Absolute_Zer0

Currently im trying to decide if i should go with a lightweight flywheel. currently my tC is all stock. i have a HID kit and a short throw shifter. I will be replacing my clutch with a staged one soon and im trying to figure out if i should go with a lightweight flywheel as well. when i built my honda civic i added a lightweight flywheel and there was a very noticeable difference. but with the amount of trq the tC puts down im not sure if itll be worse as far as traction goes.

Any thoughts?

bentheswift

It's 100% driver preference... the lightweight FW will get you close to zero gains in acceleration. The cost greatly outweighs the benefits.

Absolute_Zer0

well i know with the civic it actually did help with acceleration. dropping from a 18lb flywheel to a 7.5lb flywheel defiantly helped free up some of the little trq the honda engine made and helped put them to the wheels. on top end it was a very noticeable difference. the problem was on first and part of second it would have the tendency to wanna spin rather than keep traction. which is my problem here. i dont wanna have it where im just completely spinning. and with the amount of torque the tC has versus the civic is why im wondering if anyone else has one and can tell me if it helped, made worse, or no difference.

SR0529

if you want to change a FW, why not replace the stock crank pulley to the light weight crank pulley? it benefit more.

Absolute_Zer0

that was something i was thinking about doing but wasnt sure which would be best overall because ur getting rid of alot more weight with the FW

engifineer

A pulley will benefit about a million times LESS. Simple physics. MUCH smaller change in mass on a MUCH smaller diameter = MUCH smaller change in rotational inertia. Not to mention an undampened pulley has other detrimental effects over time.

A flywheel will have a larger effect on acceleration hands down, although not a huge one. The larger benefit is throttle response. Rev matching will be tons easier with a lighter unit.

The only detriment to reducing rotating mass is that while the engine speeds up faster, it slows down faster as well, meaning you will need to adjust your launch by applying more throttle. You will see some different in engine braking as well since you are reducing overall inertia.

And this has been explained over and over on this forum (thought most ignore it), but it frees up 0 power and 0 tq. True power and tq are measured at steady state engine speed (not while accelerating) where rotating mass has no effect. If you put the car in gear, held it at a certain engine speed, and measured how much weight it could drag, there would be no difference regardless of rotating mass. It only helps a bit in acceleration because you are changing the moment of inertia, which means you are changing how well it resists changes in engine speed. Many dynos inherently measure power incorrectly, aka by measuring how fast it can accelerate at a given amount of load. While you are measuring something that way, it incorrectly shows that power change is the cause of the acceleration change.

Absolute_Zer0

thats what i mainly figured. not really a massive boost in accerlation but u can maintain that level over a longer time frame. meaning ur dont loose ur accerlation as fast at higher speeds. my problem though still seems to unanswered (minus the braking problem). what is the effect of the lightweight flywheel just daily driving. does it make it considerably harder to drive with the freeing of the torque.

engifineer

It doesnt free tq. It reduces the momentum of the engine, meaning it is easier to reduce engine speed. So, when you are taking off from a stop, you are going to want to apply more throttle since the engine will want to bog easier. One reason that they use a heavier unit from the factory is that it makes launching a bit easier for some, since it reduces the tendency to bog out and stall.

It will also make the engine speed drop further during a shift, which you will need to get used to.

Absolute_Zer0

yeah i see. thanks for the help.

my06tc

iTrader: (2)

%100 correct.......

SoccerBoy_AP

If you want an easy weight reduction and performance enhancement then do the lightweight pulley.

I wouldn't mess with your transmission unless you get boost or lots of natural hp.

Vlad1024

Correct me if i'm wrong but i don't see a point of getting an aftermarket clutch unless you're boosted.

SciMeiji

Actually import tuner proved that lightweight flywheels really do free up torque and horsepower TO THE WHEELS. Theyre integra gained 8whp and 8lbft:

http://www.importtuner.com/tech/impp...ion/index.html

IMO this is an incredibly worth while upgrade. When my transmission was being replaced i had the dealer install a fidanza 9lb aluminum flywheel and a CM stage 2 kevlar clutch. I immediately noticed a difference in response and power. This was no surprise. But my biggest worry was if my car would become annoying to drive considering revs fall a little quicker. No worries. It took less than a day to adjust and after that the car felt easier to shift and much smoother. Im supercharged so ur results may vary slightly but i in no way have had any type of wheelspin issues and i drive hard my friend.
If ur gonna do it dont go half a ss and get a 12lb-er go all for the 9, fidanzas the way to go.

Vlad1024

NO!

toeveryhour

iTrader: (3)

i put in an exedy stage three and an f1 flywheel simply because i ran out of funds, lol. but it does the job. i always have to get used to it every time i drive my car coming from a stock transmission DD, but it only takes a few miles then i'm good to go. only reason i put it in is because i went F/I. seeing as how my clutch needs replaced soon on my 350z, i'm just going to go oem and leave the flywheel alone considering i don't track the car nor really care about the #s it makes.

SoccerBoy_AP

Short answer... until you go with a F/I application, you don't need the heavier duty clutch setup.

Longer answer...
Swap to a lighterweight flywheel ... yes
This will reduce the amount of power the engine has to apply to the drivetrain in order to get you moving. Same physics application as swapping to a lighterweight pulley, less weight spinning = less drag on the engine.

Swap to a heavier duty clutch ... no
Changing your clutch should only be needed when you are trying to apply higher amounts of torque to your drivetrain. The stock clutch should hold just fine until you get above ~220hp/tq (correct me if I'm wrong), then you might want to look into a replacement.

SciMeiji

Cool man, you go with him. And ill go with import tuner. God knows theyve only been doin this for decades on 1000s of different cars. If the dyno shows a power increase then ull have that power increase on the road as well. Flywheels are not exempt.

"Lightened flywheels reduce the amount of energy produced by an engine that's spent in moving its components (parasitic loss). Since flywheels are solid, unsprung components of a vehicle's driveline, a lightweight flywheel will decrease parasitic loss at a constant rate, improving a vehicle's horsepower and torque output (measured after the flywheel) throughout it's entire rev range."

Vlad1024

Ok, lets talk physics. Your engine produces power(energy per unit time) and by conservation of energy it has to go somewhere. Some of it is lost(wind resistance, friction in the drivetrain, and the rolling resistance of your tires) and the rest of it is stored. It is stored in 2 ways, rotational momentum in the drivetrain and the linear momentum of the car moving. By reducing the weight of the flywheel you effectively reduce the moment of inertia of the drivetrain. So in a way they are correct(don't take this out of context). However, when you compare the mass of the car to the change in moment of inertia because of the flywheel the change is NEGLIGABLE. The amount of energy stored in the movement of the car is much greater than that stored in the flywheel. The advantage of the flywheel comes in when you revmatch because the momentum of the car is not a factor. Because the moment of inertia of the flywheel is smaller less energy is stored in it when you blip the throttle and thus the engine revs faster and the opposite applies when you upshift.

Import tuner got their results because their dyno is not able to reproduce the effect of the car's momentum. Because the rotating mass is much smaller the effect of removing several lbs is amplified. As was stated previously, there is no difference of power or torque in a steady state(as measured on an eddy current dyno).

If anybody has corrections please post them. I would be happy to learn something new.

Absolute_zer0:Unless you're going to boost stick with the stock clutch(maybe add a clutch stop) but i would defiantly reccomend a lightweight flywheel.

SoccerBoy_AP

http://www.physicsforums.com/archive.../t-160968.html

There is some math/physics for you to chew on....


Also:

Pulled from http://www.physicsforums.com/archive...p/t-52827.html (7th post down)
lordinfamous
Nov16-04, 07:39 PM
Speaking from experience and extensive no-how with cars, i can tell you that an lightweight flywheel wil give you know measurable horsepower gains and your torque will stay the same thru your torque bands. The only thing that wil happen changing to a lightweight flywheel will due is help improve your launch times. (REDLINE faster).

Vlad1024

Mmmm. Physics. I guess you could see marginal improvements in first gear because the flywheel is accelerating much faster than the car. However the first link misses my point completely. You should think of the car itself as a giant flywheel. Removing several lbs from the flywheel would be equivalent(and this is a educated guess) to removing 50lbs from your car. One again negligible unless you isolate the engine and flywheel.