lightend flywheel = is it worth it
 

im upgrading my clutch to a sports exedy one for when my car gets turbocharged soon. I was just wondering and wanting to know whether it would be worth buying a lightend billet flywheel for it as well or should I just stick with the standard flywheel as it can still do the job of holding boost efficiently enough? would it be worth getting a lightweight flywheel? i have an na6.

yes hella worth it. Love mine. :) Get a 1.6 fidanza.

I love mine. My 94 R had a fidanza that I loved and my current '90 has an unknown brand that rocks (Feels much lighter than the fidanza was). Lighter flywheel lets it rev faster and throttle response feels much crisper. The only downsides are that it becomes much easier to stall the car, and if you suck at rev matching shifting won't be clean. The plus side to this is that it encourages better driving habits.

This thread may give you a bit of insight.

I still haven't installed my new clutch yet, so I don't have any personal experience to add.

I decided to save my money and put it somewhere else on the car. Its probably nice to have though, but i just dont see it as something to buy until you are going for that last tenth of performance. Of course i might change my mind if i had one.

I liked it NA, but quickly got used to it and barely noticed it after a while. After going turbo it appears to make even less difference. The additional drive train noise was expected but not welcome.

If I had to do it over I would have saved the $$$ and invested it someplace where it would be more noticable.

After reading some of these posts and the ones in the other thread it seems like people were hoping the flywheel would make their car faster... it won't. It just makes it much more pleasant to heal and toe, and throttle response will feel much crisper. If you are doing the clutch anyway I recommend it.

i thought that removing the weight from the driveline was suppost to give you quite a bit of help in acceleration?

I love mine. I dont really notice a real difference in speed, but I love the revs and rev drop off

you feel it in the first two gears.

Maybe NA but not turboed if you're making any decent hp unless your buttdyno is hypercalibrated.

I installed mine while turboed and didn't notice much of a difference.

Frank

Incorrect. Flywheel will make the car accelerate faster. Removing any mass from the car will improve acceleration, removing rotating mass (flywheel, wheels/tires) is even better.

What won't show is an increase of HP/Tq on the dyno, which a lot of people seem to think is true.

that's the impression i've always been under also. while you may not notice it but so much, there are performance benefits.

How much can you lightin a stock flywheel safely?

If you can feel the difference in acceleration with a lightened flywheel on a boosted miata your butt is much more sensative than mine. There will be no appreciable difference on a dyno and 1/4 mile times really won't change. In my book that means that the car is not faster. While I agree that your argument is true about less weight making the car faster, if it cannot be measured or felt what difference have you made?

:dunno: they took 5 lbs off mine, and there's still plenty of meat on it everywhere

the lightened wheel does make the engine accelerate more quickly (and decelerate more quickly as well). It makes rev matching easier, and also is more forgiving if you didn't rev match.

the downside is you carry less inertia, which would make working the clutch a bit more "tricky" in certain situations, if you are inexperienced with a manual. the other downside, particular to the miata, is some increased driveline noise.

You can not measure the effects on a dyno, because it does not increase HP/Tq.

I have no idea how much it will change a 1/4 time (since I don't care about that). But someone has done 0-60 testing (from m.net) and has shown that there is a measurable difference. When my car was NA it felt faster in certain circumstances, especially while autocrossing. The car seemed to have more go when down low in the RPM, another Miata driver remarked the same thing when I let him do a fun run in my car. So it CAN be measured (0-60, 1/4) and it can be felt.

That was NA. Like I said in my few posts on the subject I don't think it is worth the expense and issues for a FI'd car.

I'd rather spend the $300 on coke and whores.

you can measure the effect on a dynojet. dynojets measure horsepower by measuring how fast you can spin up a drum with known rotational inertia. if the total rotational inertia of the system decreases (system = everything that spins, your crank, flywheel, clutch, transmission, driveshaft, diff, axles, wheels, tires, the dynojet...), then the dynojet will register that you have more power.

http://hyperphysics.phy-astr.gsu.edu/hbase/n2r.html#n2r

I is fixed. if alpha increases, tau (torque) increases proportionally. and hp is just torque x rpm / 5252.

and that's why dynojets are lame. they measure work over time... and allow you to change time.

I stand corrected, I was under the impression that acceleration had nothing to do with hp/tw meassurements on a dyno. Thanks for clearing that up. Still, the weight of a flywheel does not increase or decrease hp/tq :)

Is that just theory or have you seen this in practice? I wonder what kind of difference we would see?

I thought SCC did some measurements a while back. beyond that it's theory, but very solid theory. you can test it by revving the engine too. the load is much lower but if the car revs faster in neutral then it's the same effect.

the difference is probably pretty small. if I knew the rotational inertia of the stock flywheel I could compare it to my twin plate setup since I have numbers for that and give you a rough increase based on math and theory. Anyone got em?