user 9348703

Hummm yeah... I thought you said ACT makes OS and I called BS though. hummmm maybe I need to go check again.

Bu............................t You did say "havent you ever looked at a ACT clutch you can see OS gieken scratched ok" Right? That would be good proof....hehe

jspecracer7

Strange that the OS Giken super single clutch and the ACT extreme engage differently...I've seen the ACT up close...when it's done....it's done. With the OS Giken, even if the disks are past their wear thickness, the plates can be reused as long as they are in tolerance. I've had my OS Giken for a LONG time(2 1/2+ years). I rebuilt it with new plates/disks about 2 years ago and it's still holding strong....I'd like to see a daily driver ACT extreme go thru the same abuse I put my twin thru AND last that long.

Tom93R1

iTrader: (2)

Funny, I had a similar problem with my ACT SS clutch, except the ring was too big so the pressure plate wouldnt securely attach to the throw out bearing.

RotorMotor

iTrader: (5)

ACT regular 4 puck VS extreem 4 puck??? they both have the same holding specs...... whats the difference

boostin13b

I think they messed up on the specs, where did you see these specs? The only diffrence between the regular and the extreme is the pressure plate, the discs are the same, the extreme pressure plate should hold more than the regular, the regular is more commonly used in the street and strip applications, if your going to go 6 or 4 puck, then you will probably want the clamping force of the extreme.

RotorMotor

iTrader: (5)

check out rx7store.net there is no distinction between the 2. im not sure shich one would be best for me... when my motor goes in it should be putting out at least 350 ftlbs.... the strength of hte pressure plate is what determines pedal feel?

boostin13b

Yeah, Jason might just have it mislisted on his sight.

ACTman

Thank you. I was getting a good laugh with all the speculation on this. On the pressure plate we start off with new Exedy stock units and totally tear them down, replace the diaphragm, do some tricks, paint it, put it together, balance it and certify it to SFI specs. The reason you will find push type aftermarket clutches for the FD to replace the superior pull type is simply because Exedy has a patent on the release bearing design. Adapting to push type avoids patent problems. Since we purchase Exedy parts to begin with we don't violate their patent.

We grind the Exedy identification off the part, not to hide the fact that it starts off as an Exedy part, but to reduce liability for Exedy since they have no control over us and therefore cannot control their risk. It's keeps the lawyers happy. To tool up for producing a pressur plate like a stock one from scratch costs $100, 000 minimum. I know because we have done it, just not for the RX7. Unless there is some huge reason to improve the design, it's just not worth the investment.

By the way, ACT is not OS Giken! Any questions?

mazdaspeed00

iTrader: (6)

thanks ACTman. i was partcially right. the clutch is created by OS Giken but then redesigned to ACT specs.

user 9348703

Damn and my thoughts of ACT just went down. Maybe I need to drive one with it sicne EXEDY is POOP!

"By the way, ACT is not OS Giken! Any questions?"

No need for me to hear that haha, I know they are FAR from different even though the best clutch only got 5 votes hehe

jspecracer7

Guess I was right...ACT clutches ARE NOT OS Giken. I've driven ONE Exedy clutch FD...it drove very similar to my friend's ACT FD....but drove nothing like my OS Giken.

RotorMotor

iTrader: (5)

please tell me which OS you are using... and how much you paid. how is pedal feel , and can you slip it at all (is it streetable)

jspecracer7

OS Giken twin plate B type. Slightly harder pedal feel than stock. EASILY streetable. I think the full OS Giken kit costs around $1500(don't quite me though...) which includes push/pull adapter, flywheel, birdcage, 2 X plates, 2 X disks, clutch cover. Rebuild kits costs ~$600.00 which includes 2 Disks, 2 plates and clutch cover bolts.

Here's a pic of the ones that originally came in my FD. As you can see...they're toast.

ronarndt

Originally posted by ACTman:
You're welcome. Also, in support of the excellent performance of the ACT Extreme that I installed along with my most recent (up to three now) engine tran$plant- I previously had a replacement stock Mazda clutch and PP installed, which lasted about 9 months, then upgraded to a Mazdaspeed PP and Ferodo disc which also lasted less than a year. The ACT Extreme handles the additional torque of my RSR stage II motor and Pettit turbo with no indication of any slippage or wear. I am able to take thousands of miles of rubber off my rear tires at a moments notice.
Ron A.

RotorMotor

iTrader: (5)

wow, this is the clutch i want ! the only downside is it costs 3X as much as the ACT....

jspecracer7

....and will last longer than ANY ACT clutch.

RotorMotor

iTrader: (5)

i think i read somewhere that the giken twin plate should support something like 700HP! i want one badly...if only it was slightly cheaper... i cant justify spending 1500 on a clutch

user 9348703

ACTS come with Flywheel and counterweight? humm

OS just isnt a pretty clutch, not bright yellow even though it will never be seen. Its the best working clutch so far........That I have experienced. I have drove their triple in my buddies GTR a while back, just the same only quite a bit tougher to push in.

I said I overhauled my OS CLUTCH a while back, but I didnt say why. Well I overhauled my engine and I was being such a baby with it, I burnt up the clutch bearing, it seazed and blamo, on the way to the shop I lost the pressure plate and diapram of course, hints I just did a complete overhaul.

OS clutches, you can always get them USED, then do the overhaul, so now you would have a BRAND NEW clutch for usage wise, for half the price.

RotorMotor

iTrader: (5)

no, the act's (no flywheel/counter weight) are in the range of $400-500.... and who out there is worried about how your clutch looks???? im definatly not!

maybe you can get them used in japan, but most likely not out here. how much would you sell a used one for if you can get your hands on it... im interested. and its 600 for the overhaul you say??

thanks heath

jspecracer7

If you get ahold of a used clutch with 2 good plates, you can just order the disks for $300 and have a "new" clutch basically.

Jason, how much are the pilot bearings? I think mine's bad now

AJatx

iTrader: (1)

You can't say the OS Giken or any of the multiple plate clutchs are apples and apples comparison to the single plate clutches like ACT or Bones.

If you see a OS Giken twin plate or Exedy triple plate clutch for say around $1500, it's not exactly triple or double the price as you may think compared to other clutches.

For example, if you buy an ACT clutch and pressure plate, that's all you get for about $500 or so.
Throw in the lightened flywheel and you're easily paying a total of $1k or so.

The multiple plate clutches come with a flywheel since the flywheel has to be manufactured in a way to hold all the clutch discs.

So if you're comparing prices for the clutches, consider also what you get in each package. If you buy Exedy, ORC, OS, etc, then all you really need is the counterweight to install the flywheel.

J

RotorMotor

iTrader: (5)

"The multiple plate clutches come with a flywheel since the flywheel has to be manufactured in a way to hold all the clutch discs" <- are you sure this is true????? im kind of skeptical of the flywheel being included.... someone want to confirm? if so what is the weight of the OS twin disk flywheel?

also, are you able to slip a twin disk any more than say an act 4puck? im thinking about if you got stuck on the highway in stop and go traffic with a 500HP FD.... id like to be able to use the car in almost any situation if need be without destroying the clutch.

heath

cloud9

iTrader: (4)

just a guess but one probably has a sprung hub while the other does not regular being sprung and the extreme not

RotorMotor

iTrader: (5)

http://www.horsepowerfreaks.com/tech...placement.html interesting info on clutches (for a supra i believe, but whatever)

and can anyone answer the q's i posted 2 posts up?

AJatx

iTrader: (1)

The flywheel IS PART of the assembly that holds the clutch together. The clutch cover and flywheel sandwich the clutch plates together. These parts are typically not interchangeable with other vendors (i.e. Vendor A's clutch discs will not fit Vendor B's flywheel and clutch assembly).

For more info on pricing and specs, do a search on google or hear for triple plate clutches. If you see a picture of the multiple plate clutch kits, you'll see that each one has a custom flywheel to accomodate the clutch disc housing.

Weight varies and you'll need to consider all clutch discs, pressure plate, flywheel, and counterweight when comparing.

You probably won't be able to slip the multiplate clutch unless you get certain clutch disc materials that allow more slipping.

Steve Kan just put the Exedy triple plate on his FD and he tells me the engagement is linear and the pressure isn't too bad. I'm told that the Exedy triple is more streetable than some of the ACT 4-puck configs out there.

Why would you have a 500hp FD in traffic??
*question is meant for thinking, not answering*
Mine is going to see more track time than street.

J