Aluminum Flywheel

[91lxf22a1]

I just bought a Fidanza 8lb aluminum flywheel. Anyone know how much more power will get to the wheels vs the 20-something pound steel flywheel that was on there?

[C91BLX7]

Same power.

[91lxf22a1]

Are you sure? Wouldn't it make sense that less rotating mass=more power to the wheels?

[C91BLX7]

Are you sure? Wouldn't it make sense that less rotating mass=more power to the wheels?

Nope.

[Leung]

it just allows you to rev faster.

[91lxf22a1]

Maybe you guys misunderstood me....It takes power to turn the flywheel, trans gears, axles etc...if you lighten any of those components it takes less power from the engine. So the F22A1 has 125hp stock, a chassis dyno will show MAYBE 85-95 Wheel HP (i dont know exact numbers) so thats what 30-40hp taken away to turn all that? So in theory if the any of those parts are lightened wouldn't the 30-40hp be reduced to 25-35 (example) giving more to the wheels???? so like 5-10hp increase? If i am wrong explain what takes up the 30-40hp from the crank to the wheels.

[Grin0048]

Maybe you guys misunderstood me....It takes power to turn the flywheel, trans gears, axles etc...if you lighten any of those components it takes less power from the engine. So the F22A1 has 125hp stock, a chassis dyno will show MAYBE 85-95 Wheel HP (i dont know exact numbers) so thats what 30-40hp taken away to turn all that? So in theory if the any of those parts are lightened wouldn't the 30-40hp be reduced to 25-35 (example) giving more to the wheels???? so like 5-10hp increase? If i am wrong explain what takes up the 30-40hp from the crank to the wheels.

Lots of moving parts and linkages = lots of friction.

[91lxf22a1]

So you are saying friction is the only reason you lose 30-40hp to the wheels from the crank?? That doesnt seem right.

[Grin0048]

So you are saying friction is the only reason you lose 30-40hp to the wheels from the crank?? That doesnt seem right.

I wasn't suggesting it's the only factor. Obviously, it does take energy to rotate a mass, so it is a factor in power transfer...the important question though, is how important a factor is it? I think what the previous replies are telling you is "not very."

[wed3k]

you will gain a slight amount of power however you loose momentum so it takes more energy to keep the crank rotating.

it's kind of confusing.

[johnl]

Whether or not any power is 'gained' at the wheels depends on how the power is measured.

If the chassis dyno infers wheel power from the rate at which a large heavy mass is rotated (by the car wheels) from X rpm to Y rpm (i.e. an 'inertial' dynomometer), then removing rotating mass from the car's driveline will result in the dyno's load mass being sped up faster, and thus the dyno will 'measure' a higher power output at the wheels.

Inertial dynos don't / can't measure power at a steady engine / wheel rpm, but other kinds of 'brake' dynomometers can and do. With this type of dyno the measured power at a fixed engine / wheel rpm will be no different with mass removed from the driveline (or added for that matter).

The real world affect is that if it takes X kw to maintain Y maximum speed (overcome drag etc), then removing mass from the drivetrain won't affect this at all, the max speed will remain the same (as does the power output).

However, removing rotational mass from anywhere in the drivetrain will reduce the time it takes to achieve X maximum speed (and all speed benchmarks along the way). It's not that the engine produces more power, but that parasitic losses due to rotational inertia are lessened.