Lightened flywheel shutter
 

Whenever I burn the clutch in first gear on a hill the car has a mean shutter. Its only when I first start and no other times. Is this my aftermarket alluminum flywheel? I have a ACT six puck w/ extreme pressure plate and an alluminum flywheel from Mazdatrix. They are all brand new parts.

i believe thats clutch chatter, and with a 6puck and if i remember correctly that cant be avoided.... then again it's not exactly bad from what i'm told....

Yeah, I think its more the 6-puck than the flywheel thats the problem.

Does anyone else have a six puck? Does it do the same thing or do some burn smoothly. Cause its pretty bad where it shakes the whole car! Enough for my foot to shake so much I can't keep the gas pedal steady enough and it sometimes dies or revs up. Its pretty embarassing on hills. Do most people here just run street clutches?

does the six puck have a sprung center?? If not, thats what is causing the shutter. Unsprung centers work better as high rpm --drop the hammer disc's. I've heard of others running them too, and the same stuff happening.

Starting smoothly in an RX-7 with an unsprung 6-puck is something of an art. Even after three years I still chatter it once in a great while. Just how it is, heh.

yep dude you'll have to live with it....

but to ease your pain, it's normal....

Thanks for the help guys. I was just in the process of rebuilding and almost was gonna change to my stock flywheel setup to see if it went away. Now I know better, thanks!

yeah, it takes a little while to get used to having a 6 puck and LW flywheel. Its pretty funny when you let somebody else drive it and they stall it b4 they make it out of the driveway.

Theft prevention. Even if they do start it, they won't be able to get it anywhere.

I want a lightweight flywheel, but my NA doesn't make enough power that I need any fancy sort of clutch.

-=Russ=-

Bah, they'll just throw it on a flat-bed. ;) Do the sprung center 6-pucks have significantly less chatter? I'm kinda doing some shopping trying to see if converting my GXL to turbo will be worth the extra bucks and that's one of the things on the list. ;)

HAHAHAHAHAHAHA!!!!!!!!!!!!!!

that is so true!!!!!!!!

:bigthumb:

shudder sucks....it took me a while to figure out how to get it smooth...

The springs in the clutch center absorb some of the shock of taking up the drive. Without the springs, the shock will be transferred to the rest of the drivetrain, so you get shudder. The good part is that more of your torque is making it to the rear wheels.

The Mazdatrix or Racing Beat torque brace for the engine works well at eliminating the shudder.

Edit: my experience with the torque brace is that it eliminates shudder with the heavy duty clutches, which have less center springing than stock. I don't know that it will eliminate shudder on a springless 6-puck, and I shouldn't have said that. I'm sure it would help, but I can't say that it will eliminate it.

Cool, good to know, thanks. ;)

The torque brace is definatly a good idea but I'd make sure to replace your motor mounts with new solid or poly mounts and make sure the subframe is in good shape.

I've seen many accounts where adding a torque brace will wear down the motor mounts much faster and in high-torque turbo applications can shear them out-right if they're still the stock style.

how far is the new clutch broken in? Mine shuttered a ton when I first put it in, now after about 1,000 miles it is completly broken in and I get a shutter every once in a while taking off in 1st.

Whoever the idiot who recommended that combination should be shot.

The 6-puck copper disk is NOT meant to be slipped!
Stop trying to slip it!
It's going to eat your lightened flywheel in a few months.

If it's chattering, you're trying to slip the clutch.
You just need to dump it when you engage it.
That's how you're supposed to drive a copper puck clutch.
Slipping a copper puck clutch will cause the copper pucks to eat into the flywheel!


-Ted

i went to a mechanic, and HE stalled in front of his shop driveway.....

Springs have nothing to do with chatter (shudder). Actually a spring centered disc tends to make chatter worse. What causes the chatter is the higher friction. Chatter only occurs because when combined with flexible mounts, the engine tends to wind up in it's mounts as the higher friction clutch material occilates from slipping to grabbing. With solid mounts there is no chatter even with the most aggressive discs because there is no windup affect. On the other hand springs in the disc tends to increase the windup and therefore increase chatter.

Now for the original question about the shudder. There is no doubt that the disc is causing most of the chatter but the flywheel also in contributing to it as well. This is because the replacable surface of the flywheel is not flat. They are never flat. The high spots between the little bolts contact the segments (pucks) of the disc and smooth engagement is going to be very difficult to achieve. A solid flywheel will engage smoother but still not what I would consider streetable. I would consider more of a street setup unless you are making some crazy torque numbers. What you have is what normally goes into 8 second drag cars like Ray Lochhead's!

???? Clutches are designed to slip, especially the puck discs. Actually it is better to break in a puck disc by slipping it under pretty high load, especially on our older friction material. If you are too gentle the pucks don't lap in and just remain rough and cause more wear to the flywheel. But if the flywheel is getting eaten by the pucks, it's a lousy flywheel. Some of the flywheels out there use really soft surfaces like just plain jane 1018 steel or something that doesn't put up to agressive materials.

[QUOTE=ACTman]Springs have nothing to do with chatter (shudder). Actually a spring centered disc tends to make chatter worse. What causes the chatter is the higher friction. Chatter only occurs because when combined with flexible mounts, the engine tends to wind up in it's mounts as the higher friction clutch material occilates from slipping to grabbing. With solid mounts there is no chatter even with the most aggressive discs because there is no windup affect. On the other hand springs in the disc tends to increase the windup and therefore increase chatter.QUOTE]

Then, why have springs? Don't springs store energy? Energy that would otherwise be transferred to the drivetrain, increasing windup? Wouldn't that energy be released as torque being applied to the disc material is decreasing, thereby smoothing the on/off effects of the clutch grabbing/releasing that you described? Is there some sort of hysterisis (sp) effect? Why is it that heavy duty clutches with stiffer springs produce more judder/chatter/shudder that more softly sprung discs.

Everything else you say makes sense, and you apparently have expertise. So (with all due respect), maybe you can explain the intended role of the springs, and why they increase windup.

Who the fuck are you???
Sorry to be so abrasive, but that's some of the most bullshit I've seen in a LONG time.

Do you work for ACT???

Copper puck clutches are NOT meant to be slipped.

Copper puck clutches do NOT need a break-in.

Where are you getting this bullshit from???


-Ted

The main reason for springs in a factory disc is to absorb torsional vibrations (rotational pulses) that are generated by the engine. These torsional vibrations cause the gears to rattle primarily when not under load which is noisy. Springs in the disc (or flywheel in the case of a dual mass flywheel) dampen these pulses and reduce or eliminate the noise associated with it.
You have to understand what chatter is to understand why springs can (not always) make it worse. Chatter is the engine moving back and forth from having rubber mounts, as the clutch is trying to engage. The higher friction of puck clutches makes the engagement "rough" to put it simply and with flexible mounts, you get chatter by the engine bouncing in the mounts. If you have solid mounts, the "wind up" is gone and therefore chatter is gone. By putting springs in the clutch you basically are allowing wind up on the other end and therefore increase the chatter.
Feel free to email me for more information at dstarksen@advancedclutch.com.

^
Thanks for your answer. I understand about limiting windup in the drivetrain, and used an engine torque brace to prevent that in my own car. Nevertheless, I remain unconvinced with your explanation of the clutch springs' effect.

I see them absorbing and storing energy under high torque loads, and releasing that energy when the torque load decreases, which should smooth out the windup effects. Also, I remember (30 years ago) seeing the old style chrome bumpers vibrating up and down on cars with clutch chatter. That tells me that the chatter is also on the parts of the drive train aft of the clutch, in addition to the engine. Springs would certainly smooth that effect.

You crack me up, dude. Check out http://auto.howstuffworks.com/clutch1.htm. ALL clutches are meant to be slipped! That is the main purpose for a clutch in the first place: to SLIP as you are enagaging to get the care moving while the engine is already running or to smooth the transition to the next gear. Why else would there be friction material in the first place. Otherwise we would just just bolt the crankshaft to the transmission shaft and use some sort of dog to instantly engage the gear, similar to a sprint car (they get push started).

Besides the benefits copper or other sintered materials of having high friction to hold more power, they also have high heat capacity. Where do you think the heat comes from... slipping! I used to say that puck clutches don't need a break in until we did some clutch testing on the dyno. We were measuring torque while the clutch is being slipped. We found that if the material is allowed to bed in a bit then more material made contact and it held more power.

To answer your other question, yeah, I work for ACT. You asked where am I getting this "BS" from? From 28 years in performance clutches, test results, race car experience, studying engineering data, but I still have a lot to learn. It is sometimes difficult to explain things in a few paragraphs on a public forum but that doesn't mean it is BS.

Drop me an email if you are truely interested and I will take more time to elaborate on it further.

^
Thanks.

Jim,

The sprung center hub doesn't do anything for engagement as the springs are much to stiff to be compressed. The sprung hub is to reduce shock loading in the drivetrain. Unless you engage the clutch at high RPM and apply a lot of torque the springs are just along for the ride. Sidestepping the clutch for a drag launch will make those springs work.

So you're saying we should slip the copper puck disc just as much as an organic one?
I was told this was a big no-no!

The copper puck material gets "more aggressive" as heat builds, right?
If this is true, doesn't excessive slipping cause the pucks to eat into flywheel / PP?
Or is that all wrong also?


This is with a Racing Beat lightened flywheel on a 1987 FC turbo.
I can't comment on the composition on what Racing Beat uses in their flywheels, but it can't be that bad?

Any comments on those chrome-moly flywheels which seem to be all the rage?


-Ted

When did this change of policy went into effect?

Is this Dirk?
Got tired of playing with Hondas, Supras, and DSM's? :)


-Ted

You should only slip the disc the amount that makes sense whether copper or organic. What I am saying is that the copper material can take the heat from slipping better. We found that our current material is fairly consistent as it gets hot. It increases friction slightly, while you can expect a typical organic material will loose friction as it gets hot. Of course different friction materials perform differently.

I don't know about RB flywheels and what they use either. On other applications I have seen puck discs worn down to nothing on the aluminum flywheel side because of too soft of material for the insert, while the pressure plate side of the disc is hardly broken in. The same flywheel however will probably last perfectly fine on a street disc, so you I guess you could blame the friction material if you wanted. Actually it doesn't matter though, soft steel and copper/ceramic don't go together. I could comment on chrome-moly flywheels, but since that is what we make, it would be biased. I think I made comment on this on another thread yesterday. Found it: https://www.rx7club.com/forum/showthread.php?t=448630

BUT WOULDNT that effect the flywheel somehow! I myself have a 6 puck that i will installed and im more conserned about the 11 pound flywheel more than that clutch!


EDIT: is it that hard to launch soft on a 6 puck where you have to get used to it!

Yes, slipping a clutch does affect the flywheel. I assume you are talking about wear on the flywheel, correct? There are other affects, depending on how much you slip the clutch. If the flywheel is made properly the wear is not bad at all, but some cheap flywheels are real soft and puck materials have a tendancy to tear them up which is not normal wear.

Keep in mind that our puck discs hold about 30% more than a street disc so that extra friction does tend to equate to more wear. On a flywheel used with a street disc, you may get .001" wear after a clutch is worn out, while you may get .004" flywheel wear on the puck. Don't flame me if other experiences are different. These are not actual test result numbers since there are too many variables, just an idea of what you should expect to encounter. The point is that normal wear is usually minimal. Also keep in mind that flywheels don't usually have to be resurfaced because of wear, but because of warpage or heat spots. Any flywheel with cracks should be replaced.

ok but what about the other question i asked on how hard is it to move the car on a 6 puck without stalling. someone said you have to have a car length distance from you and the person in front!

It can be tough to modulate unless you are driving agressively. It engages smoother when you put more load to the clutch (like a drag launch for instance). I am not sure on the 7 but some cars are worse than others regarding chatter (on/off clutch feel). That is why we don't normally recommend them for the street.

Gee Dirk, when did you make CEO?
Got too much time on your hands so you go perusing forums like this now?
Still ignoring my question? :(


-Ted

Ted,
Speak to the hand!...
Just kidding.

I thought I answered most of them. I ignored some of the less intellegent questions like "who the *** are you?", "Where are you getting this bull**** from???" and "Got tired of playing with Hondas, Supras, and DSM's?". I figured it didn't have much to do with the subject of the thread.

To answer your latest question, I like going onto forums because I like people and if I can help them or have a healthy discussion, that's great.

BTW: I am not the CEO. I sucked at it, so I fired myself and hired someone who could do the job better. Long story.

Would love to ask a ton of questions, but it'll just dirty up this thread even more... :)


The website needs to be changed then. :)
It still lists you as President and CEO.
Weren't you just a tech when you first started??? :eek:


-Ted

I am pretty faithful about email if you would like more info. Check your eyes! In the company section, the website says that I am the "President and Chief TECHNICAL Officer". Yes, 11 years ago when I started the company, I started as a tech, ...and janitor, and bookeeper, and engineer, and investor, and... well you get the idea. Long hours, late nights, on top of my other full time job.

this.. is a GREAT read.
archieve it for puck knowledge???