I'm happy with my ACT HD clutch. I'd look at their Xtreme pressure plate or the Exedy clutch kits if I was making more power (about 320 whp now with street port, bolt-ons and tuning).

 

Exedy Twin Plate on a sub 400HP street car is complete overkill. Expensive and chatters like crazy.
ACT HD is plenty.

 

Are other people getting chatter on the Exedy twin plate clutches?

I haven't yet. So far it is quiet and smooth on take off.

Only downsides I have noticed is price, easier to stall than full face disk and can engage so hard as to be abusive to the drivetrain if you let off the clutch too fast (whack).

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I did get chatter on my Indigo flywheel/ACT HD PP when I first changed it out from full face to the sprung 6 puck.

That single 6 puck set-up would often judder on taking off gently from a stop until it was worn in.
Maybe it had to wear off the transfer material from the full face disk or maybe it had to wear the flywheel surface flat (it does *look* unevenly worn now).

It really didn't sort itself out until I started drag racing as well as auto-x.

 

Tom, as you know, I've run the ACT Street/Strip clutch now for more than 10 years with no issues. Granted, I do very few hard launches and most of my driving is spririted roll-on WOT, but again, mine has held up very well.

 

^This and with an 11 lb. flywheel. ACT SS disc and PP is probably 12+ years old. But full disclosure, I'm probably only at about 350 crank...maybe 300 whp.

 

This is the setup that I used for several years, and it generally had good manners. That being said, I agree with BLUE TII that it won't hold up to real abuse; at least not if you're in the 400+ range--in my own experience.

If you drive it nice you'll be okay, but the problem I had was with flat/full throttle shifts. If the tires would bite on the shift, the clutch would slip big-time. This occurred frequently; especially on roads with an uphill grade, e.g., freeway entrance ramps, which we have a lot of around here. (Note that said ramps are a requisite part of an FD's proper presentation.)

Upon the experienced recommendation of another longstanding forum member, I replaced the disk with a sprung 6-puck.

Insofar as the heavy -XT pressure plate is concerned, I reinforced a stock clutch fork (to prevent breakage) and put a roller bearing in the clutch pedal arm (to improve clutch articulation & drive-ability) and have not experienced any problems with this setup whatsoever over the last 14yrs and 80k+ mi. of heavy duty use. (There are old threads that detail each of these mods.) Note that if you do a lot of stop & go driving in traffic, the heavy -XT plate can get tiring; I frequently did hours on the infamous 405 in LA.

I am now experimenting with different clutch master/slave ratios as a means of mitigating the heavy -XT PP since the 6-puck disc doesn't need as much travel as a traditional full face disc.

 

No chatter of any kind. A slight rattle when the clutch pedal is depressed (clutch disengaged), but that is to be expected when there are free floating parts. Staggering the clutch disks virtually eliminates the rattle.

 

I highly suggest you stay away from Spec. I've had quite a few fail, even one on my own personal car which was their stage 3 6 puck.

I like the ACT ZX6-XTSS and Exedy twin ZM022SD. Make sure that you use the Monolock collar from ACT on either clutch kit!

Also I do not have any personal experience with them (ordered but not installed) but I know Len Bacon was a big fan of his OS Giken clutch. They are pricey but I've never heard anything bad about them. I can give you a quick run down of clamping force for each type of clutch from them.

As far as "drive-ability" for a daily, that is all personal preference. Everyone is different. Both of those clutches will increase pedal effort.

Mike

 

Could you post the OS Giken info? Do they list clamping force or torque holding ability?

 

For me drive-ability is entirely how much it can slip before it bites. I don't care if it feels like one-legged body weight squats as long as I can slip it a little so I don't chirp tires trying to pull into my garage.

Thanks for all the suggestions everybody.

 

They do not make those figures public. Also as a vendor they give us "ball park" numbers for their different clutches. Most are under rated.

Mike

 

That right there is the key. I get no rattle except for initial start up and goes away.

 

I would like to hear more experiences with the ACT ZX6-XTSS. I know its stiff, and will need the newer re-inforced clutch fork. For people not looking to spend $1.5-$2k for a clutch I see this as the next best step.

BTW my DD E39 M5's OEM clutch is stiffer than my ACT HD/SS. Unless the XT is stupid stiff, I dont see it being an issue for any car enthusiast not DD their FD.

 

The route I am going is the FC XT pressure plate with the Turblown push conversion. About the same total cost in the end as a cheap twin plate, but if the ss clutch disk works well, and the pedal feel is what I am hoping it will be... then the benefit will be maintenance will be much cheaper, and future replacements/upgrades are also cheaper.

 

I have a ACT SS/HD and a lightweight flywheel that works fine with the twins. I don't do any drag launches and I drive pretty easy on the clutch, but suspect that wont be enough with my upcoming EFR 8374 upgrade. If I wanted to go on the cheap could I just throw a 6 puck sprung disk in there and call it a day? My setup is pretty low mileage so the flywheel and bearings should okay.

If I have to tear everything down anyway I may just get the exedy twin plate which doesn't get a lot of complaints, but this build is getting kinda pricey as it is.

 

I know the Exedy Twin has been pretty popular, I've been running the Exedy Hyper Single which came with a lightened flywheel. Put about 9k miles so far and it's been smooth with no chatter/rattle and has held firm with 418 rwhp.