[CobraEd]

It seems that for around town use the aluminum flywheel would always be better. At any speed, if you floor it, your revs will come up faster and the car will accelerate faster because there is less inertia to overcome. So if you are cruising along next to a guy with a new Viper on the highway at say 55 mph and you floor it, you will accelerate faster with the aluminum unit because there is less inertia to "spin up".

A heavy steel flywheel is better for drag racing only (not any racing, only drag racing) because you spin up the engine IN ADVANCE OF THE RACE while still at the line to say 5,000 rpm. Now you have this heavy flywheel spinning at 5k, you dump the clutch and all that inertia works with the engine torque to help keep the revs from dropping for a good launch. Then when you hit 2nd and third (4th??) the spinning inertia again helps keep the revs up for more forward thrust at each full throttle shift. So this is good for a drag race.

On the street, you dont dump the clutch at 5 grand everywhere you go and speed shift at max rpm every single time you shift. You want the ability to spool up fast from any speed/rpm including low rpm cruise for fast acceleration from any speed/rpm.

Ed