Fidanza Flywheel vs Dual Mass Depth

[Torchred96]

I know there's a lot of Fidanza threads but I couldn't find what I was looking for.

Purchased a Used aluminum Fidanza which came with the pressure plate and disc that it had been installed with. Looks to be in great shape.

I noticed that the original dual mass and fidanza are different heights when sitting on the bench flat. So I measured the difference in width (front to rear) and there is approximately a difference of .120" with the fidanza being thinner (ring gear to face distance), that appears NOT to be from wear. I made a second measurement with both flywheel's clutch side down on the bench and measured the distance from the flywheel face to the front of the bolt holes (facing the block) and the difference was approx .080 which is a little better and probably the more applicable measurement since it measures the distance from the crank to the face of the flywheel no? But the question remains:

1. Will this difference cause a problem with clutch pedal travel and will I need to adjust or change out the fork pivot because of the difference?

2. The flywheel to crank holes are recessed/countesunk. I'm concerned that flat washers won't follow the contour of the countersink. Do you think that is a modification or is that the way they come from fidanaza?

I read many threads about bolts but I didn't see any addressing countersunk holes

thank you.

[bradley]

I would contact bill boudreau and see what he says 602 319 6575

[Dynomite]

Originally Posted by bradley

I would contact bill boudreau and see what he says 602 319 6575

And I would have the numbers ready so you (and others) know exactly which Fidanza Flywheel you have......

zfdoc

Fidanza (flywheel/clutch plate)
Unsprung clutch with Fidanza
Sprung clutch with Fidanza
Pressure plate bolts

Originally Posted by torchred96

I just may put the original flywheel back in for now because I'm not sure if I will tolerate the noise level having seen a youtube vid of a c4 with the fidanza and the rattle can noise.. scroll into the vid about the 2.00 min mark. I know it's not an lt5 but that's a lot of racket if it sounds ANYTHING like that, I'm out.

Yep.....me also. I should do some calculations of HP gain with the Fidanza during acceleration but just did not want to take the chance of introducing rotating mass vibration into the drive line so skipped the calculations

1. LIGHTWEIGHT FLYWEELS AND DYNAMIC HP
The way I figure it you use Dynamic Horsepower only during angular/rotational acceleration of rotating components. There is lots of other rotational acceleration resistance including wheel rotation, drive shafts rotation, engine pulleys rotation, crankshaft rotation, harmonic balancer rotation, (basically anything on the engine or driveline you are increasing the rate of angular velocity).

I included the Frisbee calculations (as an example of the calculations of angular acceleration HP) on an L98 for example which I did eliminate the Frisbee (just for looks and not for HP gain). The only way I could get any HP gain without the Frisbee was rev the engine in neutral

If you change to a Fidanza Aluminum Flywheel you will notice the revs in Neutral are a bit faster but under load I doubt you would notice a change in angular acceleration of engine rotating components at all.

Tech Info - L98 Frisbee Horsepower

Now given your maximum angular rotation acceleration (not including neutral which would be by far the greatest) would be in first gear when you drop the clutch and then accelerate from 3,000 rpm to 7,000 rpm the quickest. All other gears you are accelerating rotating masses (angular acceleration) much slower since you never drop rpm in a quick shift to near 3,000 rpm. In the higher gears you are pulling a much greater load and your angular acceleration of engine rotating components is much less for the same ZR1 acceleration down the road.

Anyway..........I was more concerned about changing the rotating masses of anything and potential vibration issues by introducing an out of balance of rotating parts. Just changing the U-Joint bearings in a drive shaft can cause vibration for example if they are shifted one way or other a fraction of an inch from stock installation.

Keep in mind also Marc Haibeck calculated a change to an aluminum Flywheel will get you 15 HP but that is DYNAMIC HORSEPOWER ONLY and cannot be added directly to the other HP gains from Porting, Cams, Chips for example.
See Dynamic HP Increase 15 Horsepower

2. GENERAL TECHNICAL DISCUSSION REGARDING DYNAMIC HP
Engine HP is Torque x RPM.......RPM in Radians per second and Torque in FT-LBS where 550 of that multiple is One Horsepower.

Dynamic HP is a bit different and depends on rotational acceleration of masses and concentration of those masses related to center of rotation of each mass.

Compared to reving in neutral, reving in first gear is much slower and reving in 3rd (1/4 mile top gear for most) is slowest time frame. You get to 7,000 rpm a lot faster in 1st gear than in 3rd gear.

Torque to rev a fly wheel is much less than thrust of tire on pavement multiplied by tire loaded radius.

When Marc suggest 15 HP......... that is variable depending what gear you are in and the resulting rotational acceleration of ALL rotating masses including water pump, alternator, drive shaft, pressure plate, crank, harmonic balancer, wheels......so lightening any of those masses will give you some additional Dynamic HP. And......depends how far masss from center of rotation with wheel being worst with mass of rubber on outer diameter.

I will do some Fidanza Flywheel experimental calculations a bit later but determining Moment of Inertia of rotating components is not easy and at what RPM is angular acceleration greatest and most degrading to performance in quarter mile for example.