[ted]

If by aluminum damper you mean a solid hub, then I'm not an advocate of these as in reality, they are not really a harmonic damper by design. After doing dyno tests on two different Fe's in regards to damper design, the aluminum hub without any dampening capability costs up to 18HP on the typical 500-600 horse engine. Fluid damper designs also did not fare as well as the elastometer design as they ended up costing up to 6HP on average. The base line damper on both engines was the old heavy factory 427 elastomer style damper with the pulley already made on its front. The other interesting fact to come out of the testing was that there is a correlation between damper weight and compression ratio. The higher the static compression ratio, then the more average horsepower that's achieved by using dampers that are correspondingly heavier. Best bang for the buck are the factory dampers but because they are not SFI approved for specific class racing, then I fall back to the Fisher (mechanical friction style) or ATI (dual elastometer). In a pinch, I would opt for using any SFI approved single elastometer design that balances out very close to zero. I'd also consider some of the other mechanical friction designs that are currently on the market as I've run those with satisfactory results.

At this point, I'm not a fluid damper fan and this bears out by the number of crankshaft failures I see where these dampers are being used along with rpm stutter boxes both at the drag strip starting line or as rpm control mid-track. The state of balance of the fluid dampers as received in an out of the box condition also leaves some room for improvement. Although I was initially informed by the engineers that this was a result of the dampers not being warmed up, this has been since disproved.

Just my two cents worth but should be food for thought.