Reply to "Flywheel Mass vs. Acceleration"

quote:

Originally posted by JFB #05177:
my $0.02, as a machine dynamics problem and not as an experanced automotive expert.

the benifits of less flyweight mass is the reduction in inertia so power can be applied to acceleration. the 20# less at the motor is where the least amount of excessive weight (inertia) has the most effect. the increase for acceleration in increased by the gear rations so the 20# reduction would be like a #200 reduction at the drive wheels (in 1st gear)

the negative with a light flywheel is in the transfer of engine power into kinetic energy and its storage. a light flywheel will require a very experanice driver to be able to release the clutch and apply throttle to transfer the little KE of the crank/pistons, where a heavy flywheel will deliver the stored KE as the cluth is released.

so if the car was manufactured with a light flywheel, the car would not be drivable to the public and clutches would become a warrenty nightmare as over throttle slipping would be required

the ability for the rpms to spin up quicker would also apply when the cluth is disengaged and they would fall off, thus requiring experance with the throttle to match rpms

This is an EXCELLENT reply & covers the many various facets of an aluminum flywheel.

Especially the experience necessary to properly utilize/drive an engine equipped with an aluminum flywheel. I believe that "Twitchy" is an accurate descriptive term.

Since aluminum flywheels are normally associated with performance engine/s ie; HIGH lift camshafts, which require a certain amount of rpms/throttle to initially gain inertia, it comes a rather nuanced/difficult dance between launching the vehicle( Not stalling) & NOT burning up the clutch.

I purchased an aluminum flywheel in my never ending quest for the lightest reciprocating mass in my new engine build.

I believe I will quickly learn, MUCH to my consternation, that I don't like it!

Also I'm believing, being further educated more in the destructive nature of "Torsional Vibration", thus the purpose/application of LARGE vibration dampers such as those found on the highly coveted BOSS 302 & 351 engines.

For these reasons my "Lightened rotating mass" focus has shifted to just the engine's internals plus the harmonic damper rather than the weigh savings of the usage of an aluminum flywheel.

I might even consider building my engine using titanium wrist pins.

You want to be shocked/surprised...weigh your stock wrist pin...Mark