[Goingnowherefast]

I'll give this a shot. I'm a project engineer with ~2 years in Powertrain NVH. If I don't answer anything directly, feel free to ask individual questions. But here's my general breakdown of the data, and some questions mentioned.

Disclaimer:

I have a couple minor issues with the way the data was acquired. Firstly, optical tachos are seldom used in the industry for torsional vibrations. This is because Encoder/CDM's are by far the most precise in terms of pulses per rotation. Optical tachos are used because they are cheap, and easy to use but they have quite bad precision - because of this, take their results with a grain of salt. Additionally, torsional vibrations are highest at low engine speeds. To tell the whole story, I would have liked them to start the speed sweep at 1,500 rpm instead of 2,500 rpm.


1. In general, the FA20 has fairly low 2nd order (and it's harmonics I.E 4th, 6th) torsional vibration content compared to most 4 stroke, 4 cylinder engines. Normally, most modern 2.0L inline 4 cylinder engines seem to be around ~2 degree peak to peak at 2,500 rpm (that's 1 degree peak). So, in that sense, the FA20 has an advantage over traditional inline 4 cylinder engines.

2. It's impossible to know exactly what will harm "X" component unless you do extensive durability/NVH testing on each component - something that a company like Fluidampr will never do. However, in general, it's safe to say that high frequency content tends to be more detrimental to longevity since the energy content is higher - but this is a generalization, not the law.

3. Based on the order plots, I would conclude that the OEM elastomer damper is well tuned to attenuate 2nd order content at high engine speeds. However, I wish they would release the data of order content vs. frequency spectrum, which would give us a wider picture of what's really going on. The viscous damper seems to do a much better job at damping 2nd, and 3rd order content at low-middle engine speeds.

My thoughts:

While I have a few issues with how the data was acquired and presented, I understand it's a small aftermarket company and releasing data like this in any capacity speaks volumes. To me, the OEM elastomer damper is well tuned to attenuate 2nd order (and it's harmonics) content. This coupled with the very low peak torsional content that the FA20 radiates tells me that there's certainly no reason to believe going to a Fluidampr would give you any noticeable positive impact on longterm durability of components (especially oil pump) on a stock rotating assembly.

However, as mentioned, the main advantage of viscous dampers is their ability to damp a very broad frequency spectrum. Changing to a lightweight flywheel, or changing the rotating assembly is where a Fluidampr would benefit. Simply changing to a lightweight flywheel will have a massive impact on crankshaft torsionals on it's own. This is where the broadband frequency damping of the Fluidampr would show it's own. I would definitely recommend a Fluidampr when you have either modified the rotating assembly, or have changed to a lightweight flywheel.

As far as power goes, I think those results speak for themselves. The reduced effective rotating mass certainly frees up a tiny bit of power. I'd also like to add that the lightweight crank pulley that they tested did quite poorly. I'd really recommend not using a traditional lightweight pulley on the FA20.

Feel free to ask any questions you have!