Paul G

What is the difference between the stock $1300 flywheel, and the $450 Fidanza aluminum flywheel. Besides the price.

My 96 needs a clutch. Does the flywheel have to be replaced?

ToyC4

I'm doing the conversion to the Fidanza right now on my 92. There are advantages and drawbacks - so far it's a pita but my car's not back together yet so I'll withhold judgement and hope it's worth the 20 RWHP. The problem with the dual mass flywheel that comes stock on the car is that because of the dual mass design it can't be resurfaced so when you replace your clutch and the flywheel needs to be resurfaced you have to replace the flywheel. The other problem with the dual mass is that it's pretty heavy and it takes a few HP just to spin the flywheel so you lose RWHP. Does converting to a lightweight flywheel really give you 20 RWHP? It depends on the car. In a recent corvette magazine they took two ZO6 corvettes and dyno tested them before and after installing Fidanza aluminum flywheels. Yes both cars saw significant gains in RWHP between 15 and 30 I think it was because one car was modified and one was stock. Problems with the aluminum flywheel are that you'll have noise from the transmission, especially in neutral with the clutch out there will be a rattle. I bought a stage two clutch kit from Tom at Carolina Clutch which has a spung clutch disc that is supposed to help with this. If you search forums there have been several threads discussing pro's and con's of this conversion.
good luck!

bogus

Bad news, the sprung hub has nothing to do with noise absorption.

What the dual mass did was, due to it's size (ie, weight), absorbed the rattles better.

Inside the dual mass are 2 chunks of iron joined by a elastomer membrain. That membrain acts just like the springs in the sprung hub - which means, they are designed to absorb drive line shock, not noise. When you pull your old clutch out, you will see that the friction disk is solid.

I have the fidenza, the only downside, you MUST get the flywheels match balanced, this way, the new flywheel matches the balance of the old. You see, LT1/4s are internally balanced in the front (hense, no harmonic balancer to speak of) and externally balanced on the rear, the dual mass.

For example, when you buy a new dual mass, you get a set of weights, that are inserted into holes on the flywheel to match the balance.

The best solution is to rebuild the engine and get it internally balanced, which is what I am getting ready to do. Then, flywheels just need to be neutrally balanced.

Red Tornado

I bought the Stage II kit from same source, however mine is for an L98 which is externally balanced an required no extra balancing.

Although I don't know much power is being transferred to the wheels (not incrementally dyno'd, and all the other mods done at same time), what I can add is that you will rev faster....which is a very good thing. The downside is that the super lightweight aluminum FW will allow a rattling sound something fierce. Mine raises all kinds of hell, with the clutch disengaged. About 80-90% of the noise is eliminated with clutch pedal pushed in.....this is normally fine, however sometimes its not all that practical, so you deal with the noise (and do others at red lights).....at least during the winter months (ie, windows in cars are up), this becomes much less of an issue. Another thing I do is simply shut off the engine when I stop and have to get out of the vette for any reason.

I'll probably end up leaving the FW in there, since its too much of a hassle/$$ to covert it back vs. the only real "con" of excessive rattling noises.

Oh another "pro" the lightweight FW is that supposedly its easier on the bearings in the engine vs. the dual mass.

Hope this is useful

Paul G

I talked with several people today about the different clutches. The Fidanza aluminum flywheel does have a balancing issue when replacing the dual mass flywheel. The lighter weight of the Fidanza will let the engine rev up faster but I dont think I want to deal with the vibration and noise that come with it.

The extra cost of the dual mass flywheel is the killer. Most say it must be replaced with a new clutch. I found a shop in South Bend Indiana (which is a few hours from me) that has resurfaced them in the past. He says it can be done. That way I should not have a balancing issue. The idea of balance matching the Fidanza to the dual mass sounds almost impossible to me. How can you match the "off balance" of a 30 pound object to a 12 pound object? The best price I have found for the dual mass is around $600 from Carolina Clutch vs. almost $1500 from the Chevy dealer.

My plan now is to start taking it apart and see just how bad the dual mass flywheel is. If the flywheel is not to bad I will have it resurfaced and put a new clutch kit in it. If it is toast then I will order a new one from Carolina.

What do you guys think? Am I all wet with this plan?

rocco16

The balance can be matched because the "out-of-balance" factor of a flywheel is usually in the order of ounces, not pounds....and removing/adding ounces is not usually a problem.
My GM shop manual describes the dual-mass flywheel as two separate components that can rotate independently of each other, separated by coil springs. Some people are in the belief that a fluid is involved such as in a Fluid-Damper harmonic balancer, or an elastomer is involved as is the case of a stock-type harmonic balancer. According to GM, neither is correct.
A light flywheel does not add horsepower or torque to an engine. It simply lets more of that power go to work accelerating the car, instead of accelerating extra flywheel mass. A chassis-type (inertia) dyno will show an increase in measured power because it measures how quickly the car can accelerate the rollers, and a light flywheel allows quicker acceleration. A water-brake dynometer will not indicate an increase because it measures steady-state power production.
In short, a lighter flywheel would enable the car to accelerate quicker because of less weight....and less weight being accelerated in rotation, which takes power. But, it would not give the car a higher top speed because it doesn't add engine power (it just lets the car make more efficient use of the power it has).
Oh, yes, the DMF should only have to be replaced (when the clutch is replaced) if the DMF has been damaged. If it's in good shape, there would be no reason to replace it.
I'm getting..very....sleepy.....nooooooowwww w.....

Larry

lone73

I have the Fidanza Aluminum in my '96 CE. I have about 15K miles on it. I didn't notice any difference in switching over to it but I'm not a racer either. The big difference is in the noise with the clutch out. Rattles so bad I tell people I got the deisel vette option. It really does sound like a diesel motor on my car with your foot off the clutch.

I tried resurfacing my old F/W also. No good. Got the Box-'o-rocks noises bad after about 2000 miles. If your car is a driver there is no advantage to the FIdanza IMHO.

I DID listen to Joe90's car before I bought my Fidanza to try to get some idea of what I would be hearing. His car had loud pipes but I really thought I could live with what I heard from his car BUT he had a steel F/W from a Camaro - shaved down to work. I think the steel is the way to go. I am guessing but it appears the higher mass of the steel camaro F/W doesn't produce the same level of noise as the aluminum. I will probably switch to that eventually.

good luck
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LD85

I bought the Centerforce single mass conversion flyhweel for $320, which saved me from using a Dual Mass flywheel.

In nuetral the box o rocks noise is loud, but while driving I cant say that I hear noise,, but my car is a little loud.


My 85 flywheel weighed 15 lbs, the new Single Mass flywheel 30 lbs. I have to rev the car a litttle higher to get the car to roll but after it gets going it does not appear to be any different than it was with the 15 lb flywheel.

I do think the addittional FW mass smoothed out some of my 3000 rpm tuning issues, because the studder that I had at 3k RPM is gone now, after the new ZF clutch and SM conversion was done.

HammerDown

Either I missed it, or no one bothered to ask, but how many miles are on the flywheel?

Anything under 80k and I wouldn't touch it (the flywheel, that is). I've been through all of this already, and it's expensive as well as being a ginormous pain in the ****.

Paul G

22,000 miles on the car.

bogus

duh. great question...

and with the answer of 22k, unless it's been raced a LOT, I would keep the flywheel...

I guess this begs the next question, why a new clutch at 22k miles? That seems awfully low... rear main seal leaking? If so, that can seriously damage the dual mass flywheels elastomer membrain.

Paul G

I'll explain. I bought the car last month from a couple in Texas. It was the lady's car. The clutch felt like it was releasing late so I figured she rode it quite a bit.

Last weekend my old neighbor took the car (and me) for a quick ride around the block. He was wanting to show off for his kids a little. He revved up the engine and left the corner quick. Either he was in second gear or never fully released the clutch. The clutch smoked. Ever since it stinks when I bring it home. It still releases late only now it stinks. Nailing the car in third gear from a stop will smoke the clutch badly. I would expect the clutch to grab and bog the engine in third gear. Right or wrong? I think it is toast now anyway. Until I get it apart I wont know how bad the flywheel is. The cost of the flywheel has me doing a little homework before I even start the project.

ToyC4

Nailing the car in third gear from a stop? I think that probably wouldn't do much to help the clutch at this point! no wonder you need a new clutch! The guy at my local race shop said he has surfaced the dual mass with no problem it just involves spot welding the dual mass together, surfacing, and then grinding the spot welds off.

When it comes to the lightweight flywheel adding horsepower it's obviously not going to add horsepower at the crank, but it is adding real horsepower at the rear wheels because removing weight from the drivetrain decreases the amount of HP which is normally lost in the drivetrain between the engine and the rear wheels.

... just my $.02

Paul G

Ya go ahead and laugh. What am I going to do now. Whats done is done. Thats what I think happened. He must have had it in second or third instead of first. That LT4 is a mean engine but I would expect a strong clutch to hold it back in third. Ill see how much meat is left on it when I get it out.

As for surfacing the flywheel I am concerned about making it thinner than stock. I would think that the amount of metal you remove would be equal to the amount of disc that you can not use next time around when the clutch starts slipping again. The disc will be thicker and worn out because the flywheel is further away if you get my drift.

I think that re-surfacing will be prefered over spending $800 or more on a flywheel now that still has life left in it. I put about 3000 miles a year on the car. If the new clutch with re-surfaced flywheel lasts another 50,000 I got an easy 15 years. Will I still own the car then?

Red Rocket

Had the GM Camaro flywheel, turned .090, and Mcleod street and strip clutch in my 396 LT1 for five years. Put the new Mcleod stage 3 disc and Corvette Pressure Plate set up in this week. The stage 3 disc is ceramic and Bronze metal pucks.

Decided to try a new approach to shaving down the flywheel to make the Camaro flywheel and Corvette PP fit this time. The shop added .130 to the PP throw out bearing by welding metal from the old PP to avoid shaving the flywheel. Always had the concern that the flywheel did not meet spec with the shaving. Rare, but some of these shaved flywheels have come apart.

New set up works great with no noise at all.