Reply to "Flywheel Mass vs. Acceleration"

Chuck I agree with your logic entirely. Here's some additional food for thought.

There's three types of acceleration: (1) from a rolling start, or (2) from a dead stop at low rpm (stop light street racing, road racing), or (3) from a dead stop at high rpm (drag racing).

From a rolling start its generally the entire the weight of the vehicle. The vehicle acts as one.

From a dead stop at low rpm the clutch is the dividing line. Everything on the flywheel side of the clutch must have a certain amount of mass in comparison to everything downstream of the clutch.

In drag racing everything is made as light as possible, and tire traction, clutch slip/torque converter slip are juggled.

Very Important: In all 3 applications the larger diameter a rotating part is, the higher importance is plays due to inertia.

The explosive acceleration of a 351C 4V and the traction of street tires are at odds, and must be considered. My 351C 4V powered Mach I Mustang had a factory flywheel (and Shelby traction bars) and could take a Ferrari Boxer or a Countach from a stop light (as I proved on several occasions back in Long Beach in the 1980s).

A heavy reciprocating assembly will allow for relaxed driving whereas a lightened assembly may require more attentiveness. For this consideration the lightened flywheel is on the wrong side of the clutch. Same goes for poor traction conditions (wet pavement, dirt roads, etc). In those situations you want to be able to crawl away from a stop at as low an rpm as possible without the engine trying to stall, to control wheel spin.

I like the Yella Terra steel flywheel. Its a bit lighter than the factory unit, but a helluva lot sturdier. The factory flywheel is iron. The Boss 351 had a nodular iron flywheel. The Yella Terra is steel. Get the drift? Steel doesn't work harden & crack like aluminum. Durability is important for street cars, sports cars, road racing, etc. If I were to lighten the drive train, it would be via lighter rear wheels, they seem to provide the most bang for the buck ... refer to my "very important" comment above. They are larger in diameter than any other rotating part of the power train, and there's two of them. They are also on the "good" side of the flywheel for crawling away from a stop in bad weather.