[xb-60]

Originally Posted by scottj

Yes, reducing the mass (inertia) of a vehicle by such a small amount would have little effect on acceleration. What’s being overlooked though is mass moment of inertia. Mass moment of inertia is the resistance to rotational motion. It is affected by not only the mass of the rotating object, but the distance of the mass from the axis of rotation. Because a vehicle cannot accelerate (linear) without the concurrent angular acceleration of all the rotating components, (tires, wheels, brake rotors, gears, crankshaft, rods, clutch, flywheel) the moment of inertia of these components must be included when calculating linear acceleration. If you could somehow gather the data, the math would show that for components rotating at wheel rpm, every 1lb reduction in weight is equivalent to approximately a 3lb reduction in vehicle weight. For components rotating at engine rpm the ratio is much greater, possibly 1:10. I doubt most people could differentiate between a 22lb and 28lb flywheel regarding acceleration, drivability slightly, acceleration no. I’ve run 55lb flywheel/clutch assemblies and I’ve run 14lb, 7-1/4” dia. flywheel/clutch assemblies. The difference in acceleration is very noticeable. I currently run a 28lb carbon/carbon clutch/flywheel assembly.

A good comment, Scott.
In my car's application, I'm also taking into account the overall gearing. The Toploader (WR) in conjunction with a 2.92 differential ratio is in effect equivalent to a five speed gearbox without a first gear.
Hence, my leaning towards a 28lb or 22lb flywheel.

Cheers!
Glen