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I had one of these in my '91 MR2 turbo. I was pumping out 575 hp at the crank and pushing 24 psi out of the turbo. It was a nice setup and I needed a clutch that could grip it all. Anyway for those of us who are considering the turbo for the 8 will benefit from a clutch that will grip to 9k+ rpms with the turbo adding extra pressure on the plate. I am excited... Here the e-mail:
Dear Mr. Tim Loe,
Thank you for your inquiry regarding our quality products! We are currently developing a clutch assembly for the RX-8. We do not have a release date at this time, but we typically allow three to four months of development time. If we happen to have the assembly come in ahead of schedule, we will post the press release on the website. Thanks again for choosing Centerforce!
A Div. of Midway Ind.
928/771-8422 x36 firstname.lastname@example.org
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It's a clutch that grips about 90% better than stock clutches on most cars. For those of us looking to increase the power output by 50 hp or more this is a necessary step. We will get to a point where the stock clutch just can't grip any more especially when we turbo the car.
Let me explain why. When you get sudden increases in torque those pressures pull on the clutch plates causing them to be more likely to slip. These increases in torque can be due to forced induction, ECU re-mapping at higher rpms, nitrous, and anything else we do that gives sudden increases. As the rpms rise the ability for the clutch to grip decreases. Now add to this additional torque and the problem gets worse. Centerforce has developed a clutch system that uses weights to hold the clutch in place even at higher rpms. Because of the weights the clutch will actually grip harder at the higher rpms. This is due to centrifigul force. And this is a good thing when you are trying to put high hp and torque to the ground.
On my MR2 while I was getting the hp up to the 275 range I burned out my stock clutch. I replaced it with stock and burned out the 2nd one within 15k miles. After I put in the Centerforce clutch I upgraded to around 375 hp in the next year, 475 hp the following year, and 575 hp the last year I had the car. I never felt the clutch slip. Centerforce makes clutches for drag cars with over 1k hp. They are very impressive. This was money well spent when it came to getting my hp to the ground.
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Last edited by 93rdcurrent; 02-17-2004 at 01:43 PM.
I'm not a big fan of the Centerforce DF. Had one on my FC, installed and broken in properly, and it couldn't hold the power - about 250 to the ground with the mods at that time.
Some people have had good luck with them, some haven't. Personally I think the weights on the pressure plate is a bunch of marketing BS.
If you want a good clutch, get an ACT. No frills, they work like a champ and clamp down like a rabid pit bull. You can everything from a very streetable clutch to a very heavy puck clutch. And, they're priced reasonably.
Again, I've seen people that have had great luck with the CFDF clutch, and I've seen plenty that haven't. NO ONE with an ACT clutch has had a problem.
ACT is almost done with their RX-8 light flywheel, and I imagine a clutch won't be far off in the future.
RX-7 Bad Ass
'94 RX-7 R2 Brilliant Black - building the perfect FD
I agree that ACT has a great clutch and I have heard from people that they were happy with them. I reall liked my Centerforce df clutch and the only problems I have heard of were from people who didn't balance it right. With the weights you have to make sure they are properly balanced so no discount transmission shop installs unless the tech knows what they are doing.
The weights don't need to be balanced - they self-center themselves, and can move around. At least that's true on the 2nd gen RX-7 application. Heck, the 3rd gen CFDF clutch doesn't have the weights - there's no room for it with the pull-type clutch on the 3rd gen.
Again, I really don't think the weights even do anything - I think it's just marketing hype. And you're paying quite a bit for that.
All I know is I was happy the day I hucked mine in the trash .
RX-7 Bad Ass
'94 RX-7 R2 Brilliant Black - building the perfect FD
Originally posted by 93rdcurrent As the rpms rise the ability for the clutch to grip decreases.
Incorrect. Revs has nothing to do with the grip of a clutch. Nothing.
Originally posted by 93rdcurrent Now add to this additional torque and the problem gets worse.
Ummm, the only problem is torque!
A couple of other notes:
The OEM clutch is designed to have a decent safety factor for torque capacity. I doubt anyone will develop a N/A 2 rotor Renesis within the next year or two that will overpower the OEM clutch. A 1.8L Miata clutch is good for a reliable 170 lbs-ft. The RX-8 clutch is probably bigger. I bet it will be good for ~200 lbs-ft. which equates to about ~293 hp (crank) with the same shaped power band as the 6 port Renesis.
There are some issues with the ACT brand clutch being noisy during shifts on Miatas and some other vehicles. The noise is a squeal that is not pleasant to the ears. Some people have it while others don't. There is no resolution to the issue yet but hopefully one will be found. This noise may appear on RX-8 clutches also. Who knows?
Going from the OEM clutch will affect pedal travel significantly and where the clutch fully releases. Some people do not mind this while it bothers others.
The Centerforce clutch for the 1.8L Miata does not use weights due to clearance issues. Since the RX-8 uses the same tranny I bet that Centerforce will not be able to use weights for this application.
Basically, there are several detriments to installing an after market clutch. I also seriously doubt that there are any N/A RX-8's that need a clutch upgrade. I think for these cases the OEM is the best bet and it happens to be free. All bets are off if we are talking turbos, supercharges, N2O or extra rotors.
We'll just have to see. I am not going to replace mine until it starts slipping but I will be looking to get 330 hp by next year. Mine won't be N/A however... This is why I am excited about a clutch I have already had good experiences with at hp levels I won't take my RX-8 to. This means I can expect a long and healthy life out of my clutch.
And I personally enjoy having the clutch engage closer to the floor. I know how to drive it that way and it helps keep me from riding the clutch when I am pushing the car hard at the same time I am shifting. And that is exactly what I got out of my CF DF clutch in my MR2.
When I am heel and toeing it I find that with the stock clutch it is harder to feel where it begins to engage than with my CF DF clutch on my MR2. This means that at higher rpms I am more likely to burn out my clutch and that is what I was referring to. When I re-read my post I could see exactly why it seemed like I was speaking of the rpms causing the clutch to seperate. It is the torque you are right.
I have had great success with the CF DF and I would recommend it. Like I said above I would also recommend that a reputable shop who know what they are doing with aftermarket performance equipment do the installation. It's not rocket science but it isn't for the novice either.
BTW, if you are in Houston, The Tire Man (Washington Ave.) will do a rwd clutch job for $220 labor. I found this out because I have a buddy that we will be putting a blower on his Miata this coming weekend and I was dreading burning a weekend doing a clutch job.