upgradesRX

i just recently instead a exedy hyper single clutch on my 8 and im getting some pretty annoying clutch chatter or trans noise, just wondering if anyone else has installed a pucked clutch on there 8.

ACTman

A puck disc is basically a race clutch. Are you planing on dedicating the car to racing? If not, you have way more clutch than you need.

Sigma

The chatter will lessen with time, but it will never go away, and it will be particularly bad when it's cold. Slipping it to some extent to warm it up might help on those first few morning shifts where the chatter is greater, but if it's Kevlar slipping and chattering will cause it to glaze over.

If it's a Kevlar clutch is helps to give it a good hard shift every now and again. It keeps the kevlar from glazing over from the chattering which will help with the chatter and smooth engagement quite a bit.

upgradesRX

ive got about 700 miles on the clutch now and the chatter is still there but ive gotten use to it. ive had plenty of pucked clutches before some even 3 puck so its not a big thing to deal with. the hyper single is great though, nice engagement and the flywheel is awesome.

Im_DANomite

iTrader: (1)

puck clutches kill flywheels...

KYLiquid

i can understand the flywheel, and also the clutch change at the same time, i like a heavy feel, but why so hard core? what are your future plans?

upgradesRX

the rx8 is pretty much gonna be one of my shop cars, and i plan on putting some high #s through it even if it blows. and i get a great deal on exedy and like there product, i put a twin plate hyper in a sti and loved it, that pretty much made my final decision.

ACTman

You guys need to learn a little about clutches. Let me help.
1) Puck clutches don't kill flywheels. At least not if the right materials are used on both the flywheel and the disc. Too soft of a flywheel material (some aftermarket ones especially) will get torn up with an aggressive disc like ceramic. Not only does the flywheel get torn up but the disc too. There are some friction materials out there also that are more abrasion than friction. There is a big difference between the two.
2) Kevlar has a low coefficient of friction so it will hold less power than a stock disc in most cases.
3) Chatter can be from having too much friction or it can be from having no cushioning between the linings. Even with a mild material like Kevlar, you will get chatter if there is no marcel (wavy metal between the linings).
4) True glazing of the clutch disc is desirable and what happens when the clutch breaks in. Once a clutch is glazed (or lapped in) the wear rate is lessened tremenously. The friction goes down a bit when glazed but it is consistent. If you are relying on the disc not being glazed in order to hold the power, then what you really need is more clamp load or a more aggressive friction material so you can hold the power when the clutch does glaze.

Sigma

I don't doubt that you know what you're talking about ACTman, but your information, particularly #2 and #4 (#1 and #3 I agree with), disagree wholly with what I both know out of my experiences with clutches as well as what SPEC (I am a SPEC reseller) themselves have told me.

Glazing is the Kevlar clutches worst enemy. You can build up glaze on the clutch very quickly just getting stuck in traffic a while, and the clutch will start to slip and barely hold any power, and a good hard shift wears them clean again. Often times kevlar clutches get so glazed over that they must be removed and media-blasted.

I currently am using a segmented kevlar disc in my '03 Mazda6s. It chatters like a **** and most definitely and very obviously glazes over in traffic. I just give it a good hard 1-2 shift, and it feels as good as the day it broke in after that.

army_rx8

hmm i put in a street/strip clutch (made my clutchnet got from racingbeat) and i hear a clatter but only when i am in reverse or 1st (and only when engaging the gear)....very annouying (it is not pucked...looks like stock clutch but with 6 springs instead of 4, and slighty tougher material)...any ideas why it's making that noise? i'm droping my car off at the guys who installed it..i'm hoping it's just a clutch adjustment..or pressure plate adjustment. haha kida' anouying it isn't a racing clutch why is it sound liek on. lol

Sigma

Some amount of chatter, particularly in R and 1st, is just a byproduct of a stronger material. There's really no way around it. It usually lessens with time as the clutch become more broken in, and sometimes severe chatter is a result of a bad installation, but some chatter will always be there. A non-segmented street clutch shouldn't chatter that much.

army_rx8

^seriously it non-segmated and has marcel's like the stock one...hha but it still sounds like a damn double clutch . lol now if only i had one of those granted it would be super over kill on a daily-driver. ah well i'll find out for sure what is going on thursday.

ACTman

Don't know for sure, but it could be from torsional vibrations not getting dampened out as well from the aftermarket disc versus the stock disc.

ACTman

How can you disagree when you are proving my point? I totally agree with what you are saying. IMO, It is too slippery when it is broken in properly for any other disc (glazed as you put it). This very nature of Kevlar is why we don't use it on our clutches. Even when it's not glazed, the coefficient of friction is low compared to a good organic material in the same condition. Don't get me wrong. I am not trying to pick on the material. There are some desirable benefits to Kevlar as well, such as good wear rate and low abrasion. We are only scratching the surface on this type of discussion though and I don't want to get too OT.

Sigma

I disagree that Glazing is "desireable" -- at least on a Kevlar Disc.

And I also disagree that Kevlar holds less power than a stock disc. If that was the case, many manufacturers wouldn't make their upgraded (usually "Stage 2" or thereabouts) clutches with Kevlar discs. The Stage 2 in my Mazda6, as with almost all of SPECs' Kevlar clutches, is rated at anywhere from 50% to 100% more holding power than the respective stock clutch. Mine is rated for 400 lb/ft. I wish I could tell you how it works at that power, but I can't. Kevlar works just fine on turbo 3.0L SVT Contours (comparable to the Mazda6) doing about 400 lb/ft to the wheels though, although at that kind of power a carbon disc of some sort is preferred of course.

I will grant that Kevlar holds less power than the same design of a carbon compound, and even less than some organic discs out there. But it absolutely holds power more than most organic-compound stock discs -- unless you're talking about a car with some absurdly strong stock organic disc. I'm finding it hard to believe that "most" stock discs are rated for 350-400 lb/ft.

upgradesRX

you guys are more into this then me, i resell many different manufacturers clutches and i dont really question what they are made out of as long as they work, ive done enough by trial and error to pretty much decide which is better for which app, i went with the exedy hyper single because it is spun balanced to 15,000 rpm to reduce vibrations that may be caused by a pucked clutch and besides that pucked clutchs dont bother me ive drove plenty of cars with 5000lbs pressure plates and i can deal with it, the only down fall i see with this clutch is a lil chatter, but thats covered up by the rotarys exhaust.

ACTman

So you are saying that Kevlar will definitely will hold more power than stock organic and less than maybe other organics, but it won't hold squat if it is glazed, and glazing is bad, correct? And as long as the disc isn't glazed it will hold 50-100% more power? And you have to drive it a certain way to de-glaze it every once in a while? Uhh...OK.

What I am saying is that glazing is normal and desirable for, let's just say, normal discs. Just like what you are saying about Kevlar is true for organic materials as well. If you have ever put a new stock clutch in a car and beat on it, you know that it may chirp the tires in third for the first week or so and then it won't after that. Before you break them in properly (glaze them) the material has a much higher friction and therefore holds more power. The problem is that organic materials will wear at a faster rate until it is broken in.

You are giving the friction material more credit than it's worth in regards to increases in the clutch's torque capacity. Discs may influence torque capacity as much as 40% and that is about it. The rest of the job is done by the clamp load of the pressure plate.

Rather than debate here, I would gladly discuss this futher via email if interested.

ACTman

They are burst tested to 15000 rpm, not spin balanced to that rpm. This is a requirement for SFI certification.

upgradesRX

you may be right but from what ive been told from exedy they spin balance them as a installed unit, the clutch and the flywheel balanced together and marked, so when you install them you line up the marks, i dont know any other clutch company that offers a clutch and flywheel that comes as one unit.

ACTman

That is probably true on the Hyper versions from Exedy since they only sell them as a set. The only problem is that on the RX8, the rear counterweight from the automatic is a different balance than the manual shift flywheel you are replacing. To get it right you either have to custom balance the rear counterweight to match the manual shift flywheel or change both and back counterweights to the automatic ones.

upgradesRX

so your saying that the rx8's stock flywheel is off a automatic transmission car even though its a 6spd?

Jaguar_MBA

ACT MAN. I have the Racing Beat aluminum flywheel and it has the replaceable contact surface..not sure if it is Kevlar or some organic compund. This Flywheel is mating to the stock clutch......which I imagine has an ogranic compound for the mating surface. Is it ok to have an Organic material to Organic Material mating when the clutch engages to the flywheel? What is the best combination to have?

ACTman

OK, let me see if I can explain it adequately.
All rotary engines are balanced externally (meaning outside of eccentric shaft balancing). There is counterbalancing on the front and the back of the engine that is 180 degrees apart (they counteract eachother)
Engines from stock manual shift cars: front counterweight attaches to shaft inside the front cover, rear balancing is done as part of the flywheel (more weight is cast on one side).
Engines from automatic shift cars: front counterweight attaches to shaft inside the front cover, rear balancing is done through a rear counterweight that the thin flexplate bolts to.
Aftermarket flywheels: In general, they are neutral balanced and attach to a Mazda automatic counterweight just like the stock automatic flexplate does rather than bolting directly to the shaft.

Here is the trick: The front counterweights on the automatic and manual RX8 engines are different. As a result, so is the amount of counterbalance built into the manual flywheel and automatic rear counterweight. A custom balanced automatic counterweight is required to bolt the aftermarket flywheel to, or you have to change to the automatic front counterweight in order to get the balance right.

ACTman

I am sure they are referring to a replaceable insert, like most aluminum flywheels. It is made of steel, don't know what kind on the Racing Beat. Call them.

upgradesRX

ok, i might be a retard but i dont understand y you are talking about automatics. i have a aftermarket counterweight on the flywheel, is that what you are refering too?