Flywheel inertia dynamics?

[spyderdrifter]

I'm trying to research more dynamic functions of our engines. I like learning about the actual engineering to these cars and more questions have been raised from my own researching and theories that have an impact on parts I choose for my build. I have an OEM flywheel, but have also been looking at lightweight ones as a possibility. However, I know that the flywheel's inertia has an impact on engine harmonics balancing just like the actual harmonic balancer. I want to know how big of an impact this is, and how much of a reduction of balance a light weight flywheel creates. Any help would be great.

 

[needbooost]

I would think it has very little effect on the balance of the rotating assembley, stock weight or lightened it would still have a more weight on one side of the crank than the opposite. One thing to consider is that a lighter rotating assembley is good for bottom end power(aluminum) alot of turbocharged cars come with heave rotating assembley (cast iron/sylicone) since it works good with high reving engines.

 

[spyderdrifter]

More weight being on the flywheel side I agree with, but the flywheel itself is balanced to the engine's natural harmonics. Therefore, reducing the weight not only reduces torque (someone correct me if I'm wrong on that), but also pulls the harmonics out of balance in between spark firing. The flywheel weight keeps this in check with its' momentum, making the rotation smoother.

Lighter is better for low end power, yes, but my future engine build is going to be geared toward increased torque too, which our cars have always lacked, and the higher RPM band (doing a 2.1L).

I want to know how far off it throws the balance so I can build to keep the balance in check, while increasing the low end power with a lighter flywheel. I will use a fluid damper on the crank too, but there has to be other areas to balance this all out.