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Innovative Polyurethane Engine Mount Vibration Test: K-Series Engine

It would be an understatement to say that the increase in vibration and noise that comes from changing to polyurethane engine mounts in a TSX is "noticeable." But the benefits of these mounts are a strong attractor to installing them. The mounts last longer and allow considerably less engine movement, providing a better power transmission from the crank to the wheels.

How much vibration is there, though?

And is it too much for you? The answer is really very subjective. So we decided it was best to try and show in as scientific a fashion as possible just how much vibration increase you'll get.

First, we needed a tool to measure vibration. Look no further than the smartphone in your pocket for something like this. We downloaded this simple app from the Google Play store. With this app, we can measure and record a datalog of the vibration profile with and without the mounts installed and graph them to show the difference.

Since the vibration is felt on the interior and the dash transmits the brunt of it, we decided to place the phone there for the test.

With the car warmed up (to make sure we were in low idle) and the accessories turned off, we idled and then revved the engine to show where the vibration is felt most. Here is what we came up with when transposing the graphs:

The green line is the vibration profile with the stock mounts. The orange is with the Innovative mounts with 75A bushings.

The difference is obvious. But to explain a bit more of what you are looking at, read on.

  • This graph is measuring vibration as a logarithmic function, like a seismograph. That means 4 is not 4 times as big as 1. It is 1000 times bigger.
  • The flatter areas of the graph, from 0 to about 49 are where the car is just idling. Notice that the orange line is rougher but not a lot rougher. The amount of vibration coming into the car is noticeable in the chassis. You can feel it in the seat and the floor, but it is not very dramatic. The graph does not show interior sound volume at idle, which is a little higher as well.
  • Where you really notice the vibration increase is when you blip the throttle. Stock, the throttle inputs are barely perceptible, and the line actually gets smoother as you rev the engine.
  • The polyurethane mounts transmit a really abrupt stumble that shakes the dash hard enough that it actually rattles the phone around a bit. That means, the orange line's spikes are a bit exaggerated in the graph in the negative direction, as the phone bounces off the dash slightly. But, they are representative of what your initial reaction will be to mounts. It is startling at first.
  • After you rev, there is a period of time from about 109 to 124 on the graph where it takes a while for the vibration to settle down. After that it normalizes and you can't really tell they are in there aside from a little extra harshness and sound at idle.

Unfortunately, as much as I tried I could not get a realistic graph of what happens when the car is driving with my crude setup.

Aside from a similar noise and vibration profile as you notice at idle, it is largely an invisible mod while driving, although you will have better throttle response as less power is soaked up by the mounts.

Ultimately, the very worst part of this mod is from this stumble with revs off idle.

The engine always does it, but it is so apparent. It feels like the dash shakes so much, but then only for a moment then it smooths out. It is true the mounts do soften a bit over time but even a year and a half after installing them they feel pretty much the same. We tried softer 60A mounts and found there to be little or no perceptible difference.

All this results in our advice for those considering polyurethane engine mounts for their car:

  • Don't buy them because they are more durable than stock mounts. If your stock mounts are broken, and you are not looking for anything other than to fix them, just get new stock ones.
  • However, if you are looking for a performance upgrade, and/or your mounts have broken repeatedly because they are not up to the punishment you are giving them, polyurethane mounts are great with a moderate compromise in luxury feel.
  • At times the increased vibration is a turn off, but ultimately you will get used to it over time.
  • The durometer is not very different with respect to comfort level. middle range durometers will be good as they are durable yet still have a degree of dampening.

About the Author

Marcus di Sabella Marcus is the founder of Heeltoe Automotive. He's been working with cars (mostly Honda cars) since 1996, and has been providing enthusiasts with excellent products, services, and web experiences since 2002. He's been published in Honda Tuning, and holds a degree in Engineering Technology.

6 Comments


 
Wes
03-01-2014 01:55 PM at 1:55 PM
What I ment to say was that hard data such as this was very interesting because it was not purely subjective! Whoops sorry Marcus!
 
Wes
02-28-2014 01:31 PM at 1:31 PM
Very interested to see some hard data (less subjective) on these. Would definitely love to see Hond-R mount review! I have the Ingalls ETD myself and found it to be a nice compromise. Extra power to the wheels, but less harshness compared to polyurethane mounts I had in my integra. On the negative side the ETD probably wouldn't help get as much power to the wheels as the PU mounts. To each their own.
 
Ryan Digman
02-22-2014 04:42 PM at 4:42 PM
Very good write-up Marcus. This is valuable information for those looking into polyurethane mounts as an upgrade. though most don't understand the research behind it. I've seen guys throw 85a mounts in a fairly stock mildly upgrading vehicle , than complain about the vibration. I will be upgrading to the 75a myself on my 04 UA6 with a built 3.5 swap that will be turbocharged. always great stuff coming from Heel Toe!!
 
Casey Vaught
02-22-2014 03:44 PM at 3:44 PM
How do the Hond-R mounts compare to the stock TSX with respect to durability, power loss and vibration; where would you place them in comparison to the lowest stiffness innovative set?
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MrHeeltoe: We can only speculate on this one at the moment. Being rubber, we expect the Hond-R mounts to be slightly more comfortable. But there is still not nearly as much compliance in them as the stock mounts. We'll need to put a test on those on our to-do list!
 
USDMHART
02-22-2014 03:02 PM at 3:02 PM
I'm so excited and happy for the contrast you guys brought to the fore-front of the Innovative mounts after searching for ages and stumbling upon these mounts I'm definitely getting them for my CM5. Thx a lot and keep up the fantastic job!
 
Danny
02-22-2014 02:16 PM at 2:16 PM
Good informative write up!

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