I feel like I have to give a plug for an accelerometer / vibration analysis tool which is able to isolate and locate vibrations in a car.
In my recent saga of chasing vibrations, I started researching vibration analysis tools through this Audi Technical Service Bulletin (pdf attached to this post at the bottom), which recommend the use of a
Vetronix MTS 4100 NVH Analyzer by Audi Dealers.
After researching the above tool for a while, I found a 5-part video series created by John Kelly of the "Weber Auto" youtube channel. Apparently Mr. Kelly works in the Transmission Lab @
Weber State University training professional automotive technicians
Anyways, as I dug into this more, I realized that Mr. Kelly has also been writing vibration diagnosis software since 1994. His original diagnosis software was written for MS DOS 6.0. I know
@gsxr can relate to this.
About Us <--- fascinating history!
Then I realized after 2.5 decades of iterating his NVH analysis software from DOS to Windows, his company (NVH Software) finally took advantage of the fact that mobile phones have accelerometers built in, and now they write this NVH app which basically replaces the old clunky Vetronix MTS 4100.
Vibration diagnosis for cars, trucks, SUVs, and commercial trucks using the NVH App. Automotive Technicians can increase their income!
vibratesoftware.com
Anyways I highly recommend this tool. It was only $99 and you can see some sample results here:
The rear ride height does not have any effect on driveshaft alignment on cars such as ours with IRS. …The SLS system adjusts the entire frame/unibody. Or said in another way, it only moves the axles. SLS does change the angle of the axles' CV joints which have both upper and lower ranges...
www.500eboard.co
This tool helps you quantify vibrations and helps you isolate where vibrations are coming from. i.e. - place the phone on the steering wheel, the dash, the rear deck, etc --- this helps you isolate where vibes are coming from.
As well, as the tool counts the frequency of the vibrations, it is able to tell you if the vibes are related to wheels, drivetrain, engine, etc. Lastly, because the tool quantifies everything, you are able to track what the result of any change you make to the car might be. In this manner, I was able to determine that changing differential mount shims and transmission mount shims didn't do anything.
This tool takes the guesswork out of chasing vibrations.