Should I bother buying an aftermarket lightened flywheel?
I'll be converting to 5-speed right after new years and going with an I/C'd turbo right after tax season is over. I'd like to start buying whatever performance parts I'll need for the conversion so I can spread the expense over the next couple months.
Can I get some opinions?? I'm thinking ACT Stage 2 clutch but I am not sure about a flywheel.

Thanks for any light you guys can shed....


-Tony

The faster your car can accelerate, the more beneficial a lightened flywheel is. This is because the torque required to accelerate a flywheel (that would otherwise go to the wheels) is proportional to the flywheel's mass and to the rotational acceleration (T = Ia, as you engineers will attest to). So the faster your car accelerates up through the rpm range, the more torque the flywheel robs from the wheels.

And that faster you rev the quicker you get to full boost in a turboed car, so in realtion to what stephen max said you will be able to rev up quicker and thus produce exhaust gas faster to turn that nice lil hairdryer you plan to attach. So yes if you can afford the flywheel then I would get it. I know Cattman had a special on the fidanzas when the group deal Jeff92se had going on, real good price. Good luck

Will it even rev that much quicker and free up that much torque to justify the $300-$400 cost?? That's my real question. I don't have endless funds for these 2 projects, but I'd like to do it right the first time around.


Tony

That depends on your own priorities and pocketbook. It's way down on my list of mods, but it is on the list. I'm thinking whenever I have to replace my clutch (which will be a while, I hope) I'm going to max out a credit card and get the flywheel and a Quaife diff all at the same time.

Your twin Max4speed is getting a lightened flywheel and you know his dumping the all show no go attitude. Ask him to post his opinion about the ACT/Fidenza set up in a couple of weeks

Can't be twins when one has SC and other has Turbo

I was planning on getting his opinion, but I wanted some general forum input as well.

Tony

Now its "All Show AND GO!"

So far the stock clutch ROCKS! 100K and knock knock going strong. Fidenza is sittin in the garage.

still twins now both will be boosted one will be even the other odd. Youll see the video as soon as I go over his house and upload it to his machine

a yin-yang sort of thing, eh? Or maybe matter and anti-matter.

A lightened flywheel will only help in the lower gears when the tranny has a chance to accelerate quickly in a given amount of time. Correct me if I'm wrong but might it actually hurt in 4th and 5th gears since it's not storing as much energy as the stock flywheel when the acceleration is more gradual?? Same concept are heavy *** cars that are surprisingly fast at high speeds. Although they weigh more and are slower from a stop, their momentum due to their mass allows them to sustain higher speeds using less energy. Hope that made sense. Either way, I understand myself.

You are right about lightened flywheels helping more in lower gears when the engine is accelerating at a faster rate. The rest of your argument is, ahem, less analytically rigorous, to say the least.

Hey hey Mr. Mechanical engineer. So I haven't gotten into Physics III or Solids or any other hardcore engineering courses. I'm only in sophomore year of college. And besides, the more mass the more inertia, no??

your statement holds true if the flywheel is too light. The fidenza is lighter then stock but heavy enough not to mess with the upper RPMs. Thats why everyone thats driven or rode in my car now owns one. If your boosted or NA youll love the fidenza flywheel. If I had a choice between MEVI and fidenza? I go fidenza flywheel first. why? less stress to the engine and saves you some gas if you drive with sense.

You are right about heavier objects being able to hold speed better due to their inertia. And it is true that if two objects of the same size are falling through air, then the heavier object will fall faster because the inertia of the heavier object overcomes the aerodynamic drag better than the lighter object.

Eventually, though, if you have two cars having the same aerodynamic drag, it will be the car with the most absolute power, not the car with the most specific power (power to weight ratio) that will attain the highest speed, and that is because the equation of motion for a car at top speed reduces to Cv = F, that is, aerodynamic drag times velocity equals force. If both cars have the same drag, then the car making the most F has the higher velocity.

By the way, this simple equation comes from the general equation of motion, ma + cv + kx = F. Obviously with a car there is no spring rate, k, and at top speed acceleration, a, is zero. That leaves the equation above.

Wow thank you for the physics lesson stephen, I am reading the screen again not knowing a word of what you just typed out but it seems good j/k I got the gist of it

so what have we solved here? what is the verdict...does the drop in et's justify the cost is all I want to know....

also, if I do decide to put the fidanza on...is there anything I have to do to prep the surface...like clean it with alcohol or something like you do with new brake rotors???

I have a Fidanza and CLutchnet 6-puck sprung clutch.

It's awesome from 1st and 2nd gears on a hardcore run in the 1/4 mile.

BUT it does bog bad when driving daily....like when starting on a slight hill going at a slow roll I have to rev the engine to almost 3k to get the car moving.

I have a Fidanza I put on a month and a half ago. I love it! I drove a friend's 96 5-speed with the stock flywheel, and then mine immediately with the Fidanza, and it feels quicker. The revs fly right through. Also, the wheels just chirp through 1st gear without any launch nowat WOT. It can bog/chatter though when leaving a light, but I never have to rev more than 1500 rpm...even on an incline, so really it's not that bad. If you are getting turbo, I would definetely get this flywheel because it will make the car quicker assuming you put the power down good.

Personally I would say get the flywheel. It can do nothing but help it wont hurt your HP #'s at all. Also as far as the clutch I would say SPEC Stage II or III or ACT HDMM or Clutchnet Stage II or Exedy stage II.

Bruce