Centerforce vs. ACT, how hard on the flywheel?

[Guest bastaad525]

jmortensen - Heh... the ACT setup is exactly that!!! (thighmaster)

 

 

I don't really do a lot of slipping like that when I'm leaving lights or whatever. I'm still pretty bad at launching it well so I really dont even try... I usually just dissapoint myself . My thrills come from 50-80mph highway passing, and getting the tires spinning coming on boost in a turn. Only the few times that I've raced or if I really want to get the tires to spin leaving a light. Well if I can get 50k miles on this clutch I'll be a very happy camper indeed... as I said I REALLY felt cheated when I looked at my records and found I had only put about 25k miles on that ACT and had seen how badly worn everything was from that. I'm REALLY loving the stock style clutch, and though I haven't done your little test, the clutch has held fine the few times I've pushed it. Hell if I can get 30k I'll be happy

 

So now I have another question. If a stock clutch disk will hold a lot of power if you use a strong pressure plate, what is the point of using one of the metallic clutches at all?? I mean dude you have REALLY opened my eyes here... all that time driving with the ACT, living with chatter and a sore left leg, and for what?? What power point do you really need to be at before something like an ACT is a necessity? When is it worth the tradeoff of destroying thrust bearings as well as the aforementioned chatter and sore leg?

 

Doesn't seem worth it to me... I'd bet a lot of guys running them probably don't need them.

[JMortensen]

The only people I personally know that run the button or puck clutches are the people who were told that it was cool (not meant to be an insult to you or anyone else, but that's a true statement). I'm SURE that there are those on this list that would fry my setup in a day. There are people here that NEED the button disks, but I'm also sure that they are just a handful of people. John Coffey always says that people overbuild their brakes. I disagree with him on that, but I do think people tend to overbuild their clutch.

 

I had a Nissan master tech and 510 and Z guy as a roommate for a couple of years and he helped me put my car together the first time. I kept saying I wanted a badass clutch, and he convinced me to drive it stock until I had a problem, then upgrade as necessary. As far as upgrading, he always said to get a heavy pp and a stock disk (Paraut disk was what he always recommended). He was also the one that rebuilt my other friend's 200SXT that had the CF DF that ruined the thrust bearings, and he showed me the damaged caused by it. That turbo engine did not make enough power to slip the stock clutch after being rebuilt. All that damage for no gain whatsoever, and a hellacious chatter to boot. Not all of the advice that my ex-roommate gave me was that good, but I think that particular piece of advice is very good, and I think you're right that MOST people that have them don't need them.

 

Oh, and the weakness of a stock clutch disk is the springs. If you've got big power and you're shifting hard but the clutch isn't slipping, the springs will give out first. If you have the disc out and the springs rattle, replace the disk. I can only imagine that the puck disks with springs must go bad in about a week, but I've never run one so I can't say for sure.

 

Jon

[Guest bastaad525]

Really.... yeah the ACT I had had no springs on the disk... which everyone said was the wrong way to go, BTW. The Daikin metallic disk I was going to buy had springs. What the heck do those springs do anyways?

 

You're right about the ACT... well partially I bought it for bragging rights (it's got a RACING clutch!) but also because I was told by a couple guys that no way the stock clutch would hold the power I was making... this was with my N/A motor which ended up peaking at 170rwhp before I swapped to the turbo... which at 200rwhp seems to be doing just fine with the stock clutch... hmmmm

 

Well it's cool I've learned my lesson now... sux that I had to suffer the ACT for years though but better late than never. Whenever this clutch finally goes out I'll go back to an ACT pressure plate but stay with the stock disk, I think. Should I ever get thru all these problems I've been having, my max target hp was 250hp to the wheels... ACT PP and stock disk should be good for that yes?

[JMortensen]

Should I ever get thru all these problems I've been having, my max target hp was 250hp to the wheels... ACT PP and stock disk should be good for that yes?

I'd say definitely, but I know better...

 

EDIT--the springs are supposed to reduce the chatter and provide a smoother engagement.

[Guest dvlax28]

Talked to a clutch guy, and he said I have a centerforce clutch, they're usually gold colored, and the weights in the middle supposedly only kick in at about 5500 rpm, and I dont know about you guys but I'm scared of a my car that high. Just a little info i grabbed from the Clutch Doctor in AZ.

[JMortensen]

dvlax, if you have a NA motor and you aren't revving past 5500, you're missing the best part. I understand that there are some issues with the turbos and air/fuel ratios at that rpm with the stock computer, but having a NA Z and not using the whole rpm range is missing the whole point! You gotta use what you've got, and these cars love to rev.

 

Jon

[clint78z]

Things to consider when buying a clutch, you are right buying the bad ass clutch may not be for you. Now there are several facotrs controlling how a clutch functions.

 

The diameter of the clutch relates to the friction surface area. The more sirface area the easier it is for the clutch to do it's job. It pays to get the 240mm clutch.

 

The pressure plate has springs in it that exert a constant presssure against the clutch. It can be calculated back to clamping force of the clutch given a known surface area. Increasing this will make the clutch less likely to slip. It is harder on the thrust bearings nad gives stiff pedal pressure.

 

The clutch disc can be sprung or unsprung, the springs make the engagment less quick and reduce chatter. The material on the clutch disc can change the coefficent of friction. If you go with a higher coeffecient of friction once it slips it will eat the flywheel faster. If you go with puck disc it decrease surface area w=p/a, but increases effective clamping load (typically a higher coeff of friction of material is used. Sucks for the street

 

What I would recommend to most people is use a 240mm clutch, increase pressure plate by 20-30% and go with a carbon kevlar disc full faced with a sprung hub. The carbon kevlar disc performs grips better than stock at high temps when it slips a little and won't eat the flywheel.

 

This should be good for most ppl pushing 300hp, of course if you are mean on the clutch or run slicks and drag race lots I would step it up another notch.

 

If you go too nasty you will have chaterring, broken drivetrain parts, on/off behaviour, toasted flywheel....

Choose wisely

[Guest bastaad525]

dvlax' date=' if you have a NA motor and you aren't revving past 5500, you're missing the best part. I understand that there are some issues with the turbos and air/fuel ratios at that rpm with the stock computer, but having a NA Z and not using the whole rpm range is missing the whole point! You gotta use what you've got, and these cars love to rev.

 

Jon[/quote']

 

 

My 2.9L N/A motor with a 480 lift 270 duration cam and mildly tweaked SU's, N42 head and 3-2-1 headers, fell off sharply in torque and HP after 5500rpm...

[JMortensen]

Let's not start the whole triples vs SU thing again, OK???

[Guest bastaad525]

heheh.... no please don't! I do realize that with triples my power band would easily have extended past 5500rpm. But I will say this, that motor was originally in my '80 ZX, with the mostly stock EFI, and a 60mm throttle body... on the dyno it still fell off at 5500rpm.... I think this was more a limitation of my head, which I had mostly left alone, than of the induction system.