Clutch, LW flywheel and chatter....
 

I am wanting to install a light weight flywheel on my car but every review I come across claims thier set-up rattles and chatters under deceleration. This seems to be a common complaint with after market clutches and flywheels. My question is why? And what kit will allow me to have a LW flywheel without inducing chatter?

I was looking at a Exedy stage 1 kit. Or maybe stock clutch with aluminum flywheel?

I think it's hit or miss. Some clutches are loose and clatter, others don't, even between the same brands.

I'm running the ACT clutch and no clatter at all.

At idle, sometimes clutches clatter, but usually raising the idle a little helps with that.

The OEM flywheel is heavy to soak up NVH created by the engine. Using a lightweight flywheel can introduce added noise in the system.

It's usually not the clutch making noise but instead the flywheel. What you hear is lash on the transmission hub splines. Depending on how a lightweight flywheel is installed, this noise can be minimal or severe. The noise can be compounded by the clutch installed.


Even TRD states that a lightweight flywheel can cause noise and theirs is as close to "OEM" as it gets (and certainly isn't the lightest option out there).
Source: http://www.trdparts.jp/english/86_pe...owertrain.html

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Does the lash increase the ware on the gears now that there is nothing dampening them?

I seriously doubt it. Lash clatter is nothing compared to the loads they see when engaged.

An engine as it spins doesn't ever spin at one perfect uniform angular velocity throughout a revolution. Think of a single cylinder, on the downstroke after the spark plug fires it will be accelerating slightly, and on the compression upstroke it will be decelerating slightly. So you have a constant acceleration deceleration even while just sitting there at idle. It's more noticeable at slower RPMs as well. As you go down in flywheel weight those accelerations and decelerations become more prominent since there's less inertia. The same reason the revs go up and down quicker also applies in this smaller scale causing chatter. The chatter noise itself is the acceleration deceleration noise going into the transmission and the when the teeth of the gears effectively bounce off each other repeatedly from backlash. There's virtually no load however and the noise is in line with the crickets. Nothing more than an annoyance and not harmful.

The OEM flywheel isn't viscous or a DMF, it's just one heavy chunk of steel from what it looked like when I changed my clutch. It's 20-something lbs. I have a competition clutch & lwfw that's 12-13 lbs. It doesn't chatter at idle much, but on deceleration in higher gears it does. My entire car sits on poly bushings though so it's pretty loud but it never bothered me, hence poly bushings everywhere.

I think it's hit or miss if you get chatter or not. The only surefire way of not getting chatter is of course an OEM weighted flywheel, but whether or not you will specifically relies on your particular transmission and its build tolerances, fluid, etc.

Would a CF drive shaft help with chatter?

I don't think so? At least not to my knowledge. The chatter comes from in between the gears in the transmission on the input shaft and output shaft. The free play between the gears is what bounces and chatters.

No. Make it worse... I have lightweight flywheel, crank pulley, and carbon fiber driveshaft.... It's loud

I have read that the CF drive shaft acts as a dampener and can help quiet down the chatter. Maybe your car would be even louder with the stock drive shaft....

What clutch and flywheel do you have?

There's a number of reports of blown engines due to bearings on engines with lightened parts on both ends. It seems it's best to run one or the other. Without the dampening from the stock pulley or flywheel the bearings get pounded, harmonicas and such.

I'd look it up here in the forum and read up about it.

Agreed. I am trying to decide which end to lighten, hence the creation of this thread.

No, no it doesn't.

Rather than simply saying 'no', explain how it's dampened. I've never bothered breaking the OEM flywheel apart to see inside. If it's springs and not viscous then that's my mistake.

In any case it's a heavy flywheel designed with the sole purpose of reducing NVH.

Leave the stock crank pulley and lighten whatever you want on the drivetrain side. Just be prepared for any added noise that might result.

I have an ACT ProLite flywheel and HDSS clutch, stock driveshaft and 4.67 final drive. The flywheel makes noise sometimes. I don't care though. I hate heavy flywheels.

It will dampen the process of putting power to the ground but won't affect any rattle or chatter at the gearbox.