The overall torsional peak was cut by almost 5 fold over a lightweight underdrive pulley. from 0.22 degrees to o.05 degrees. A quarter of a degree of torsional vibration is a lot and can cause spark scatter and internal mechanical inefficiency.
A Fluidampr works by having its mass tuned inertia ring free-floating in a housing filled with viscous silicone fluid. In a conventional damper, the inertia ring is bonded to the damper hub using rubber that limits movement. In a Fluidampr, the free-floating ring can damp out vibrations over a much wider range. Also the high the amplitude of the torsional vibration, the more the floating ring works to damp it out. This makes it amplitude sensitive. Viscous silicone maintains viscosity tolerance across a wide temperature range. Approximately -40° F to 300° F. This provides very consistent and predictable damping properties. The mass of the internal ring and the viscous damping of the fluid work together to attenuate vibrations. For these reasons, a Fluidampr works better than conventional harmonic dampers.
The Fluidamper has a laser-welded hollow housing that bolts to the crankshaft containing the inertia ring floating in the viscous silicone fluid. All Fluidampr’s are SFI certified to be explosion resistant at high rpm.
On the FA20 engine, the Fluidampr is pretty compact and light. With big V8’s for instance they are much bigger and heavier.
8 comments
Is it worth putting one of these on a 4g63 from an evo 8/9?
We have one on ours!
I have had one on my Evo IX for a year now.
These are one of those upgrades that’s actually beneficial to your car. I installed a Fluidampr on my 2013 FR-S and it really smoothed out the revs overall and gave the engine a smoother feel. Definitely worth doing.
Did it actually get rid of the 6500rpm vibration that the driver felt? The plots don’t look like there’s a huge amount of torsional vibration at 6500rpm, certainly not a peak.
I wonder if it could be supercharger mounting stiffness. Look at how much structure there is on anything front end accessory drive related from the factory. A water pump or alternator has a relatively huge amount of webbing/structure in the block to stop it from vibrating. 2EO at 6500rpm is 216Hz, trying to give something heavy a higher than 216Hz natural frequency is tricky, and a heavy supercharger is likely to need a HUGE amount of mounting stiffness to get above that. By way of comparison, even OEM cast aluminium inline 4 manifolds can struggle to get a high enough natural frequency even though they’re only supporting themselves and a relatively light throttle body. Obviously this flat 4 one is helped by the fact it isn’t cantilevered, but it’s still a lot of stiffness that is required.
Yes you can see it on the plot!
Do these style dampers deal well with the quick changes in RPM? For instance when you go in with two feet for a panic stop or a rev-matched down shift?
That’s a very good question, we have used these for years in very high power drift motors that see a huge rpm variation very quickly and they work well.