Fluidampr harmonic damper - for race/track only use - Experiences?
 

I know some NA street/HPDE, and FI guys use these, and they are particularly beneficial at the low Frequency/RPM spectrum, and offer broad dampening without a need for a specific tune region, but who out here is racing with one? Or at the track long-term with a Fluidampr?

I bought one and it's been installed from the very first time my car went to a track, but upon a lot more in depth digging, it seems that the Fluidampr is actually worse than the OE damper at controlling high frequency, high RPM vibrations. These are the worse kind to have because they happen more frequently and affect crank driven components like timing and oil pump components, etc. Lower order/frequency vibrations aren't as damaging a they don't happen as often, as can clearly be seen that the OE damper is concerned with controlling those, for long-term health of the motor.

My car only sees the track, so their marketing data regarding the lower frequency, and lower RPM vibrations don't have much meaning to me, as the vast majority my RPM's are 5000-7500.

I'm not interested in the underdriven ATI, so I'm seriously considering re-installing a new OE damper for better long term high RPM dampening.

Even their own data clearly shows the OE controls vibrations better in high frequency, which is why they decided to compare it to the undamped, lightweight pulley for marketing purposes. Not bashing the product, I own one, and think it works, but for a more specific use, like full time track, I'm beginning to think this may not be the best option.

The other part of the equation is the LWFW, that virtually all of run. It's known that using a lighter flywheel can shift some vibrations to a higher frequency, and while it's not a huge concern with our boxer motor, using a "heavier" lightweight flywheel may also be beneficial. I'm actually going to replacing my ACT "streetlite" setup with an Exedy LWFW/Sachs clutch, which is about 1lb heavier, to also help provide more dampening.

Feedback or experiences are welcomed, I can't seem to find many discussions on this topic.

The problem I have with fluidampr is they have never told anyone what type of vibrations will actually damage the car. Is that because they have zero clue and have never tested for it, or because everything they say is total garbage?

I thought the consensus was that the Fluidampr were better for cars that stay in the high RPM range vs. something like a lightweight pulley. I have no personal experience with the Fluidampr

They do, but you have to read their comments closely to see it, and they actually tested it very thoroughly, more thoroughly than any other company out there that I can see. But, while their results show improvements in lower frequency, their summary data does try to avoid the discussion of the high frequency increase over OE. Perhaps they deem the increase isn't enough to worry about, for daily drivers, but for a race car that lives in that region, perhaps it's worth a closer look. I would have to think this product is marketed toward the masses, so that would primarily be targeted toward the street/track enthusiast who mods and drives it in stop-go traffic. So perhaps that's why they deem this product to be a big success over the OE damper, as it does cover a more broad range of vibration, but in the most critical region, it's slightly worse. Is that enough to worry about, I don't know, and that's what I'm trying to figure out.

All vibrations are somewhat bad, but the high frequency ones are typically the worst. The higher the frequency/order, the more times they are felt in each revolution/RPM, which is why they can be destructive.

I wasn't able to see/find this data at the time I bought one, and I reached out to them for input specific to this, but haven't heard back.
I've already ordered a new OE damper and plan to install and test and see if my butt dyno can feel less vibration at high RPM.

High RPM engine failure could be a due to a million and one things, it's going to be nearly impossible to trace it back to the Fluidampr, that is to say if it is the culprit.

Honestly I don't even get why people change their crank pulleys. Unless you're building some 9000rpm high rev/NA screamer, pushing the rotating assembly to its absolute limit, the OEM pulley should suffice.

By no means am I saying the Fluidampr will cause failure, I don't think it will, I'm just wondering if the OE damper is the better long-term solution for a track/race-only car (assuming it is also replaced as needed to ensure optimum performance)......that answer isn't easy to get, but certainly an educated decision can be made if the information can be accurately waded through. I know the fluid dampers have a longer service life, I don't care about that, as I would be fine replacing a $100 damper every few years.

This is where help from Fluidampr would be very nice. If they simply confirmed that the level of high frequency vibration from their damper is still nothing to worry about, compared to OE, and that the bigger benefit is from controlling the ignition/harmonic vibrations in the lower frequencies still applies to a race car, then I could live with it. I'm waiting for an answer from them....lol

Because a lightweight crank pulley is a difference you can actually feel. Just like a lightweight clutch is something that you can actually easily tell the difference.


I agree with you that if there ever is damage it would be almost impossible to tell where it came from. That is my problem with the advertising scheme of fluidampr. They throw up a wall of data without ever stating they have proven any of it has ever caused any actual damage.


If they have tested and found actual damage done to a car because of vibration, they haven't given any proof of that. Meanwhile Subaru states their boxer engines are internally balanced and need no actual harmonic damper.

Lies are the best value adders in most industries. Bring something up as a potential issue and say that you've addressed it. Instant street cred!

Really though, I hate to be a cynic, but I agree with this. Whether smooth is better, or if the harshness does/does not cause issues is the real question. DOES it make things smoother? yes. Is that better for the engine's reliability? Who the hell knows. But it's smoother.

It's like grain-free pet food. Pets have been eating grain filled dry food for ages and generally are just as well off. But GRAIN FREE somehow is suddenly great, and having grain in the food is worse. Because it is worse. is it better for them? Who knows. It doesn't have grains in it so it's "better" somehow because it's different

Is the fluidampr not heavier than the stock pulley?

Perhaps @CSG Mike can chime in on the fluidampr in a race/sustained high rpm environment, afaik he's had it on his car for awhile now.

It is heavier by about 1lb, but it's rotating inertia weight due to the floating internal design makes it 3.8lbs.

I guess the better question is, looking at the data I've provided, is controlling the 3rd order vibration, and the net gain of the Fluidampr in that region, more beneficial than just the slight increase in vibration in the 6th order regions?

It's easy to look at a graph and make assumptions, and in reality these number may all still be very reasonable for long-term engine health. I'm just wondering which one is best recommended for road racing.....ask 3 vendors and you'll get 3 different answers. lol

I just got off the phone with somebody at Fluidampr, they told me the control of the higher peak/amplitude angle vibration in the 3rd order is of more value/importance. Now I can understand that case to be made, as that is the actual angle of vibration on the crank.

With the supposed tight bearing clearances these motors have, I assume control of any large torsional vibration areas may be of the greatest value. But they also conceded that their damper can't do everything for this application and it begins to shed off it's high frequency control a bit more than OEM. I can only assume it's due to weight and the frequency this one is more tuned for. I'm guessing they could probably design one more for high RPM as well, but didn't have that discussion yet.

Good discussion, however they didn't fully answer my questions, they just pointed to the biggest delta in the graph and said it was the best.

I can also see how this damper may be a good choice if you decide to run a lightweight flywheel as well, as it may have the more broad ability to dampen the shift in harmonics it cause over the OE one.

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!

What is a traditional lightweight pulley and what is the opposite? Thanks!

Thank you so much for your input, I'm a ChE so this is out of my wheelhouse. lol. Your thoughts are pretty spot on with Fluidamprs response this morning to my email. They also said that the amplitude of the high frequency vibrations of both OE and Fluidampr are so low, that neither are of concern. So basically then, it's a case of the fluidampr simply damping the dominant 2nd/3rd orders even better. On the race track, you will see ~4500 RPM in slower corners pretty regularly, so the benefit, based on this info seems like a reason to continue using the Fludampr. If you have a street car, or a dual duty car, then it seems like a no-brainer to use one.

I added the fluidampr originally because I installed a lightweight flywheel and it seems my reasoning for the decision was correct. So really the MOST ideal setup would be Fluidampr and OE flywheel. So it's the lightweight flywheels that are ultimately the biggest contributor to bigger vibrations, which we all already knew. I will decide to test either the OE or a slightly heavier Exedy lightweight flywheel (12.8lb), than the current ACT streetlite (11.8lb). In either case, the heavier the better as it will shift frequency lower, and even more into the hands of the fluidampr to control. I would never, ever put an undamped pulley on this car. Note, the test car they used had an OE clutch/flywheel, so it shows how much Fluidampr improves over OE components. This gives me confidence that the Fluidampr may actually be the best choice to use no matter what flywheel is chosen. This was their exact response:

"Thank you for contacting Fluidampr. I apologize for the delayed response. I was out of town on business travel and still catching up on emails. The FA20 is a very solid platform right from the OEM. The testing done in that write up is a stock car with an intake, exhaust, and very mild tune. That was to show a solid base setup. In a 4 cylinder application the 2nd order is the most harmful and destructive. Rule of thumb is half the cylinders will cause the most destruction. On the FA20 the higher orders are irrelevant.

Any time you lighten the mass such as a flywheel or lightweight pulley you are changing the engines harmonics and will see an increase in harmonics. The narrow band tuned elastomer damper for the factory cannot protect the engine efficiently with such modification as a light flywheel. More racers will choose the dual mass flywheel for longevity of a race engine, after they find that light weight is not the best option in a situation like this. A fluidampr is the best option for its broad band ability to tune out and absorb the engines harmful harmonics.

The cart tested used a stock clutch/flywheel. Our Fluidampr is broad enough to work on a vehicle with a lightweight clutch/ flywheel, I would say more than half of people running our damper use a lightweight flywheel. From what we see with our customers is that by switching to a light weight setup creates a problem (vibrations) that didn’t exist. In reality the weight savings and rev up time you would get with those lighter parts are not really that much and what you get with the added vibrations is not a real benefit."

Fluidampr also provided me the full 10 order summary vs. OE. I've attached a pic of it here, let me know your thoughts. It seems that from 4500 - 7500 RPM, the fluidampr purely by measure of RPM sweep, has more RPM below the OE than above it, and is much lower peak to peak (more smooth).

In general, it does look smoother, and probably why these tend to create a bit more power and torque, especially in the mid-range. Mine was no exception, it makes good torque. Regardless of the plot, it seems that a lightweight flywheel would benefit from a Fluidampr.

I asked about the peak at 6K, they replied:

"It is a 2.5 order. With off firing orders, you can see the excitation order move around depending on frequency shift (mainly due to increased hub inertia of the viscous damper over the rubber tuned part.) As long as the overall vibration level is maintained it should not pose any harm to the engine on off firing order conditions."

On full throttle upshifts on straights for example, I miss this because my RPM's are always around 6200-6300, but for other areas, where you sweep through that area, it's not really any worse than how the OE swings up really high at even higher RPM. I can't see a reason to remove it from my car, especially since I want to keep a LWFW for sprint racing purposes. If I was endurance racing, it might be different, but I'm racing it in 15-20 minute sprints, that's it, so the performance trade-off I feel is worth it, as long as the Fluidampr will protect it. Damn, I wish we had some vibration data with a LWFW!!!