feramic material. It bites when heated still.
Launching it harder initially probably caused it.
If I were you, I would use your current pp and get a disc from Dave.
11-02-2014, 10:47 PM
#3
Rennlist Member
Think brake fade... I love (love) the KEP/CUP combo for the street, but 4200 rpm launches are probably too much to ask of the little guy. The South Bend disk very street friendly -- just a hint of shudder at lights -- but would get my vote for your next try.
p.s., clutch jobs aren't as bad as advertised. You can do it over a weekend on jackstands if properly motivated.
p.s., clutch jobs aren't as bad as advertised. You can do it over a weekend on jackstands if properly motivated.
11-02-2014, 11:06 PM
#4
Rennlist Member
Thread Starter
Too much heat. The organic material doesn't like it.
You may have been able to make another rub if you could have let it cool off.
This is why I like the Feramic material. It bites when heated still.
Launching it harder initially probably caused it.
If I were you, I would use your current pp and get a disc from Dave.
You may have been able to make another rub if you could have let it cool off.
This is why I like the Feramic material. It bites when heated still.
Launching it harder initially probably caused it.
If I were you, I would use your current pp and get a disc from Dave.
Think brake fade... I love (love) the KEP/CUP combo for the street, but 4200 rpm launches are probably too much to ask of the little guy. The South Bend disk very street friendly -- just a hint of shudder at lights -- but would get my vote for your next try.
p.s., clutch jobs aren't as bad as advertised. You can do it over a weekend on jackstands if properly motivated.
p.s., clutch jobs aren't as bad as advertised. You can do it over a weekend on jackstands if properly motivated.
11-03-2014, 01:11 AM
#5
Rennlist Member
The cross-over stays in place unless you have that super early version without a separate elbow going to the wastegate...
11-03-2014, 08:12 AM
#6
Rennlist Member
Thread Starter
Trending Topics
11-03-2014, 12:03 PM
#8
+2 for South Bend. I AX a lot - usually 10 runs/person/event minimum, 5 events/year minimum... x 2 drivers (me, and my wife).
That's a lot of aggressive, clutch-slipping starts per year. And the SB clutch has held up great. No slip so far. If anything, it seems gripper/grabbier when it's got a little heat in it.
That's a lot of aggressive, clutch-slipping starts per year. And the SB clutch has held up great. No slip so far. If anything, it seems gripper/grabbier when it's got a little heat in it.
11-04-2014, 01:12 AM
#10
Rennlist Member
11-04-2014, 08:34 AM
#11
Rennlist Member
Thread Starter