Lighten A Factory Flywheel?

[No Crust Racing]

I'm about to have the flywheel in the CA machined (mild tune 200rwkw track car).

Can it be safely lightened at all? There seems to be a lot of conjecture about this.

Anything is a gain and it won't cost much more than having it machined. I will ask the place tomorrow, but thought some opinions couldn't hurt.

Clutch is a basic Xtreme HD Organic.

[GTSBoy]

Yeah, you can machine a lot of weight off of cast flywheels. But really, these days with new light chrome-moly ones being so cheap, why would you put up with the risk of it exploding?

[34GeeTeeTee]

Why do you need a light flywheel?

[No Crust Racing]

Just seeing what the options are. Like any job I do, when it's all apart you're going to have a look around and think how can I improve this or what other things need replacing while I'm in there.

So it was just a case of "if" not "need".

General consensus seems to be it can be done, to a degree, but the risks go up, So I'll just get this one machined and put it back in. I can't justify $300 or so on a new lightened flywheel.

[rev210]

machining the cast iron flywheel is fine to resurface. But to machine till you serious Lighten..... dumb.

The outer skin of cast iron is where it's strength is. removing it seriously reduces the strength.

Bottom line is that there are plenty of true stories about lightened cast iron flywheels letting go. It's when they are put in high load / heat cycles. A clutch and flywheel breaking up a speed is a scary situation. Google this . You should have no trouble seeing the reccomendations against it.

Get a chrome molly one with the new clutch. They are like $400 or less

[No Crust Racing]

It's already back in the car Rev, just machined it and put it back with new ARP bolts.

[34GeeTeeTee]

machining the cast iron flywheel is fine to resurface. But to machine till you serious Lighten..... dumb.

The outer skin of cast iron is where it's strength is. removing it seriously reduces the strength.

Bottom line is that there are plenty of true stories about lightened cast iron flywheels letting go. It's when they are put in high load / heat cycles. A clutch and flywheel breaking up a speed is a scary situation. Google this . You should have no trouble seeing the reccomendations against it.

Get a chrome molly one with the new clutch. They are like $400 or less

Nothing wrong with the Heavier style flywheels, go have a look through my build thread and see my custom version... Heavier than stock and awesome!

[rev210]

cast iron flywheel --lightened. Theres a few of these on youtube. You also get this with dodgy clutches too, if they let go.

Heavier flywheels that stock can make the driving /shifting easier. It also depends where the mass of the flywheel is distributed.

[rev210]

Removing rotational mass has significant performance benifits.

The performance benifits of a decreasing the mass are well documented.

Heavier flywheels offer drivabillity . Light weight = performance gains. Is the same for wheel weights.

[rev210]

On a gtr or gtst the lightweight off the shelf chrome molly flywheels are nice to drive , from my own experience. And the car will noticably and measurably accellerate faster.

[34GeeTeeTee]

Removing rotational mass has significant performance benifits.

The performance benifits of a decreasing the mass are well documented.

Heavier flywheels offer drivabillity . Light weight = performance gains. Is the same for wheel weights.

What performance gains? Can you point me to any info showing this?

Mine has plenty of performance and changing to the new setup changed the car, its so much better to drive now!

[rev210]

What performance gains? Can you point me to any info showing this?

Mine has plenty of performance and changing to the new setup changed the car, its so much better to drive now!

Sure. I'll have look for you later. You can google the info pretty easily. Flywheels , like wheel weight are rotational mass. You can find out the physics behind that as well if you would like. It's fairly common knowledge.

The main reason passenger cars have heavier flywheels is to assist in intertia where it helps improve daily driving. Just off idle and cruising smoothness. Probably why the car feels nicer to drive.

[discopotato03]

The advantage is less mass to accelerate which tends to be more noticeable in lower gears .

IMO the greatest advantage of light flywheels is that the engine revs drop faster on the up changes particularly if you use high revs . Anyone who's drag raced with a manual syncro box knows how important this is .

The downside is such a mod makes it easier to stall when taking off because there is not the initial inertia to send down the driveline . Also especially noticeable in a cammy cranky engine .

A .