I'm looking at getting the Fidanza 8lb flywheel for my DD (I/H/E + VAFC dyno-tuned). Are there any negative effects of installing it? Would there be any problem mating it to an OEM replacement clutch? Anyone know a site selling them for less than $155 shipped?

 

only con for me with the act 11lb. was learning to drive with it....you tend to dump the clutch and kill the car alot ....the lightened flywheels allows the car to lose rpms really fast apposed to the heavy stock one.....its worth it though....go with an act

 

on other hondas, when you turn on your ac, it can make the car stall

 

(I fixed your grammar)

I thought the main idea behind the lightened flywheel was the ability to rev quicker due to less strain. However, it does make sense that you would also drop RPMs quicker, as well. So knowing that, I assume the car will not coast as long as one with a stock flywheel? Does the reduced strain negate the lack of coasting ability in terms of gas mileage?

Why go with an Xact 12lb flywheel when the Fidanza is only 8lbs?

 

it's all about inertia. less rotating mass will spin up faster, but also carries less inertia, so when you depress the clutch, you will drop rpm's faster as there is less counter-force on the rotating assembly. this will also increase the effects of engine braking.

as far as coasting, are you talking about dropping your car into neutral and how far it will coast? theoretically, yes, it won't coast as far with a lightened flywheel as there is not as much inertia driving the drivetrain forward once you stop accelerating. however, i would think the effect of the flywheel would be minimal in this case, and much more dependent on your car's inertia, which would include aerodynamics, wheel weight, rolling resistance (tires), etc.

i would be curious to hear more comments on weights of flywheels and driveability. as with all things, there are obviously trade-offs.

 

I have the competition clutch 12 pound Street flywheel, and its perfect. Has all the stock characteristics, but the engine does rev quicker. And the car doesnt die in neutral. Stock flywheel is about 17.5 pounds. I think really a 8 pound should just be for race applications.

 

i have a fidanza 8lb flywheel for daily driving and yea i took some time to get used to it but once you do its awesome.. rev matching is super easy.

 

I have an 8lb one too. Not much different. Revs faster, loses rpm sorta faster but mostly like stock to me.

 

youd think lightened flywheel or anything that lightens the drivetrain assembly would reduce torque. Torque is derived from rotational mass an innertia I believe, so havin gless weight on the fly wheel should reduce torque a bit shouldn't it?

 

I also have the Fidanza 8 lbs installed with ACT HD clutch as a daily driver. The rpm does drop a little faster in between shifts, but there's no signs of engine stalling coming to a stop even with AC running. Also, no sudden drop in rpm while coasting in gear and letting go the gas pedal. The rpm does climb quickly if pressing on the pedal again, even in 5th gear. It took a little time to get used to the new clutch and the faster rev to find the enagement point in 1st gear (not bad at all). After that, it's absolutely fun to drive.

The installation is slightly tricky due to the tight clearance of the mounting area. I had to heat up the center mounting area on a hot plate in order to lightly press fit it onto the crank (it's one of the recommendations that came with the instruction). HTH.

 

thats good to know, i just got one second-hand and didn't know about that

did you lock-tite your flywheel bolts in? thats one of the things i'm deathly afraid of with an AL flywheel, but i was told if they were lock-tited in, that they would be fine

 

that's an interesting theory question. you are supposed to gain hp by eliminating some of the reciprocating drag, and since hp is merely derived from torque, theoretically you aren't losing torque, but gaining it. inertia, i believe, is simply the ability of an object to continue exerting energy (torque in this case) once a force has stopped acting on it. extra rotational mass won't create more torque when it's being driven, it will simply create more inertia once there is no more force being applied. the opposite is also true, in that the heavier the mass, the more force it takes to get it spinning and the part i don't know, but assume, is that it also takes more force to keep it spinning once it is in motion.

 

I've got an 11lb flywheel with an Exedy OE clutch. Works fine, RPMs do drop a little faster. Car does not stall with AC on at idle but idles just a little lower when it first kicks on, but picks back up. On a Mustang dyno, I made 137HP and 138TQ, so if I lost torque, it probably wasn't much

 

that is the exact reason i run a stock flywheel..... i have been told this for years...

 

http://en.wikipedia.org/wiki/Torque

misinformation is a bitch

 

i'm assuming what you are getting at is that the momentum of an object has no bearing on the amount of torque an object makes, yes?

 

Apparently by what wiki said is that Weight has no bearing on torque whats so ever! The only real important factor is the diameter of the load (length of the lever arm or size of pulley) is what I'm getting from reading that.

Anybody can post a link though, explain how that applies to our situation to help me better understand than. Our force is the motor's force being driving to the crank shaft or wheels how ever you want to look at it. So whats the lenght of the lever arm or pulley or the other variable in that equation? Our tires?...minus drivetrain loss and resistances as well as all other losses I can't even account for?

 

if you torque to spec you should'nt need lock-tite. i have been runnin my 8lb fidanza fw for 2000+ miles with no issues. but lock-tite can be used for that added assurance that it wont fail.

 

Ok, since no one has answered my question, I'll ask again. Why get the ACT 12lb flywheel over the Fidanza flywheel? Obviously, the Fidanza is made of aluminum and cannot be resurfaced. So you have to replace the plates. What's that cost? The ACT can be resurfaced but weighs 4lbs more and costs $150 more.

 

The theory about torque lost through a lighter flywheel has less to do with torque in general as it does with peak torque. Peak torque is something you'd want with a FI'd car since you're pushing enough power to rotate the crank in boost much more forcefully than in an N/A car. for a N/A car you want less resistance so you can reach your peak faster, whereas for a FI car you want to hold the peak longer.
For street use you shouldn't really need a 12lb, but I had an 8lb and it was DD-able. The only thing is if you engine brake it feels like you hit a wall, I didn't notice a difference in coasting at all.

 

0_o

 

coasting in neutral* my bad

 

i was mostly just stating the TQ has nothing to do with inertia, its an ideally isolated event. torque originates in the crank, your lever arm is your crankshaft.

read this page, and also click to "how a flywheel works"
http://www.uucmotorwerks.com/flywhee...orque_loss.htm

they explain it better then i can, and without a tired brain mixing up his physics

but they also explain why people say TQ is lost, and its because of the drivability. since its easier to stall, people think that it has less TQ, but that just isn't the case

 

*shrug* i passed physics once, i don't want to try my luck a second time. haha

My general point was that
FI = better w/ heavy flywheel
N/A=better w/ light flywheel

why? FI = can use the stored inertia (correct term?) and keep pushing
FI + light flywheel = peel out left and right

N/A + stock flywheel = stock and slow climb to higher RPM's
N/A + lightened flywheel = less drag

 

FI+light flywheel+grip=w1n?

thats like putting heavier wheels on your car so you don't break traction...