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Old 11-20-2006, 07:09 PM   #1
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I am very sorry to bring up another boring "which clutch should I get thread," but seriously, which clutch should I get? If you have a recommendation for a clutch that will hold FI power, yet feel as close to stock as possible, please advise.

7 months ago I very badly hurt my left (clutch) leg to the tune of 5 fractures, an impaction, and detached acl. I'm still recovering from the accident and 2 surgeries, and will be for a long time to come. I need a clutch that will hold power, but also not hurt my leg and knee in traffic. I want it to engage and modulate smoothly, and generally be easy enough for SWMBO to drive the car if she ever had to. I am happy to trade off light weight and shifting speed for low effort, smooth engagement, and street civility. All the high power 1.6 clutches I see are 6 pucks, and I'm not sure that fits my needs right now.

I was also thinking of a medium duty 1.8 clutch with a lightened 1.8 flywheel. My assumption is I could get it close to 1.6 mass, but have the benefit of more surface area.

Thanks
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Old 11-20-2006, 07:22 PM   #2
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I like my Spec Stage II 1.6l. Pedal effort is very similar to stock. I beleive it would be good to 239ft/lbs (at crank). I've driven ACT 1.6/1.8 setups and didn't like how heavy the pedal was.

If you can drive before you buy. Everyone will recommend something different. I'm sure someone will post after me saying the SPEC clutches are crap.
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Old 11-20-2006, 07:33 PM   #3
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I have the ACT six puck HD and it's heavy, you won't like it with that hurt leg. I like the clutch personally but only because of the in or out characteristic that it has.
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Old 11-20-2006, 10:37 PM   #4
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https://www.miataturbo.net/forums/sh...ghlight=clutch
https://www.miataturbo.net/forums/sh...ghlight=clutch
https://www.miataturbo.net/forums/sh...ghlight=clutch
https://www.miataturbo.net/forums/sh...ghlight=clutch
http://forum.miata.net/vb/showthread...ghlight=clutch
http://forum.miata.net/vb/showthread...ghlight=clutch
http://forum.miata.net/vb/showthread...ghlight=clutch
http://forum.miata.net/vb/search.php...7&pp=25&page=2
http://forum.miata.net/vb/showthread...ghlight=clutch
http://forum.miata.net/vb/search.php...7&pp=25&page=1

I bought a Spec Stage II but it's not installed yet. All my research pointed to just one thing. They're all the same. It's almost unanimous (if you're talking about the same stage), that all brands are almost identical to pedal feel, performance, and longevity. In my months of searching I couldn't find one person who said that X clutch is better than Y clutch and gave a reason. People would say they liked the clutch they bought, but few had driven multiple brands and could give accurate data over an extended period of time why one was better than the other.

My advice, stick with the name brands, ACT, Exedy, RPS, Spec, you can't go wrong no matter what. I bought from the link below, and it was absolutely the cheapest price I found on a Stage II from any brand. If you know where to get a 240ftlb Stage II from a name brand company for less than $310 shipped, let the rest of us know. I have heard that the Spec clutches have slightly less pedal effort than the others, and that the ACT's seem to be more "reliable", and the Exedy StageI is very inexpensive.

Your idea of going 1.8 is very credible to get a little more clamping power... if you can get the 1.8 fly down to 1.6 weight... I don't know what the difference is, but it shouldn't be to hard. People say you can have them shaved for about $50, but you're paying a guy his hourly wage to stand in front of the lathe and slowly turn the dial.

If you can wait two weeks, I'll be installing my SpecII the weekend of the second and should be able to give a good review later that week.

http://www.jdsperformance.com/spec.a...iata&fcmd=cars
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Old 11-20-2006, 10:40 PM   #5
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The PO of my car put in a Max-5 clutch from PBC about 5k miles before I bought mine. Having driven Miata's with stock clutches, you can hardly tell a difference. I'm not sure if you can still get it, though, as PBC is getting out of the parts supply business. I do like the clutch though.
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Old 11-20-2006, 11:04 PM   #6
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what's the real difference between a 4-puck and 6-puck. I'm thinking of just buying a new disc one the cheap so I can hold more boost. My HD doesn't like 12psi, it's just a OEM Exedy disc. The Performance street holds a bit more, but the 4 and 6-puck will hold 70 more tq with the same plate. I dunno which I should go for.
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Old 11-20-2006, 11:17 PM   #7
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What? Not all clutches are the same. Not in holding power, pedal effort and trype of engagement. Type of disk an construction of pressure plate can make a dramatic difference. Takes about 2sec to tell the difference betweem my Spec II and an ACT HD.

I think the 4-puck will have a much harsher engagement. More on/off, and little ability to slip. Expect more clutch shudder and drivetrain vibration as you engage the clutch. The 6 puck will be a little more forgiving I would expect. Either way the 4/6 puck is going to be way less friendly on a daily driver than a more traditional clutch.

Jay
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Old 11-20-2006, 11:24 PM   #8
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I'm going with the 1.8 clutch and flywheel.

In Aus, we had a special edition 2002 MX5 built by Mazda Australia, called the SP. It is the most powerful factory MX5/Miata/Roadster produced, with about 30-40HP more ATW than the Mazdaspeed miata (which we called the MX5 SE).

The SP has standard clutch and flywheel, and deals with the power very well, and (obviously) has stock feel. These can be picked up quite cheaply second hand too. And i would only lighten the flywheel if you plan for it to be used with a N/A engine. The turbo will deal with the extra weight, and you'll have more torque up the hills.

Just my opinion. Hope that helps!
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Old 11-20-2006, 11:51 PM   #9
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ever drive on the street? dont even LOOK at a puck clutch. they hold more power because they have a higher static coefficient of friction. BUT... they dont slip. the go from not-engaged to GRABBING. slipping them will wear them out super fast. been there and god damn done that. sucked *****.

I think the only difference between number of pucks (6, 4, 3, etc) is rotating mass and engagement. If you do the math, surface area doesn't factor in to holding power given a fixed clamp force and friction coefficient. That said, I think as you engage a 6 puck versus 4 puck it will be smoother since the load is spread out over the whole disk. but once it's clamped down it's the same.

NOW to answer the original question.... there's only one way to hold more power and have a light pedal without shitty engagement. add disks. I run a twin plate myself for that reason. I chose the second lightest spring which claims to hold 480 ft-lbs. It's probably about "stage 2" stiff at the pedal, maybe a little more. they make an even lighter one that holds more like 250 ft-lbs which I imagine will have a SUPER light pedal.

If you dont mind the extra work involved, it's a different way to go.

Matt
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Old 11-21-2006, 12:34 AM   #10
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Quote:
Originally Posted by braineack View Post
what's the real difference between a 4-puck and 6-puck. I'm thinking of just buying a new disc one the cheap so I can hold more boost. My HD doesn't like 12psi, it's just a OEM Exedy disc. The Performance street holds a bit more, but the 4 and 6-puck will hold 70 more tq with the same plate. I dunno which I should go for.
Jay nailed this one, but I wanted to add in that if you order a puck clutch, you need to order a torsen too. The puck clutches are digital in engagement. It can be unforgiving for passengers and driveline.

Ben
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Old 11-21-2006, 12:42 AM   #11
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Jay and Sam: thanks for the heads up on Spec. That will go on the short list. The stage I 1.8 with shaved flywheel or 1.6 stage II may be the way to go. I'm curious about differences in smoothness, engagement, and life span between those.

Matt: Can you point me towards a twin plate clutch? 250 ctq and a light pedal sounds perfect (also assuming nice progressive non digital engagement).

I'm also going to see if anyone is parting a MSM.

Ben
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Old 11-21-2006, 12:58 AM   #12
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I always thought the big deal with the multi disk clutch setups was the size and weight of the package. Aren't some like 5.5" in diameter?

Disk material (carbon, kevlar, iron, organic) and configuration will add to the max amount the clutch will hold.

Kevlar in the SPEC stage 2 disk has very good holding properties, but starts to let go a little when REALLY hot. Some drag racers have said that after going multiple hard launches that the clutch gets a little soft. On the upside to that Kevlar is supposed to have a very long life.

If you want a very easy to drive clutch with good solid performance the 1.6 SPEC Stage 2 is excellent. The only reason I can see to go to the 1.8 size in the SPEC lineup is to go after the Stage 2+.

Jay
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Old 11-21-2006, 08:44 AM   #13
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Quote:
Originally Posted by y8s View Post
NOW to answer the original question.... there's only one way to hold more power and have a light pedal without shitty engagement. add disks. I run a twin plate myself for that reason. I chose the second lightest spring which claims to hold 480 ft-lbs. It's probably about "stage 2" stiff at the pedal, maybe a little more. they make an even lighter one that holds more like 250 ft-lbs which I imagine will have a SUPER light pedal.

Matt
Matt,
You're forgetting two things about having light engagement and good power holding. Pivot point and material. The original FM Clutchmasters kevlar was very stock like and held 240 ft lbs in my '90. Clutchmasters moves the pivot point on the pressure plate fingers to get more clamping force. ACT on the other hand just puts in stiffer fingers on the pressure plate that they rate at lbs.

FM got away from Clutchmasters because of quality control. The ones that held up (mine) were great. It had worlds better feel than the ACT. I've got a heavy PP in my Forester XT and wish I had something closer to stock. I've been test driving 99 Miatas and it's crazy how light the clutch pedals are.

All my rambling aside, the SPEC II seems to be the best high hp, low pedal pressure choice available. If anyone carries the Clutchmasters you should check that out too.

Frank
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Old 11-21-2006, 08:57 AM   #14
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I'm running a 1.8 6 puck in an RPS Sport on a 1.8 flywheel. I did this to get less pedal pressure and good holding. After 33K miles, I am still happy. The engagement is a little faster than stock and takes some getting used to, but I have no problems in stop and go traffic and don't find it a strictly on/off arrangement.
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Old 11-21-2006, 01:06 PM   #15
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Frank:
Changing the pivot point changes how much pedal travel you need. It's a simple lever right? If you want to lift the fatter kid on the teeter totter, move the pivot but you gotta move further. The distance the pedal (master / slave system) can travel is a fixed value. I believe a lot of the problems of the clutches out there is that they work best beyond the existing limitation and you end up with your clutch engaging on the floor.

My tilton twin plate actually has two pivot point options. You can get pressure plates with different ratios. one holds more power slightly but requires more travel and is lighter to press.

As far as kevlar vs. carbon vs. organic.... kevlar is most durable but holds the least power. I'm not sure how carbon stacks up. I think organic would have the best engagement properties. I might actually try a kevlar disk to improve service life of my setup. The twin plate setup I use is very sensitive to disk wear--you can't run a disk down to the rivets and still hold power.

jayc72: yes it's for total weight too. it's the same benefit really. If you want to hold the same power with a smaller clutch, you can use two disks. the clamping force is the same, but the torque capacity doubles. I have plenty of weight reduction as it is--the whole clutch-flywheel assembly is something like 17 lbs.

Ben: no, I can't point you to a link. It's custom. I may do a writeup some day though. it's basically fidanza's 7.25" clutch flywheel and tilton's cerametallic rallye style twin plate clutch with some 7.25" organic disks from clutchnet that I had custom made. the other two parts are a 7/16" longer slave push rod and a 7/16" shorter fork pivot. Both are pretty easy to make. Another option is a 7/16" tranny spacer (yuck for all that entails).

Total cost is reasonable... ROUGHLY $400 flywheel, $350 clutch, $160 disks, $25 misc hardware. That's pretty damn reasonable for any clutch/flywheel right?

Matt
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Old 11-22-2006, 08:35 AM   #16
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Quote:
Originally Posted by y8s View Post
Frank:
Changing the pivot point changes how much pedal travel you need. It's a simple lever right? If you want to lift the fatter kid on the teeter totter, move the pivot but you gotta move further. The distance the pedal (master / slave system) can travel is a fixed value. I believe a lot of the problems of the clutches out there is that they work best beyond the existing limitation and you end up with your clutch engaging on the floor.
Matt,
Were you agreeing or disagreeing with me? My Clutchmasters kevlar was much easier to adjust in my '90 than my ACTs were. It had a longer engagement period (not as on/off as the ACT) but that didn't seem to affect the master/slave at all. In fact they were never changed and the car had 140K on it, 10K with the CM clutch, another 5k with the ACT.

Frank
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Old 11-22-2006, 02:06 PM   #17
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Quote:
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Matt,
Were you agreeing or disagreeing with me? My Clutchmasters kevlar was much easier to adjust in my '90 than my ACTs were. It had a longer engagement period (not as on/off as the ACT) but that didn't seem to affect the master/slave at all. In fact they were never changed and the car had 140K on it, 10K with the CM clutch, another 5k with the ACT.

Frank
Yes.

I was sayin that I wasn't a fan of the modified pivot on the majority of aftermarket clutches. I ran an ACT in my All-trac and I hated it. The engagement point was so low I think it killed my synchros. That soured me on ACT.
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Old 11-22-2006, 11:13 PM   #18
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I stick Clutchnet clutches in everything I build. I have been pretty happy for the most part. I have used the Red Pressure Plate in a Miata and the pedal still feels like stock. www.clutchnet.com The Carbon pro with yellow pressure plate is a great combo as well. I have an account with them as well so figure %10 off the webiste is what I can get you the clutch for.
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