Drivability of solid center, un-sprung clutch disks?
 

Im ready to order my clutch for my car, and Im not really sure what to get. With planning on making ~400 RWHP, I think a puck clutch is pretty much essential. However, I really dont want to make it a chore to drive on the street. Id like to get a 6-puck disk with a sprung center. The only one I can find is from a company called " XTD " , and they seem to sell exclusively on Ebay. I dont believe ACT makes a 6-puck with a sprung center. How bad is pulling out with an un-sprung clutch disk? Id imagine it would be very harsh. I will also be using an aluminum flywheel. I think I may give the XTD brand a shot, but Id really like to go with a name I trust, such as ACT.

My friend has an ACT 6-puck unsprung disc on his modded SR20DET'd 240sx, and let me tell you it is NOT fun. The whole car shudders pretty violently every time he engages the clutch from a stop.

on a side note, after riding in his car I'm selling a brand new unused ACT 6 puck unsprung disc for an SR20DET I was gonna use on my 240....

I'll throw my experience and knowledge in here...I've installed and driven a LOT of clutch setups on all teh various customers cars as well as my own.

Your ability to hold power/torque is mainly affected by the pressure plate's clamping force. The stocker clamps a certain amount, most aftermarket versions (upgrades, not stock-type autozone replacements) clamp more. This allows you to hold more torque/power, but it also increases pedal effort in most cases.

The disc itself determines engagement characteristics. Regular discs are called organic, they're a softer fibrous material, and combined with the sprung hub they engage quietly and chatter-free if you know how to drive and your flywheel/pp surfaces are in good shape. Puck clutches grab much harder...in general, the fewer pucks, the harder they grab, and the less street friendly they are. Puck clutches are basically pads of copper and/or other metals...think of the clutch system as a reversed disc brake system...instead of 2 softer pads gripping a metal disc, 2 hard discs are gripping a softer disc. Just as with brakes, the harder the pads (clutch disc) the more grab you get, but the more abrupt the transition becomes and the more wear you cause to the other surfaces involved (metal clutch discs wear the hell out of flywheel and PP surfaces). Also, sprung vs. unsprung is a consideration...most all puck discs are unspring, also called solid, further adding to the shock when applied.

With this knowledge in hand, you can mix and match a PP's and clutch discs to suit your needs. For instance, ACT makes 3 discs for most applications, and 2 PP's. They offer a standard organic which is not any different from a stock organic disc, and they make 6 and 4 puck solid discs. They also offer heavy duty pressureplates good to around 350 ft-lb I think, and extreme pressureplates good to 450 or more. Remember, the stronger plate also has much heavier pedal feel...it requires more leg power to push and hold.

My recommendation if you want to street drive your car daily but need power holding is to go with an organic disc and a strong plate. IF you race quite often, from standing starts, you'll want a disc that bites harder, like a 6 puck. If your car is race only, you'd want something like a 4 puck.

I currently run a modded turbo engine and a nonturbo drivetrain in my (heavy) convertible. I'm at a disadvantage because of this, compared to a stock t2 drivetrain. Not only is that drivetrain stronger, but the clutch holds more power due to larger diameter (larger diameter = more leverage = more capacity). Because of this, I went with an act extreme PP and a 6 puck disc. I've installed and driven 6 pucks before, but not in conjunction with the heavy extreme PP. Between the abrupt bite of the 6 puck causing chatter and shaking of the car violently (you look like a jackass at redlights) and the very heavy pedal effort required to operate the plate, it's not a good combo for the street. I knew this when I installed it, but I'm on a different engine setup than I originall planned, and my power goals have changed, so I'm strongly considering a milder clutch setup, at least an organic disc.

Another thing to consider, aftermarket flywheels (lightweight) reduce rotating inertia, and along with it they reduce the amount of available torque just off idle to pull out with. So, versus a stock flywheel'd car, it'll be harder to take off, even with a stock clutch. Couple that with a harsher clutch, and you can make your life unbearable quickly. For the light flywheel, I do not recommend a puck disc, unless your car is for race only, or at least more race than street.

I've ridden with a friend who has a 6 puck unsprung ACT clutch disc and pressure plate in his TII. He has gotten use to driving it as a daily driver but he said it took patients and practice. Its a neck breaking launch if you rev it up and drop the clutch.

Thanks for the input. This is the clutch setup that I was looking at trying out :

http://cgi.ebay.com/ebaymotors/ws/eB...category=33730

Any input on that? I would like a 6-puck (car is more of a weekend car than a daily driver) and I would think the sprung center would take some of the harshness from the engagement.

get the spec stageII clutch. i have one in my TII and i was running high 12's dropping the hammer from 6500rpms at the track on the launch. SPEC is a cool company, relatively new infact.
but their stage 1 is an organic disc holds like 300tq,
stage2 is a kevar disc that holds 380tq,
stage3 is a sprung hub 4puck that supposedly holds like 410 tq.

all the spec clutches that i've felt have had a relatively LIGHT pedal pressure, but seem to hold all the torque that they are rated for. i HIGHLY recommend the spec stageII or the stage3 if you need a little more holding power.

I've driven an ACT-6 quite a bit and it took a couple minutes to get used to it but its realy not as bad as everyone is making it out to be, i like the feel of a grabby clutch.

If you go with a spec make sure its AT LEAST stage 3, stage 2's have been known to get very tired very quickly if used under any sort of track driving(drifting, autox and drag alike).

get the ACT6, it rocks the party.

I have an ACT 6-puck in my base model and I like it a lot. Even though I am not turbo and I do not make a whole hell of a lot of power, I love the "break-neck" launches I can get from dumping the clutch.

As for drivability, I do not even think about it anymore unless there are many, many traffic lights or super-long lines. To get the car rolling at traffic lights I just blip the throttle and let the clutch engage ever so slightly. That is usually enough to get the car rolling. You will find your own technique, but be aware you will stall the car a couple times in heavy traffic getting used to it.

I have the ACT HD Disk and EXtreme PP (i think its 430lb/ft), and lemme tell ya, holding that sucker in for long periouds of time can get a bit hard on the old left calf and hamstring!! It engages smoother than a 6-puck to be sure, but, there is NO rolling the clutch with the ball of your foot, its a full leg operation!

I've driven the sprung 6-puck design and for a comparable holding force, the pedal pressure is MUCH less. It is harsher to engage, but once you get it down, its cool.

I think if i had to do it again, i'd go with a sprung 6-puck for the easire pedal puch and deal with a bit of jitter from a stop!!

Have you had any holding issues with the organic disk? I just dont want to buy a clutch and have it slipping on me, and then have to go throught the hassle of replacing it again. I do want the X-treme PP reguardless, I just need to choose a disc.

Anyone try the pineapple sprung 6 puck disc? It is supposed to be a little nicer in engagement due to the material used on the pucks. The other benefit they say is if the disc is contaminated with oil ,washing the disc makes it usable again whereas the sintered puck ones are not.

Where have you got info on the pineapple clutches? I cant seem to get to that link on their website.

I have never had any holding issues with the ACT organic discs. Not in my GTU with a street strip clutch and PP and I see no freaking way that I'll get the TII up over 430 ft-lbs of torque on the present HD disc and XT PP, and from the feel of it at around 290 Ft-Lbs.. it'll take all of that 435ft'lbs to tear it up!!

i have a act xtreme hd clutch and PP with a aluminum lightweight flywheel. i like it . I still get a little bucking (as if i had a 4 or 6 puck). not very bad and i can control it for the most part . but as kevin was saying you loose a little low end torque. well ill tell you this .. in a NA where the torque is a little low anyway . well i cant burn out very well without dropping it at like 7 and from 750prm-2.5k i have no real power. but i do have to say one i break that plain the car moves pretty well the rpms raise very quickly. if your shooting for 400 Plus and want a driveable street car. try the ACT Xtreme HD clutch and PP. i was told it should hold to about that amount and its pretty smooth for a beefed up clutch system. although after driving my car and getting into other peoples car and pushing the clutch . i always slamm the clutch to the floor very easily due to the stiffness of my pedal. but i got used to it in a few minutes

CP racing makes a sprung 4 or 6 puck clutch, im going to get it for mine.

I have a 4 puck unsprung act clucth and a heavy duty pp. It took a little bit to get use to, but once i got it down it wasnt bad. It sucks in stop and go traffic, but each time you shift hard you can really feal the clutch engage. If i were to get a diff. one i would probaly get the 6 puck.

The ACT 6-puck and HD pp on my fc isnt that bad. It only took me a couple days to get use to it. It can be a little noisy from time to time. But it is worth how well it disengages and engages. The only thing I recommend w/ it is a ss braided clutch hose.

Shane at www.rotaryworks.com got me a really nice pressure plate.
It's high clamp pressure, but with a light pedal pressure.
(He won't say where he gets them.)
It's easy on the leg & easy on the release bearing.

With the ACT 6 puck sprung clutch & the ACT light flywheel, I get an interesting combination.

Easy starts & traffic are nice & smooth (approved by Mary).

Hard starts & shifts are rock solid (approved by me).

But, there is no in between.
As soon as you up the power, the clutch bites - clamp - and off you go.
http://208.62.166.66:82/guest/pics/9...p/clutch17.JPG

You say you have a 6-puck sprung ACT clutch? Could you tell me where you got it from? I dont mind a high pedal pressure , so Id get the ACT X-treme PP with a sprung 6-puck disc. Also, that clutch and PP look identical to the "XTD" kit that I am looking at on Ebay :
http://cgi.ebay.com/ebaymotors/ws/eB...category=33730

ive got the 6 puck unsprung. i like it. no problems.

I think you're right.
The Flywheel was definately ACT, but the pressure plate & clutch were unlabeled.

How do you like that clutch/PP combo? If that in fact is the XTD kit, you are the 1st Ive found that is actually using it. Do you think it would be good enough to hold a higher power application?

i'm tellin ya dude... spec stage2

have you checked out the exedy stage 2 Ceramettalic disks?
they make 2 versions of them, a normal disk and a thin disk. one is more streetable and another is full race.
seems to be what you are looking for. sprung, 3 puck (shaped like a rotor), and streetable.
http://www.daikin-clutch.com/products/sports.shtml
exedy is a great brand. they make all the clutch kits for ACT and are the most popular race clutch brand in japan. i