Here is some old post I have found about aluminum flywheels:
Right from Centerforce themselves.
Originally Posted by Will Baty
Another thing to think about is that in most cases the steel flyhweel has more heat sink. This typically means longer clutch life, seeing how heat is a big killer for clutches. The steel flywheel has more mass which allows it to absorb and dissipate the heat that is generated from the clutch when the car is put into motion. Both flywheels do have pros & cons, you should look at what some of the other guys with similar or the same set-up as what you have are using. Another thing to look at is what percentage of your driving is around town daily driving? Do you want every ounce of performance out of your car or are will to sacrifice a little performance for more drivable clutch around town? I not saying that the Aluminum flywheel is bad by any means I know allot of guys with the Aluminum flywheel that have no problems what so ever. I am just saying that steel vs aluminum on the street 9 times out of 10 the steel will have the better clutch feel.
Just my 2 cents.
Will Baty
Centerforce Clutches
This is posted from FastDriver - The answer to your question is that a 15 lbs weight would be easier to catch/stop if it has been thrown at you at the same speed as a 40 lb weight. A pretty obvious answer, but I think you are misinterpretting the results. A drag racing launch has nothing to do with ease of launch. If it did, you wouldn't launch at 6500 rpm, you'd launch right off of idle. Also, my clutch doesn't seem to have any problems grabbing my flywheel at any rpm. My tranny doesn't seem to have any problem managing the shock, and with the right tires and suspension, I will launch this car right off of redline with a single clutch drop.
The point is that you want as much stored energy to jump into your tires as possible, and you want your suspension/weight distribution/ tire combination set up so that it can handle all of the power and effectively put it to the ground - as opposed to wasting it by blowing away the tires.
In regard to your posit about stored energy being meaningless, I'll counter that stored evergy has everything to do with the difference between a heavy flywheel and a light one. In fact, stored energy is the only cause of a performance difference between an aluminum and iron flywheel.
The aluminum flywheel does not store as much energy as rpms increase which gives it an advantage in that the energy that would be stored in the flywheel has instead been exerted into the rotational force in the drivetrain and hence the driving force/power of your car.
In drag racing, that extra stored energy in the flywheel at a stop is put into your tires as soon as the clutch is dropped causing more force/power driving your car as it leaves the line. As your car moves down the track and rpms increase, the energy is transferred back and forth from the flywheel to the tires as rpms increase and then decrease (as you shift). Finally, when you cross the traps, rpms at the top of their powerband, the stored energy in the flywheel did not get put to good use. So, the advantage after you leave the line is to the lighter aluminum flywheel. Does it make up for the Iron one? Possibly. The longer the track, the more likely. However, will the difference be significant enough to justify the extra expenditure? Not to me."
"we lost like .20 on our 60 foot times with an alum flywheel. its the initial shock the torque ripping the tires is what was different and in turn they say about every .10 in the 60 foot is about .15 tenths in the quarter. i find this to be a close fact went from 11.50-11.55 to 11.68-11.71 in the quarter i dont remember mph."
I beleive it was Eagle on here (the one that sells the rotating assemblies - Brian?) that said the AFW does react differently under normal conditions. He seems like a pretty credible source on it as well seeing how he does sell the rotating assemblies Ed Curtis and some others (can't remember) where suggesting keeping a steel flywheel in the heavier side of the cars (like 3200lbs and up)...so that is where my lx falls into.
For autocross cars, I agree...your up in the revs for 99% of the time (almost literally) and your not building up speed (revs) if your autocrossing right so the AFW would be beneficial in that case.
For the picky daily driver like me...I'm not for the AFW.
In the end, it is up to you and what you are willing to put up with, a steel unit or an aluminum, your choice
