High RPM shifting problems, SPEC Clutch?
03-26-2010, 04:08 PM
#1
On The Tree
Thread Starter
iTrader: (6)
Join Date: Jan 2002
Location: Arlington, TX
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
High RPM shifting problems, SPEC Clutch? Well I am having issues with my clutch much like the thousands of other people. I have a 94 RX7 with a 2000 T/A LS1 and T56.
Here is the situation.
If I start the car cold, let it warm up after 4 mins or so, and go make a 1-2-3-4 pass I am able to shift into 4th without issue, however if it has been warmed up for over 10 mins then my pedal will stick to the floor on the 3-4 and sometimes the 2-3 shifts. I can also just rev the car sitting still to 6500rpms for 4-5 seconds and it will kill my pedal.
I have replaced all of the hydraulics with no change in performance, I am using a US Brake 7/8 Master Cyl, a -4 braided Hinson Motorsports line and a AP Slave Cyl. I am also using some Motul 600 fluid which has killer dry and wet boiling temps, the braided line is pretty well shielded from my headers. I have bled it many times using every method that I know of including the Mighty Vac method, no change in performance. That leads me to the Clutch, I have a SPEC stage 2 clutch with ~500 miles on it, the pressure plate looks just like a OEM PP but painted blue of course, I have attached a photo below, does anyone else have any experience with this PP causing shifting issues at high rpm with the car at operating temperature? Is there any chance that Spec will take care of this situation and replace my pressure plate?
Here is the situation.
If I start the car cold, let it warm up after 4 mins or so, and go make a 1-2-3-4 pass I am able to shift into 4th without issue, however if it has been warmed up for over 10 mins then my pedal will stick to the floor on the 3-4 and sometimes the 2-3 shifts. I can also just rev the car sitting still to 6500rpms for 4-5 seconds and it will kill my pedal.
I have replaced all of the hydraulics with no change in performance, I am using a US Brake 7/8 Master Cyl, a -4 braided Hinson Motorsports line and a AP Slave Cyl. I am also using some Motul 600 fluid which has killer dry and wet boiling temps, the braided line is pretty well shielded from my headers. I have bled it many times using every method that I know of including the Mighty Vac method, no change in performance. That leads me to the Clutch, I have a SPEC stage 2 clutch with ~500 miles on it, the pressure plate looks just like a OEM PP but painted blue of course, I have attached a photo below, does anyone else have any experience with this PP causing shifting issues at high rpm with the car at operating temperature? Is there any chance that Spec will take care of this situation and replace my pressure plate?
03-27-2010, 01:03 AM
#3
TECH Fanatic
I had this exact problem when i first got my car and it would not go into fourth at the end of the track and sometimes when it was hotter it would not go into third. Did the drill mod no help, bought the tick master and it got alot better and i could go fourth but after that the pedal was almost dead. Found out later that my slave cylinder was leaking.
03-29-2010, 02:55 AM
#4
Teching In
iTrader: (3)
Join Date: Apr 2009
Location: central NY
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Mach1...I have the exact same setup in a 93 RX7 (Ls2-MN12--spec lightweight steel flywheel--stage 2 clutch--hinson SS line--oem slave --7/8 master)...... I have the exact same problem-----I pulled mine apart and have a half doller sized hot spot on mating sides of the pp and flywheel----- I am thinking the fluid is boiling----but am not sure.
03-29-2010, 12:24 PM
#6
Mach, what part number clutch do you have? When and where was it purchased? I assume from looking at the pics that you have an LS7 based assembly which uses a SAC-type pressure-plate. Check the springs on insure that they are equally compressed/extended. If the springs are not similarly spaced then this means that the SAC mechanism may be hung-up which would affect clutch release. Generally speaking though when an SAC issue occurs it affects shifts all the time, not ocasionally or only with temperature. I know you are confident that it isn't a hydraulic issue but, because the engagement/release is affected by temp it seems more likely that this is relative to a hydraulic issue. If you want to pull the parts and send them in for assessment I will be happy to examine them further. Just let me know. Thanks!!
