dgeesaman

iTrader: (10)

Your handling will improve, for sure, but they flywheel effect of the 16" rims may actually reduce acceleration. For autocross, I guess that's not too critical, but wheel weight alone doesn't guarantee better acceleration. It's how far from the axle the wheel mass is distributed that gets you accelerating faster - and 15" combos tend to have lower flywheel than 16" or 17".

Which makes me chuckle when someone puts 17s or 18s on and a y-pipe when the first get the car and marvel at how much 'faster' it feels. hahaha

Dave

d00df00d

iTrader: (4)

Neither of those would help your ride, handling, or braking.

I'm not sure if performance axles are any lighter than stock. Even if they are, though, they probably wouldn't make very much of a difference because all the mass is in the center of their rotation.

A flywheel would certainly help your acceleration somewhat. In terms of acceleration in first gear, every pound you remove from the flywheel is worth about 10 pounds of dead weight on your car. It will also make the engine rev quicker, improve throttle response, and take some stress off the clutch and other transmission bits.

dgeesaman

iTrader: (10)

Remember, this is a very rough rule. Although d00df00d probably knows this, comparing flywheels by weight is the same as wheel combinations - it neglects the flywheel effect (rotational inertia). Different 9 lb flywheels have different rotational inertia depending on how they are constructed. Stock flywheels tend to be very rim heavy from driveability, and aftermarket flywheels are not only lighter, but more hub-heavy. So losing 4lb going from a stock flywheel to performance flywheel is greater than losing another 4lb going to an even lighter performance flywheel. (I'm making up numbers with 4lb, but the point is the same). I'll bet that rule is based on going from a stock setup to an aftermarket setup.

Unfortunately, I'm not aware of any easy way to measure the rotational inertia of a flywheel or wheel/tire combo. You'd either have to calculate it, or do testing to figure which one is best. It would be very cool if someone had (or made) such a tool and tested stuff.

Dave

d00df00d

iTrader: (4)

That's a good point.

Aren't some stock parts near the outside of the flywheel also transferred over to the new flywheel in most cases? For example, I understand that the Unorthodox Racing flywheel, which claims to be the lightest, is only the hub, and that all the other bits have to be reused from the stock flywheel.