Flywheel

Enzio · Post by **Enzio** » Mon Aug 04, 2008 10:34 am

Hey guys,
I was wondering how many of you use lightened flywheels? Do they work well with the CA18 and if so how much lighter than std should it be?

HancoB · Post by **HancoB** » Mon Aug 04, 2008 10:41 am

Uhm...well that wont make sense to me since the CA18DET already have no torque below 3000rpm, and then getting a lighter fly which means that it needs more revs to make more torque...so if i'm thinking right here it will mean that you have to pull away at every traffic light in boost????

Gary??
VC??

What do you say?

Gary57 · Post by **Gary57** » Mon Aug 04, 2008 10:53 am

Yes the CA18 have no torque. My flywheel is so light that I have a lumpy idle below 1000rpm, its idles at 800rpm but at 14:1 AFR. Yes the lighten flywheel makes the motor feel gutless but definately makes it rev quicker. I would still do it every day of the week.

Enzio · Post by **Enzio** » Mon Aug 04, 2008 11:12 am

So gary, how much lighter is your flywheel than std??

Trance101 · Post by **Trance101** » Mon Aug 04, 2008 11:24 am

I got my flywheel lightened and it makes quite a difference. Sure you sacrifice a bit of low down torque but the motor just love to rev with the lightented fly wheel. Good mod I think. Mine is 3kg's lighter.

Gary57 · Post by **Gary57** » Mon Aug 04, 2008 11:28 am

Mine is about 5Kgs off hey, I could find someone who would remove that much from Trance's, everyone said its not safe.

Doctor G · Post by **Doctor G** » Mon Aug 04, 2008 12:26 pm

how much does a std ca18 flywheel weigh?

Any less/more than a SR flywheel?

I'd love to see a back to back dyno chart. I don't totally buy the loss in torque theories when it comes to lightened flywheels...

HancoB · Post by **HancoB** » Mon Aug 04, 2008 12:42 pm

Its kinda true hay, there is a loss.

Ask Gary, its got a lot to do with Rotational Kinematics and Rotational Dynamics and momentum.

Basic Physics.

Gary57 · Post by **Gary57** » Mon Aug 04, 2008 12:58 pm

A flywheel doesnt make torque hey, it just retains it. So you will feel less torque when you going say up a a hill, so just put your foot down a bit more.

You will have a drop in torque because when the motor falls off its torque curve the flywheel doesnt have enough inertia to release so you feel a drop in torque.

HancoB · Post by **HancoB** » Mon Aug 04, 2008 1:04 pm

Lets make it easy for them to understand, its like a pendulum without the weight at the bottom, then its not gonna move from side to side or if it does its gonna move a little and a lot of force will be needed to move it.

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Mon Aug 04, 2008 1:27 pm

Lets make it easy for them to understand, its like a pendulum without the weight at the bottom, then its not gonna move from side to side or if it does its gonna move a little and a lot of force will be needed to move it.

Agreed lets make it easyier, Thanks
http://www.geocities.com/motorcity/7177/flywheel.html

accelerating a vehicle the engine not only has to push the total mass of the car but the internal components of the engine need to be accelerated also. This tends to absorb more power as the extra power is used accelerating the internal mass of the engine components and is why a motor accelerating on a dyno will produce less power than at constant revs. Also it must be remembered that the rate of acceleration on the engine internals is much greater that the rest of the car. This would then suggest that by lightening the flywheel, less power would be required to accelerate it and therefore more power would be available to push the car along.

Now, it may seen unbelievable that by removing a few kilos from the flywheel a noticeable difference to a 1000+ kg cars acceleration will be made. In fact the difference is quite noticeable and the secrete behind this is hidden within the gearbox. Everyone knows that cars accelerate at a greater rate in low gears, this is because a cars gear box basically a mechanical leaver and just like when using a leaver to lift a heavy object, the gearbox reduces the mass of the car that the engine sees. For example, in first gear an engine will see the cars mass as only around say 100kg but the engine internal mass would still remain around 20+kg .

It is now easier to see were the extra performance comes from when you lighten a flywheel. In some cases, and not necessarily extreme ones, you could effectively " lighten " a car by 20% in first gear just by removing mass from the flywheel. As the gear used increases this "lightening" effect is reduced. This is why carÉs acceleration reduces in higher gears, to almost no effect in top gear. Great for drags and tight race tracks but will not increase a cars top speed one bit.

For the engineers among us.

http://www.physicsforums.com/showthread.php?t=160968

HancoB · Post by **HancoB** » Mon Aug 04, 2008 1:37 pm

The post master is back

mario_200sx · Post by **mario_200sx** » Mon Aug 04, 2008 2:00 pm

CA18DET weighs in at around 13kg, correct me if Im wrong. And I believe the SR flywheel is lighter, dont have a exact number for the SR20

Gary57 · Post by **Gary57** » Mon Aug 04, 2008 2:05 pm

Yeah I also think its about 13kg, TOO damn heavy I know that.

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Mon Aug 04, 2008 2:07 pm

The post master is back

I just couldn't stay away.