20B 500rwhp - will ACT Heavy Duty Pressure Plate hold up?
 

20B 500rwhp - will ACT Heavy Duty Pressure Plate hold up? Or do I need to get the Xtreme

**NOTE**: this is NOT a drag car or car that will be 'launched', its my road race car.

The disk is not an issue as I use a racing ACT 6 puck solid disk, and it is very aggressive but perfect for road racing. The problem is the pressure plate, I need something that can hold 500rwhp without slipping.

I have searched and read threads touching on this, some say the Xtreme is to 'heavy', making the clutch pedal to hard to push and in some cases breaking clutch pistons and the bearing fork, et. Some said the Heavy Duty has better pedal feel and can hold 500rwhp just fine with the exception of hard launches.

I would get the Heavy Duty if I knew for certain it will not slip at 500rwhp during 'normal' acceleration up the gears, that is to say, not dead stop launching. Anyone have direct proof of this, something like 'ya I have a Heavy Duty and make 500+ and it did not slip on the dyno runs' or something similar.

On the other hand, I can be convinced to get the Xtreme if the cases I mentioned above are not typical, although if the pedal is REALLY stiff, it could be an issue of leg fatigue during a race LOL

Why not upgrade to a twin plate?

1: I already have the disk and flywheel setup, 2: money and time, so right now I just need an upgraded pressure plate ;-)

twin disk will come later :-)

see thread

https://www.rx7club.com/20b-forum-95...later-1064778/


Biting the bullet and getting the twin plate can't hurt

I would at minimum use the ACT
MZ010X - P/PL Xtreme pressure plate.

I have the Xtreme and a sprung 6 puck and it did hold my 420rwhp/415rwtq in my light FC, but there was one time I pulled off after a 4min session where I had to push the clutch and rev the engine a couple times to unstick the puck- so it was probably on the edge of slipping.

I never had a problem with the clutch pivot ball or pedal effort- I think those problems are with the MZ010XX - P/PL MaXX Xtreme.

I vote for going straight to Exedy twin disk. Got one in my FD and it is way more civilized yet holds very tight.

I loved the Act 6 puck /XT Combo, but damn did that thing have a STIFF pedal. It blew out the slave cylinder 2 weeks after installation. Make sure your slave and line are g2g with that PP.

Old thread revived.
Be aware that the stiffer the PP is thebmore stress it puts on the fork. There is a weak casting fork that is known to bend or break when using high clamp pressure plates.
I myself use solid disks and xtreme PP with no issues.

i think the xtreme with the iron cross is only rated to like 450lbs/ft, so it would live with 500 on the street ok, and just wear quickly. race car would eat it

Mazda updated the part back in 94 or 95, if you order a new fork from Malloy you're getting the stronger fork :icon_tup:

I have the act extreme pressure plate in my FC with their street strip disc (and prolite flywheel) and it holds at 460rwhp. My torque is under 400 ft/lbs. I have bent my fork and broken my ball pivot (on separate occasions) with this pressure plate. It doesn't slip at all.

Correct

I am selling a clutch and pressure plate from Clutchnet that handled 630HP with not problem.

Thanks for all the feedback all!!!

Freddyrx3, I already got an ACT Xtreme, thanks though.