frankhez

Has anyone out there put one on, and if so what where the results. The claim is RPMs come quicker due to the lighter weight (which is understandable) but I'm curious about any actual owner results.www.fidanza.com is thier site.

jimman

The transmission keeps you in a narrow rev range and the stored energy from a heavy flywheel is there when you shift rather than bog. Can't get traction as it is so why make it worse.

SpinMonster

I have it on both my C5 and C6. The revs are three times as fast. There are no launch problems. Phil97svt is near 9's with his fidanza/ram set-up on stock displacement. On the street he and I both have a smooth engagment into gear and you can drop the cluth with et streets at 6k and it hooks.

One again like gears, stay away from comments from those who don't own them. The truth is that less rotating mass is good for any engine. If it helps revs out of gear, it helps in gear. There is no difference in clutch engagment at all and there is no bog in any gear at all. The engine doesnt need any additional rotating mass, its just too expensive to use an aluminum flywheel from the factory.

I used the C5 set-up on the C6.

Jim, this is not directed at you. You are obviously very intelligent and have opinions/theories that are sound. I suggest that maybe there are just variables at work that you haven't considered to explain the difference betwwen theory and observed performance.

jimman

It's fine for a 1st gear do to a wide rpm spread, but it's when your in your staller gears when the spread of rpm is narrow. For road course and circle track ok but for drag racing no no. Discoverd this 40 years ago and got an instant 4 tenths in the quarter.

SpinMonster

It been a very debated issue and no one on this board has observed your experience. A lighter rotating assembly is a good thing or people would be buying heavier assemblies. Its just 14 pounds the engine doesn't have to overcome. Everyone that tried them went faster in the 1/4, except now you.

The arguments against them went down as another myth. I respect your opinion.

C6RAPTOR

What is a good flywheel & clutch set for my C6? If I supply it my dealer will install it when they fix my 1st gear. Who has a good price?

MitchAlsup

I don't understand why you think a lighter weight flywheel is undesirable. For any point in the engine's operational range (except idle) the engine simply gets more of the energy of combustion to the rear wheels. First, the car acclerates faster because the whole car is lighter, then the engine spins up faster because the rotating weight (that moment of inertia thing) is less.

The only reason for big heavy flywheels is to make the engine idle with a nice smooth purrrrrrr, and one can reduce flywheel weight quite markedly before the engine starts shaking enough to bother a die hard car guy at idle. With headers and freeflowing exhausts, you will hardly notice the vibrations anyway.

However, radical changes to the flywheel weight will also the resonance frequency of the crankshaft and might require a different mass damper at the nose of the engine.

WhiteDiamond

Although it was not a Corvette, I put a much lighter clutch and flywheel in a LS1 equipped F-body several years ago. I got the same type of comments from people and the real truth of it was the new clutch and flywheel save just over 20lbs and it drove just like before I had the swap done. The engine also seemed more responsive in gear/out of gear and engine braking also seemed more effective. I would do it again.

Todd

jimman

Could be different with Corvette and weight factors. Mine was a 55 Chev 327cuin with close ratio 4 speed and 5.38:1 screw on 12" wide drag slicks. We launched at 8000 rpms and red lined at 9500. taking the al out and replacing with steel made a night and day difference in time.

SpinMonster

The wieght on the back of the crank is the entire drivetrain not just the flywheel. When the clutch is engaged the entire driveline is one piece with the rotating crank. Telling me any car runs faster times with heavier things attached to the driveline is idiotic. Parasitic losses are bad and there are uncounted mods to reduce such losses to get a car to run faster. As far as track cars go, I have a dedicated non street legal dart (for 22 years now) that has all these mods and is faster for it all.

The crank is zero balanced regardless what is attached to it. Unless something is out of balance where a fluid or hpi superdamper will benefit you....but it is just a bandaid for something wrong. I do believe in metal resonance being an issue over 6500. My dart crosses the traps at almost 10k rpms and a superdamper is awesome insurance. NOT because of added wieght but because of the dampening effect on resonance from slowing a wavefront. Throwing weight at a rotating assembly to make it smooth is wrong.

I don't feel like reinventing the wheel for every guy with a degree that wants to doubt every mod subject to his own testing on a near stock car (although I respect the energy of such individuals). Research these issues and make your own decision. You all must agree that some mods will have a vastly different value depending on the synergistic whole of what it is going to work with.

Making a judgement call on an air cleaner or exhaust because it only got 6 hp on a dyno is silly when you look at the value of those same two mods on a max effort 700 hp car.

shopdog

And vice versa, things that might make a significant difference on a max effort race car may only yield trivial, if any, gains on a milder street car. In fact, they can sometimes even hurt the driveability of a street car. A lightened flywheel is an example of the latter. While it'll certainly allow an engine to rev quicker, it'll also make it harder to ease off from a stop in heavy traffic without excessive slipping of the clutch.

SpinMonster

100%

I have an aluminum flywheel in both my C5 and C6 and there is no issue at all in engaging the clutch in first gear. I can engage the clutch without even touching the gas pedal. I bet a million bucks you never had one and I would love to know where you got this totally false information. Its posts like yours that started this BS rumor to begin with.

THERE IS ZERO DIFFERENCE IN DRIVEABILITY

jimman

I would suggest you look up the word “inertia” and study some physics before you continue to trash people. Also your statement earlier reving 3 times faster, please define, do you reach 60 in 1.3 seconds now?

SpinMonster

No Jim I don't get to 60 in 1.3 seconds, out of gear it gets to 7k in 1/3 the time. You know why?...less inertia. I do know about inertia but unlike you I don't brag about my college background but I do have a masters in math so don't talk down to me about definitions of inertia. Inertia blocks acceleration as you well know that a car (mass) wants to stay at rest and resist changes in acceleration....but you must be talking only about how it keeps an object moving that is already in motion. Well driving involves a car starting from a rest.

No a 3400 pound car is not advesely affected by a 14 pound drop and no the thrust of this engine is not hurt by the same. You are trying to sell that the power from a moving mass of a 45 pound rotating assembly being driven by the force produced in an engine is less than that of the same force driving a 59 pound rotating assembly. You claim you tested this yourself and so did I but I still have that car.

Parasitic losses make a car slower. 15-17% drivetrain loss, remember....of course you do....you even argue that percentage....well its less on a lightened rotating assembly. Heavy rotating assemblies are bad Jim. Thats why you buy lightweight components and manufacturers brag about how many grams they shaved off their pistons. Or should we all buy heavy pistons because inertia will keep them moving faster in the motor?

The combustion explosion moves the car not the weight of the components that are behind it. They reduce the power produced.

As for trashing people, if you post a statement like: it makes a car harder to get into gear or it hurts the driveability of a street car, I know from experience it isn't true and I get a little worked up. Chris from ECS called me 'opinionated'...he was joking and being polite. I am arrogant and appologize for my attitude. I like the discussion. You Jim are good at debating and I bet if we met in a bar, we wouls have hours of fun irritating each other over a few beers. Maybe one day....

I think one of the biggest things working against aluminum flywheels is that people invariably get one only when changing to a more agressive clutch and hence driveability changes.

jimman

Good debate but what I was trying to tell you is that the stored energy in the rotating flywheel is accomplished before the green light. As in my upper post we did a 8000 rpm launch with the al and we bogged because we had an awesome hookup with the weight and 15" rinklewalls. With the added energy of the heavier flywheel we came off like a rocket. You will also note with the transmission we were using we only dropped a 1.5K between gears and that small delta isn't going to be gained by the lower mass. The trust one got from shift to shift was awesome. We made over 300 passes with that car and a hundred was done with al and we averaged a .35sec improvement. Now with a light car probably not that big a factor. I also have some of the runs on video.

shopdog

Yep, the stored energy in the flywheel is key to why you could launch harder, and why in a street car pulling off from a stop is smoother with a heavier flywheel. Trucks are invariably fitted with heavier flywheels for just this reason. Tapping that stored energy at launch boosts engine torque just when it needs it most. Spinmonster is correct that a lighter flywheel will let the engine spin up faster. But that's a moot point when you spin the engine up before the clock starts.

OTOH he is right that less rotational inertia while accelerating in gear is an advantage. But when in gear, the entire drivetrain, drive shaft, tranny, diff, wheels, and tires are part of the rotational inertia, not just the flywheel. The flywheel is turning fastest, so its inertia has a disproportionate effect, but the mass of the rest of the rotating parts is so much greater that the effect of a lightened flywheel on acceleration in gear is modest. Going to smaller diameter wheels or lighter tires would have a greater effect.

The one place where it does have a profound effect is when blipping the throttle to speed match when downshifting. Then, with all the rotating load of the drivetrain removed by the clutch, the lighter flywheel lets the engine spin up faster so you can complete the downshift faster.

In my misspent youth I had a very vivid example of all this. I owned a 1971 Hemi Challenger. I had Warren Barnett (then the Hemi engine man) build the engine up for drag racing. He installed a Reed cam, 12.5 forged TRWs, a Hilborn fuel injection setup, and an eleven pound aluminum flywheel. The engine would go from idle to 6000 RPM so quickly when you blipped the throttle it was scary. But it bogged and bucked something fierce coming off the line. I was burning out NASCAR track clutches left and right trying to tame it. Then we went back to the factory stock flywheel. Huge difference in driveability, huge difference in launching the car at the strip. I also drove this thing on the street, and the heavier flywheel helped make clutches last because I could start off with much less throttle and much less slipping of the clutch.

SpinMonster

Interesting how we all have different experiences with the flywheels. Mine on the dart is a 426 hemi 13.5:1cr, 6.13's and 15" wrinkle walls on a shortened rear axle. I couldnt get the damn thing to hook until I went over the 6.xx mark on gearing.

I have to credit your experiences since you used the same clutch with the different flywheels. I switched both out and had limited experineces with experimenting on different combinations.

Current experiences are different on the corvette too. Phil97svt has the fidanza with the RAM 900 and is going near 9's on stock displacement and he had the same comments on the fidanza too....no different on the launch and they work well for drag cars. Since there is practical experience on both sides of the fence, I must offer that I could be wrong. I like the way my motor revs and performs on the street C6/C5 and since I only run street tires and I am grossly overpowered for that set-up, bogging from hooking isn't an issue for me. I guess I will take refuge in the fact that the reduced weight is great for the crank bearings. My corvettes will never get a roll cage and I will never run tires that kill the one thing I love most on this car: handling.

On a side note: Jim your car was awesome and I like the furry dice too...heh. Is that a ham or CB antenna in the back of the house?

Shopdog: You have the car I wanted but couldn't afford at the time.

Happy day though; I still have my sick dart.

If either of you have any launch videos that can be e-mailed I would love to see them. DETENTIONizOVER@yahoo.com

SpinMonster

Almost forgot: FRANKHEZ (since this is your thread), it appears that unless there is a dedicated drag car set-up on your corvette there is little to argue about the value of the fidanza flywheel. I would always get it.

jimman

I'll have to get creative, have them on VHS vs 8mm film. Can transfer to DVD and see if computer can sort it out.

HIGHRPM

It's physically impossible for your motor to rev three times faster with only a lighter flywheel. To rev three times faster you would have to reduce the total rotating mass of the motor, clutch and flywheel to one-third of its original amount. I had an aluminum flywheel and swapped it out for a lightweight steel unit. Under load there is no appreciable difference using a flywheel that is a few pounds lighter... save your $$$ for a mod that makes real power.