Help explain to me the understandings behind running an iron flywheel compared to an aluminum flywheel (or vice versa) in a street car and or drag car. An iron flywheel (21lbs for example) will help a car get off the line better from a launch compared to a lighter flywheel (11lbs for example) right? Because of rotating inertia? Kinetic energy? I assume a lighter flywheel is better for acceleration once a car is moving right? I have also read of some that swap to an aluminum flywheel have to usually give it a bit more gas feathering to get off the line in everyday driving because the rotating inertia isn't as great. Does that make sense? Does to me. I read somewhere in a magazine that the diameter of a flywheel (to a point) has more of an effect on the rotating inertia than does the composition of the flywheel? Any formulas? Ideas? Thanks for any feedback or corrections!