"Stop the presses

So I went online to locate the ATI graph/chart that I thought I just recently viewed in the newest ATI product catalog I got in the mail. The online graph does not jive with what I shared here regrading the comparison of ATI vs FD in rpms.

I will get a copy of ATI's catalog at PRI Thursday and I might have to retract my incorrect comment. Sorry"

So the attached pic is from the latest "ATI 2020 Winter catalog".

As AndyF has already noted there are many variables in tuning a damper. I suspect there are at least 12? known elected variables that they account for in the final design. I'd bet there are another dozen variables felt too difficult to measure or insignificant enough to design in, and I also suspect there is an infinite of unknown undiscovered other variables also at play. All to mean, pic your poison.

So I also suspect ATI being a for profit corporation, picked a specific ATI damper to best promote their marketing strategy. I'd give them the benefit of doubt and believe they did not pick competitor test example s that would test poorly.

That being said, all three dampers in the graph appear to test the same up to approx 5800 rpms, at the point their effectiveness separate, then the FD tests best, until approx 6900 rpm where its non effectiveness quickly climbs, and the ATI becomes more effective as the rpms climb. I would not draw a solid conclusion from this, but I believe its indicative in general as to the best rpms effective range a user could be guided by. Such as if you never seldom operate your engine above say 7000 rpm, the choice is rather clear. None of the above numbers are etched in stone, especially if one refers back to my opening comment on variables and tuning dampers.