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Does control arm bushing composition affect ride quality or NVH?

Fargo

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The stock passenger side UCA bracket was somewhat bent, and the sides had collapsed .2 inch inward. When it came time to attempt removing the original bushing, I could see the bracket wasn't suitable for a simple press-in option.

Enlarging the holes in the UCA yoke to 12mm was not a problem. I did it anyway to use the JJs. Synergy also offers a forged replacement yoke with 12mm bolt-holes as an alternative to drilling.

Adjusting pinion angle reached a point where adjustable LCAs were needed for the rear. I installed Synergy arms.
View attachment 77069
Thanks for the info. Did the bracket bend when using the stock arms and bushings? Sounds like the Currie upgrade might be good insurance.

I'll have to look into that Synergy bracket too. I have concerns that it might not be the right length since it was designed for a JK. I do like how the Currie gets welded to the bracket and not the axle.
 

astjp2

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Ok, here is some scientific research on vehicle NHV...for those who want to read it. I am now looking for a vibration analyzer that can be mounted on the suspension...which would eliminate the butt feeling. Tim
 

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Fargo

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I am now looking for a vibration analyzer that can be mounted on the suspension...which would eliminate the butt feeling. Tim
Could you find a secure way to mount a (old) smart phone to an arm and just run an app like this:

Mounting could be as simple as a couple of hose clamps tighted around the phone. Not perfect, but if the differences are large they would show up. Then just drive around the block a couple times and take the average. Provided you can find an app that stores enough info.
 

Fargo

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If you have two sensors, another option would be to run 2 different arms at the same time. Then mount one sensor in the middle of each arm. Obviously pot holes hit by only one wheel would be different, but general road aggregate would be more or less similar and would give an idea about control arm isolation.
 

astjp2

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I was thinking that the axle side would be my baseline and the frame side would be the amount reduced, if the bushings isolate the vehicle from the road nhv... you could test tires, control arm bushings, the road itself, mount it the same way for shocks to see its isolation...this is just a mental exercise for me. If I could come up with something like a wilcoxin 991v sensor that I could bolt to each end, attach wires to and then monitor on an tablet, it would be real neat to do comparisions of different products. Tim
 

fuse

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Could you find a secure way to mount a (old) smart phone to an arm and just run an app like this:
Mounting could be as simple as a couple of hose clamps tighted around the phone. Not perfect, but if the differences are large they would show up. Then just drive around the block a couple times and take the average. Provided you can find an app that stores enough info.
Collecting accelerometer data in Android almost trivial -- I could write that code. Analyzing it is not as simple as just averaging the raw data. At a minimum, you need a spectral analysis, and you may need a filter to remove some noise levels. You may also need to do some normalization to compensate for gross changes in orientation and velocity.

So you could get the raw data from an old phone. But do you have an environment for a controlled experiment with different control arms? And would you know how to process the data?

These aren't rhetorical questions. I know enough to know the problem isn't simple, but not enough to solve it. Maybe someone else here does.
 

astjp2

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I was thinking of something more basic, a comparative of 2 different sensors, so if the axle side has an IPS of 4.9@ 1100 hz, and the frame side is 3.6, then there is a reduction with such and such bushing...

If you want to compare tires, use the axle side, calculate the RPM at a given speed, and measure the lug spacing, that will give you the frequency, analyzer will give you the IPS, anything under .9 is not really felt by a person, 1-1.5 is minor feeling...there is a chart that I use for dynamic balancing airplane propellers, I would have to find it. You would mount the sensors vertical to calculate the load transfered from the axle to the body for one data set, another would be parallel to the arm...
 

astjp2

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Collecting accelerometer data in Android almost trivial -- I could write that code. Analyzing it is not as simple as just averaging the raw data. At a minimum, you need a spectral analysis, and you may need a filter to remove some noise levels. You may also need to do some normalization to compensate for gross changes in orientation and velocity.

So you could get the raw data from an old phone. But do you have an environment for a controlled experiment with different control arms? And would you know how to process the data?

These aren't rhetorical questions. I know enough to know the problem isn't simple, but not enough to solve it. Maybe someone else here does.
You know this might be as simple as sitting on your phone, that would be a true "by the seat of your pants" evaluation.
 

Fargo

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You know this might be as simple as sitting on your phone, that would be a true "by the seat of your pants" evaluation.
I wonder if that would work. Wouldn't your body be acting as a shock absorber though?
You might be able to just set it on the dash or something. That would tell you if the road NVH is more than the drivetrain NVH as you drive. Part of what makes this difficult is that much of what we feel comes directly through the steering wheel. But now you got me curious. I might try to find a good app and just try that in different vehicles. If there is no difference between my Pathfinder and my Jeep I'll know the test is faulty, because I can certainly feel a differnance driving them.
 
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Fargo

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I would do it right away, but have some other weekend plans that I can't change. But I'm going to look into this. I already downloaded a couple apps to try.

Do a search in the Play store for NVH. There is a $300 app that uses vibration charateristics to troubleshoot problems in different cars. Quite an interesting approach to vehicle diagnostics. Yet its what good mechanics have done for years to to listen and feel for problems. Not sure I would spend $300 on it when I can plug into and OBDII a lot cheaper. But it would still be a good tool to have if it was a little cheaper.
 

astjp2

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I just downloaded the vibsensor 2.0.0 app from Now Instruments and Software. just holding it in my hand and shaking the phone showed data. I would need to be able to email it to compare data, but it is an interesting idea.
 

astjp2

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I don't know that it needs to be sat upon but certainly in close proximity to the driver's seat. I'd probably bungee it to the bezel around the steering column.
Realistically I was thinking literally in my back pocket. I would not mount it to anything but the seat, because that is where the driver feels it. I dont think we are looking at pedal vibs or steering wheel ossisilations, so I just need to go for a drive and see what the data says. I dont know if I can post it here or if I need some type program to get it to print as a pdf. This is just something to play with. Tim
 

Sundowner

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Realistically I was thinking literally in my back pocket. I would not mount it to anything but the seat, because that is where the driver feels it. I dont think we are looking at pedal vibs or steering wheel ossisilations, so I just need to go for a drive and see what the data says. I dont know if I can post it here or if I need some type program to get it to print as a pdf. This is just something to play with. Tim
Build a solid mount that attaches to the front of the seat riser; you'll still have possibility of moving around in the seat and causing vibrations, but it will at least be minimized.
 

Fargo

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I downloaded the same app and went for a drive with it sitting on my dash. When I started the drive I had snow packed in my wheels so I had a bad vibration. This was the first time I've been excited about snow packed in my wheels. But it gave me a way to test the app. So I went for a drive. Recorded the result. Cleaned the wheels and went for another drive. The difference was easily recorded. Showing a difference of 2 in each direction when packed with snow and reduced to 1 after I cleaned the wheels. This app might just work.
 
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