Contour Enthusiasts Group Archives Forums Modifications Transaxle Clutch for 350-400hp/tq... rate em

Now that the SPEC Stage 3 is being used by quite a few more, is the chatter an issue?

I came close to buying a spec stage 3, logged into NECO today (for the first time in months) only to find quite a few are now complaining about the chatter of the spec stage 3

I need a clutch, on a 100 shot and my 3l i melted my centerforce dual friction... so it needs to be strong... at this point, i would rather sacrifice driveability than to have a chattering clutch...

anyone have thoughts on which clutch... clutchmasters/competition/act ?

I don't think you can get the best of both worlds when you're dealing with torque loads that high AND when the size of the clutch disk is fixed...or limited by the bellhousing size.

The only option I can think of is asking for some company like spec to make a custom clutch setup that uses a pair of stacked clutch disks with a steel intermediate friction plate.
These are out there for high torque Hondas and other cars where there just isn't enough clutch material available in a single disk to hold the torque.
Anyway, with a dual disk design you should be able to use a more normal, softer engaging friction surface with a sprung hub and a pressure plate that would use a little more pedal travel for engagement. One disadvantage would be more mass being turned by the engine that would slow down the engines ability to rev as quick, but it may be negligible since a duratec can be made to reve so quickly anyway. A Fidanze is light enough to offset the change in mass anyway.

The spec3 has very little pedal travel from fully disengaged to fully engaged, making it very sensitive for one. There is a sweetspot though once you start driving it and you get used to it.
The chatter seems to be a bit of a hit and miss though it will always crop up once in a while when taking off from a turn especially when the engine/trans/clutch is good and warm. Some get it worse than others. This last disk of mine was a lot smoother than the first spec stage 3 that I bought and all I did was swap out the disk with a brand new on, same pressure plate.

Anyway, to anwer your question, the spec stage2 is supposed to hold that torque and be quite smooth. I am not convinced that Kevlar clutch disks are [censored], so I would still consider it an option.
The stage1+ would be on the borderline,
And of course we know the stage 3 and greater can hold 400 ft-lbs or more. I know mine has never slipped when I haven't rested my foot on the pedal.

I've broken in my stage III, and I love this clutch! I don't hear any chatter, but that could change with time I guess. Not harsh at all IMO, and it bites great!

When I was having custom ceramic hybrid clutches built by a huge local clutch company, they told me about their dealings with kevlar. From their experiance, kevlar is good for not biting into your PP and FW so that you're able to simply replace just the disk without any machine work (Like semi-trucks, who want as little down time as possible...) quite a few times. I would think from that data, that it really isn't a great performance type lining.
The oil issue (kevlar glazes over when contaminated with any oil product) has been a factor in our platform, and many CEG'ers have run into this after I voiced what I'd learned.

I cooked a Centerforce DF clutch in my Eclipse GSX within 1000 miles after a good solid break in. I replaced it with a stage 2 or 3 ACT clutch and it took a flat out beating and lasted 10K+, up until I sold the car. ACT's rock!

Interestingly enough, spec now as a Stage 3+ for our cars.

From the SPEC website about the Stage 3+:

Quote:

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Stage 3+
Features a streetable high clamp pressure plate and full face carbon semi-metallic disc. Listed as an upgrade to the stage 3, it offers torque capacities more comparable to the stage 5 but with drivability equal to, and in some cases better than, the stage 3. The high capacity and excellent drivability characteristics of this clutch is a result of years of research and development for this SPEC exclusive disc compound.

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Kinda hard to believe, a 540 tq rating with driveability to a stage 3 or lighter. Does anyone have more info on this clutch?

Also concerning SPEC chatter, I read a post on NECO that mentioned, using a stock throw-out bearing instead of the SPEC supplied one, gets rid of the chatter. Any truth and weight to this statement?

The chatter is from the stronger pressure plate. (It is magnified if you use a lightened flywheel) It's a small price to pay for that upgrade though.

I am not sure if there is something wrong with my Spec III or not. BUT i can make it not chatter. When i let the pedal out really slow while in neutral...when the cltuch if fully disengaged it does not chatter. If i let the cltuch out normal(fast) it will chatter.

Plus...the chatter is a small price for me to pay to have a good grabbing clutch that won't fall apart like my stock one did.

For me it is still a Heat affected phenomenon that has some influence form the limited slip differential.

Hotter operating temps makes it more likely, hotter temps AND taking off when the diff is biasing makes it even more likely.
Slipping it slowly helps.