bbundy

I tried a spec stage 3+, Initially with an aluminum pressure plate. It chattered like crazy making it just silly to try and launch or drive around town the aluminum pressure plate didn’t handle the heat and it wore out quickly. They replaced it with a non aluminum one and it still chattered like crazy then started slipping badly. The Spec stage 3 is rated at 300 ft-lbs the 3+ like I had was rated at 400 ft-lbs torque capacity, they must rate them in a perfect world. The ACT 1.6L extreme ZM1-XTG6 that I have now is rated at 353 ft-lbs. I ran a 1.8l ACT HDSS rated at 233 ft-lbs and it didn’t slip as badly as the 400 ft-lb rated Spec.

Thanks to the wonderful customer service from Emilio at 949 I got my money back from the Spec ordeal.

If I was to do the ACT again I might try an un-sprung hub to save a bit more weight and I am not convenced the springs help save the driveline that much. When the coil springs bottom out hard it seems like it is more like an impact hammer than not having them at all.

Bob

y8s

iTrader: (8)

what difference does it make? it's done both. ask tilton?

here's the thing: the disk makes the drivability.

organic disks are easy to modulate
ceramic/cerametallic do not modulate even if you hook them up with your hot sister.

I ran twin organic disks -- maybe good for, i dunno, 350-400 ft lbs? and they were virtually indistinguishable from stock except for the superfast revving of the motor and mild rattle with the clutch pedal pressed.

Here's the specs:
http://gallery.y8s.com/miata/tilton

I put this together several years ago when nobody made a kit and total cost was under 1200 I believe. Actually a little less with the organic disks.

as a testament to its awesomeness, my sexy wife could drive the car unsupervised with the organic disks.

the biggest issue is that the lack of thermal mass means it has a hard time dealing with daily stop and go traffic and eventually the floater plate warps and makes it hard to disengage. it averages about 2 years for my commute but on a track your clutch use is so transient and less slip-dependent that it could last much longer.

I loved the cerametallic disks on the track except the one time I downshifted and let the clutch out too fast and chirped the rear tires somewhat late into a corner. Never tried the organics on track.

y8s

iTrader: (8)

been running unsprung hubs on the twin plate for YEAAARRS on my turbo car and I'm still on my original trans. I have done plenty of hard launches on it and it still shifts like butter at 100k miles. even a few tens of thousands of miles on ceramic disks with unsprung hubs. tell me that's not going to test a transmission.

scottyd

You're kidding right?

It makes all of the difference. Sav's car is awful to drive around the block(DD status). Jerky, hard to launch, etc. On the track though, you can't love it enough. The setup loves to be driven hard.

Absolutely. You've got an organic (easier) and you have a very mild PP.

y8s

iTrader: (8)

I drove the twin cerametallic disks for >10,000 miles on the street. I'm intimately familiar with crying myself to sleep after a two hour drive in traffic on my commute.

But they are no worse than a single cerametallic disk in a miata-specific clutch from any other vendor. That was the point I was trying to make.

The organic disks are still solid performers. I just never tracked them so I can't say if they're as robust, but I imagine they are since 90% (wild guess) of people are running an organic disk on the track in a miata.

Key point: all a twin disk does is double your torque capacity without affecting your clamping force.

or conversely: it allows you to halve your clamping force while maintaining your torque capcity.

or even reduce clamping force and increase torque capacity.

given similar materials, it has no effect on drivability compared to a single disk.

scottyd

Don't you have a sexy wife to console you?

FatKao

949 organic twin is sex. Put it in my N/A track car. It's rough for getting around the paddock but it's fun challenging people to get the car in gear with 1 try.

hustler

iTrader: (6)

You're a ******* retard and troglodytes like yourself are taxing this forum. Are there any other opinions you hold on things you know nothing about that you'd like to share...possibly the female body or maybe books in general?

y8s

iTrader: (8)

once I put in the organic disks, i had more ladies than passenger seats.

hustler

iTrader: (6)

Strange, I would not expect that. Many of my friend's have terrible pedal engagement with the ACT on their Miatas and I put one in my Jetta years ago that never worked and I never got my money back...I was not happy and am still not happy. After the rivets broke off the disc, I swapped to another brand and never had a clutch that hooked-up properly. I also don't like how the ACT clutch is $600 god damn dollars.

Mine doesn't chatter bad but I can only launch it in first, it will chatter to bad to launch in 2nd...but I never, ever, ever, ever launch it. I broke my clutch in with 86whp for a few thousand miles so maybe that is the difference.

hustler

iTrader: (6)

I have no problems operating that clutch, I'd daily it if I were baller.

Godless Commie

iTrader: (2)

I went with Spec stage 2.5. One side is carbon fiber, other side is cerametallic.
Very smooth even in the worst traffic, and hard launches are no problem, at all.

I also run 225/40/16 T1Rs, and about 225 to 230 whp.


(edit: typing is a bitch when th batteies in the wirless keyboard tae a crap)

bbundy

The pedal effort was and the engagement point were the only things that worked good on the Spec 3+ for me. ACT generally has a heavy pedal and requires a lot of stroke to actuate moving the engagement point near the floor, other than that it is a rock solid performer and you get use to the pedal.

I will probably get a twin some day but rught now XIDA, OS-Giken, V8-roster A-arms, are all higher on the big ticket items want list.

Bob

92dx

iTrader: (2)

I use an ACT klde v6 clutch kit--organic disc and HD pressure plate. Rated 285 ft/lbs. (per ACT website) Im pushing ~220 through it. Nice pedal feel and grips hard.

ZX-Tex

iTrader: (15)

That is not my experience. My ACT XTSS is great, track or street. That is an 'extreme' pressure plate with a sprung organic disc. Rated for 300+ ft-lbs. Adjusting the clutch a bit (under the dash) helps with the near-floor engagement, not a big deal, easy to do.

Savington

iTrader: (31)

+1. The rental's ACT HD engaged on the floor, a quick adjustment of the pedal and it was back to stock again. I wonder whether the XT is worse, or whether there are a lot of whiners out there who don't know about the pedal adjuster.

rharris19

iTrader: (41)

Same here. My ACT XTSS was awesome and absolutely loved it. Once I adjusted it, I never had to touch it again.

bbundy

I've had both XT's and HD's they all required a bit of pedal adjustment. Don’t notice much difference between the two. ACT tends to require more stroke than other brands between free play position and disengaged position. Doesn’t seem to make them more difficult to operate performance wise in my opinion. They hold torque and engage nicely even the puck ones arent that bad.

Using 1.6l size clutch saves considerable rotating weight and lowers MOI even more.

Bob

Braineack

iTrader: (62)

It's this. they don't understand leverages. the ACT alters the angles to make pressing a heavier plate easier.

hustler

iTrader: (6)

I know of two local Miatas with the adjuster all the way out (moves the pedal forwad) and you have to mash the pedal into the carpet to make it disengage. That's not something I'm willing to deal with and ACT is such a heap of **** company that I don't care to fight with them on the phone again.