Can someone give the low down on the pros and cons of these two in comparison? I see that ati makes them out of both materials. Im sure the aluminum will help with performance to a degree but has to come with negatives or they would all be aluminum no?

Years ago I tested a all aluminum BHJ balancer on a NHRA class leagl 340 stocker motor versus the stock balancer,13 lbs versus 7 lbs, no stinking changes on torque or horespower none at all measured Looking back now we should have done that test at the track, not on a engine dyno As far as which one is better at absorbing crankshaft shocks I bet the heavier one is better, maybe not I have both types of ATI dampeners on my motors, I can't tell the differences between them. The motors are not twins so not a decent comparision at all

From everything I've read/heard, I would agree with Cab that the heavier one will absorb vibrations/harmonics better than the lighter one. Solid aluminum hubs with are said to contribute to broken cranks and other problems due to no dampening properties. An ideal set-up would be an aluminum center with a steel outer ring which would provide the best of both worlds - lighter weight for faster reving with a heavier outer ring to dampen the vibrations and harmonics. But since the benefits would be minimal with an aluminum center, I simply use a quality steel/steel balancer for durability. (Weight reduction closer to the center of rotation provides less benefit than weight removed further out from the center.)

The heavier damper will help your crank last longer.

R.

Thnks guys... Thats what I needed to know.