How exactly does an aftermarket clutch like an Exedy or Cluchmasters improve performance? Does it reduces drivetrain friction? What about flywheels?? Lighter vs heavy?? It's good to change both at the same time right???

I'm confused....

 

If I understand correctly, an upgraded clutch has between 20% and 50% more holding power. A lightened flywheel will increase rev speed slightly meaning your engine will rev quicker, but yes if mated to an upgraded clutch I've heard rev acceleration is much improved.

Anybody else? I don't know that much when it comes to this, did I miss anything?

 

well the clutch probably wont make any feelable difference while driving unless you have an overwhelming amount of power and your other one was slipping.... but on hard launches, hard shifting, it will grab a lot faster....... the flywheel will make the rpms jump up a lot quick as it will require less power to get it rolling, but the rpms will also drop quicker, so if you are a good shifter you can make up for it.....

 

Actually, an aftermarket clutch can have anywhere from 0% additional holding power [equal to stock] clear up to 150% more holding power than stock [1 1/2 times the clamping force of the stock pressure plate]. By changing what friction material the clutch disk uses along with the clamping force, you can get a clutch that holds more power under more abusive conditions [hard shifting and launches, and/or just a lot more engine power], yet can still be gentle enough for daily driving in the city [My ClutchMaster's Stage 3 kit comes to mind for this].

Lighter flywheels reduce the moment of inertia of the engine. This means that less force is required to spin it up to the same RPM of a heavier flywheel, but by the same token also means it has less rotational inertia. Lighter flywheels show thier gains after the car has started moving, but doing so requires a higher starting RPM due to the lack of inertia a heavier flywheel has [resists slowing down as much]. Also since a ligher flywheel has less inertia, it means that it will lose RPM between shifts faster than an engine with a stock flywheel. The skinny of it is that the engine will both gain and lose RPM faster with lighter flywheel.

And yes, it is generally a good idea to change both, especially if you plan on changing the flywheel. While you could change the clutch without changing the flywheel, I would suggest strongly against re-using a clutch on a new flywheel.

 

What about the throw out bearing??? Is that part of the clutch/flywheel system?? What are the symptoms of a bad throw out bearing???

 

Yes, it's part of the clutch system, and should be replaced any time you replace the clutch. Grinding when you push in the pedal, and/or squealing. Most throw out bearings last at least as long as the clutch, but asking them to go longer [ie, reusing the throw out bearing when replacing the friction disk and pressure plate] is not a good idea.

 

There are a variety of reasons to select an aftermarket clutch. One of them is holding power, but that's really just the tip of the iceberg. What kind of clutch you want depends on what you want to do with it. For some applications you want a clutch that grabs like an on/off switch; just dump the clutch and hang on. Other applications benefit from having smoother clutch engagement. Some clutches are designed to last a long time, while others are built to be adjusted a lot. It all depends on what kind of driving you do.

Flywheel weight also depends on the application. A lighter flywheel will allow the engine to rev faster, while a heavier flywheel helps keep the engine from stalling. Most of the time you want to strike a balance between the two.

The throwout bearing rides on the transmission input shaft, but is used to press against the clutch, which is bolted to the engine. That pressure is what engages and disengages the clutch. The bearing keeps the spinning stuff and the non-spinning stuff from messing with each-other. You can tell when your throwout bearing is starting to go bad when you feel a pronounced pulsing from the clutch pedal. Let it go, and it can mess up your clutch and/or transmission input shaft, requiring replacement. There's also a pilot bearing (or bushing) where the input shaft meets the flywheel.

 

Good info here, i'm gonna post this link to help out a bit.

http://www.ks-motorsports.com/index....e=dsp_techInfo

 

Does the throw out bearing come with every new aftermarket clutch? My clutch squeaks when I engage it. It's been doing this for a while. Is this most likely my problem.

 

Usually, yes.

If/when you go in to replace the clutch and everything, be sure to lubricate all the moving parts on the transmission that are apart of the clutch disengagement.