Dealer is replacing my trans and I wanted to know which is better the JWT(14lbs) or RPS(18lbs) flywheel? would you guys leave the clutch and pressure plate assy...car has 6k miles...looking for your guys expertise

 

I'm not an expert on flywheels, but I've heard a lot of praise about the JWT flywheel and clutch combo. I don't know if you can use the stock clutch though, but I think you might be able to (don't quote me on this). If you're looking from a purely scientific standpoint and assuming both diameters of the flywheel are the same, the JWT is the better choice. There's less rotational mass so the engine will be able to rev faster (JWT also makes a lot of good products so we know a lot of R&D has gone into it). Good luck!

 

I have the JWT flywheel with the stock clutch. Works great! My opinion is if you're not going to do forced induction save your money and keep the stock clutch... especially people with very few miles on their stock clutch. The only serious benefit an aftermarket clutch will give you is additional clamping force, but if you're not going to need it... why spend the money?

However, I've been told the Nismo clutch is a pound or two lighter than the stock clutch, while the JWT unit is about the same weight as the stock clutch. So if you need the additional clamping force of an aftermarket clutch, the Nismo clutch might drop another couple of pounds over the JWT clutch. (That's just what I'm told.)

 

lighter = better
less rotational mass = acceleration horse power
when the rotational mass is moved to the inside of the flywheel = the moment of inertia is decreased

 

I think Jason is trying to sell you on the Tilton kit. One of the big things about the Tilton is not just that it's much lighter, but it's also smaller in diameter than the stock sized units. I believe the Tilton is 7.25" compared to the stock 10" or 12" or so. This means that not only is it lighter, but all that weight is moved further in which also helps reduce rotational inertia.

For example, consider this. Assume you have two flywheels of the same diameter and they both weigh the same. However, one is designed so that most of the weight is distributed near the center, while the other is designed so that much of the weight is distributed near the outer edge. The flywheel with more weight near the center will *feel* lighter when you're revving the engine, even though it weighs the same as the other flywheel. This same idea applies to wheels, also. It's why tire weight is very important. (Although you never hear anyone talk about tire weight, for some reason.)

This is one of the reasons the Tilton is so effective. Not only is it only 8 pounds, but it's significantly smaller in diameter than stock so all the weight is further in. However, this means you have to buy a clutch of same diameter. A stock sized clutch (such as the Nismo and JWT units) won't work with a Tilton flywheel.

Before you decide to buy a Tilton kit, though, be sure to drive one and see how you like it. It's *extremely* light!

 

RPS has a good reputation among the Z32 guys, but the flywheel they have for the Z33 seems too heavy considering the other options.

 

with the design of the RPS is it possible that it dissipates heat easier and rebuildable...or not a big factor?

 

I agree. Even my JWT flywheel (14 pounds) could stand to lose a couple more pounds. (Not too much less, though.) On that note, I suppose a lighter clutch and lighter crank pulley might help a bit, too.

 

For what it's worth, the JWT has a replaceable plate. (The plate that meshes with the clutch.) This means you can just swap out that plate rather than resurfacing like you might do with steel flywheels.

On the otherhand, I believe the JUN flywheel is steel, and it also 14 pounds. So, you could probably resurface that flywheel. I don't see a lot of people discussing the JUN around here, though, so I'm a bit short on info.

Regardless of the brand, I think anything heavier than 14 pounds might not be worth it. (Unless you get it for free or something.)

 

mmmmmmmmmmm tilton