lightening flywheel

[graham kirkbride]

hi all
whats the advantages and disadvantages of lightening a c20xe flywheel..would it be a good idea, also i want to use my car on road/track/ santa pod and want the best performance possible my engine is 200bhp+ if this helps

[craig green]

A lighter flywheel isnt necessarily best for 1/4 mile action. Possible gains for track usage however. I would say have it lightened but not all the way, if that makes sense.

You can lose torque which is bad IMO.

[Sirnixalot]

im not sure on the lose torque thing but a light flywheel makes it hard to launch reliably at the drag strip, they dont store enough energy and the revs drop/car bogs so its either bog or launch roasting tires, though thats only with a really light flywheel and clutch combination.

[graham kirkbride]

so i would be best just taking say 1kg off it WOULD THIS SOUND ABOUT RITE

[Sirnixalot]

no need to yell, 1-2kg would be fine:thumb:

[graham kirkbride]

no need to yell, 1-2kg would be fine:thumb:

lol lol thanks all for the advice

[Chunky Lover]

Makes the car rev alot easier. and i do find she can struggle sometimes on uphill sections possibley cause of a loss in torque cause it cant hold it?

[Jon_nova1]

obviously if it was all good flywheels would be like that from the factory, you can lose torque, but that depends on how much you've had taken off, and how high the hill is your going up, you'd also have to practice your clutch control ;)

[stv-b16a]

cars fitted with a lighter flywheel tend to lose speed more easily when going uphill.

[Sirnixalot]

im having trouble trying to grasp that, if you are keeping a constant throttle this is highly unlikely to happen, if you change gear, the revs will drop the same as on a flat road......i need to do some more reading on flywheel inertia it seems

[stv-b16a]

two identical cars approaching a hill at the same speed,same gear and the same constant throttle. the car with the lightened flywheel will not keep that constant speed as easily as the car with the (heavier) standard flywheel. am i wrong?

[Jon_nova1]

no, your right, the flywheel basically has stored up energy in it due to the weight, this stored energy basically gives you better torque going uphill and better clutch handling etc,

when you take weight off the flywheel you are basically freeing up the stored energy taken to turn the flywheel, this is why you get gains, because the flywheel would have needed x BHP to turn it (which is stored power) so if it gets lightened then it'll need less power, so has less stored energy, which means the less power you need to keep the power in the flywheel, has gone to engine BHP increase

[Sirnixalot]

the flywheel stores energy, one with a large mass stores more, so keeps spinning longer once force is removed from it.

In the situation you describe the engine is providing the energy, the flywheel is not giving out its stored energy.

I have no experience with cars and hills (i lived on a very flat island), but swapping out to a lighter flywheel i do and i did not once notice my engine drop revs more than it would with the standard flywheel when it encountered a sudden load.

In my experience a lightened flywheel will only show drivability "negatives" when the clutch is disengaged/engaged or moving from a stand still. Once the car is in motion, the clutch engaged and the engine working the flywheel will make (to the average joe) little difference, the engine might progress through the rev range slightly quicker as there is less energy used on rotating the drive train and more of it making it to the tires.

[Sirnixalot]

hmm i can see that but im just having trouble accepting it lol lol \


btw an engine doesnt make more hp with a lighter flywheel, it just uses less on the rotating assembly, the power has always been there just trapped in a fat mans body ;)

[Jon_nova1]

i know, thats why i said the power is freed up :p

it depends on how much its been lightened and the incline of the hill, if you think when you go up a really steep hill and start losing engine speed, its the same, but the hill doesn't have to be as steep lol

[stv-b16a]

i think a lightened flywheel in a car with a nice big flat tourqe curve is probably goin to be a good thing. letting you rev free'er through the through the powerband. however in a car with less torque and relying more on mid range-top end for power it is not so good. as you need the flywheel to smoothe things out until you reach the higher revs.

again i could be totally wrong lol

im just talkin sheite now arnt i

[Chunky Lover]

Right iv just completed a full engine rebuild and main thing i was going for was torque, so along with the rebuild we lightened the flywheels so il tell ya how she feels tomorrow. might lose torque going up hills? or she might rev up through the gears easier? only time will tell.

[Jon_nova1]

on what engine?