Lighter flywheels

[djprescott]

What are the benefits of a lighter flywheel?

[English Ford]

A flywheel doesn't actually 'absorb' power as such, so lightening it would not produce more power (bhp) ate the wheels.

What fitting a lightened flywheel does is to reduce the inertial weight that the engine has to spin and therefore allows the engine to 'spool' faster.

This results in increased acceleration because the engine gets into it's power band faster.

If you are just looking to make power the flywheel is not the place to start looking, but if you want to use the power it's a good modification.

[djprescott]

Thanks for the answers.

Does that mean that a low weight flywheel will give the characteristics of the engine revs dropping slower when engaging the clutch, as opposed to a heavier flywheel?

[homer75]

Lightening the flywheel will have the effect of making the engine more responsive due to less inertia caused by the weight of the flywheel. It will, as English Ford has said, reach its optimum power band faster. The engine will accelerate and decelerate more quickly. Basically it will become more 'zippy' but the power output will not be affected. However, by the time you start thinking about lightening the flywheel I would assume you would have carried out all the mods to increase the power output of the engine.

[djprescott]

Homer, i am not planning to do any mods to the engine.

I have a Nissan 350Z and the 06 model has lighter flywheels and I just wanted to hear what benefits that might bring.

[homer75]

Hi djp -- I'll bet the new one has better 0 - 60 figures for acceleration

[djprescott]

Yeah, fractionally by about .1 sec!!!

[scotstone]

Acceleration is dependent on torque rather than power and torque is required to continually accelerate the flywheel up to speed. The function of a flywheel is to store energy which is returned to the engine on non-power strokes. The amount of energy stored by a flywheel is dependent on its moment of inertia which is a function of mass. So reducing the mass of the flywheel will result in more torque available to the driving wheels hence greater acceleration. The downside is less energy storage in the flywheel resulting in a greater fluctuation of rotational speed and a less smooth engine. Maximum speed is dependent on power output.

[Toureman]

Probably the difference in weight between the newer model and yours is very small. the weight of flywheels is carefully calculated by the manufactuer.

The ultimate lightening of flywheels is of coures on the F1 cars but because there is no inertia in the light fly wheels the revs at tickover are about the same as your car at maximum revs!

[cyclone]

djprescott the revs will drop faster with a lighter flywheel, they will also rise faster, the engine will feel more responsive basically, as you say 0-60 times will be largely unaffected but if you need to blip the throttle, on down shift for example, then you will be able to do this much more effectively.