TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Front vibration when accelerating - accelerometer graphs....

Discussion in 'Model S: Driving Dynamics' started by sorka, Jun 21, 2016.

  1. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    They fixed the noise but I've had this vibration between 35 and 50 MPH during full force acceleration that is only getting worse.

    Tesla said they can't feel it when test driving it.

    The vibration is lateral from side to side with a little bit in the forward direction. But because it's mostly lateral, something is disturbing the acceleration force on just one side.

    Frequency is 28 HZ. Total lateral g-force acceleration is 0.8 gs. It's a pretty strong vibration.

    Here are some charts. The blue bulge in each is the vibration.

    Screen Shot 2016-06-21 at 2.45.05 PM.png Screen Shot 2016-06-21 at 2.44.55 PM.png Screen Shot 2016-06-21 at 2.42.19 PM.png

    I used the app called Accelerometer Meter in the Google Play store. Anyone care to download it and take a run from 0 to 50 MPH. If you send me the file, I'll produce the graph for comparison.
     
  2. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
  3. rns-e

    rns-e Member

    Joined:
    May 5, 2013
    Messages:
    384
    Location:
    Denmark
    I also have vibration in the front when accelerating full power, have not been by Tesla yet, but have informed them. Have had it for 1.5 months now. I also have a lot of vibration when braking hard from high speed. I do not think it is the brake discs, as there is no vibration when braking more gentle. Further more i have a clicking sound from the front when turning at very low speeds. It somehow sounds like there is play somewhere in the suspension.

    Other than that, it feels great :)
     
  4. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    Can someone who doesn't think the have the vibration with a PD car download:

    Accelerometer Meter - Android Apps on Google Play

    to their android and grab a few 0-60 runs? It could even be 10 to 60 or a soft start 0-60. No need to slam it. It just needs to be full acceleration within a second or so.

    I held my android on the center console sliders facing up with the top of the phone facing forward.

    I'd like to get some data from a car that doesn't have this issue so I can forward it to Tesla and show them it's not normal.
     
  5. randall_s

    randall_s Member

    Joined:
    Apr 12, 2016
    Messages:
    51
    Location:
    Meridian, MS
    sorka, I recorded one accel run. Here is the raw data:

    Accelerometer Data 2016-06-22 16-07-26

    Rolling from a start of 10-15 mph to full accel in sport mode. Climbing about 5 degree incline. Fidgeting with phone to before and after to start and stop it. Hope this is useful for you.
     
  6. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    Awesome! Thank you. I'll post the graph shortly.
     
  7. StaticDischarge

    Joined:
    Mar 25, 2015
    Messages:
    38
    Location:
    Edmonds, WA
    Screen shot of similar data, 1yo 85D, going straight, hit about 45mph briefly, assuming red is side to side...

    upload_2016-6-22_15-38-2.png
     
  8. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    Can't make sense of it's The Y axis is pulling at least 1/2 g when it looks like it's not really accelerating. The X axis should be circling 0 plus or minus but it's almost always positive. Were you taking a hard corner?

    The app should look like this if you're sitting still. X and Y at 0 and Z at 1.0 g. If you hold the phone facing up flat down on the center console armrests with the top edge of the phone pointing forwards to the front of the car, you should produce data where Y goes from 0 to some positive number. It should max out around 1.1 (Insane or Ludicrous). Ludicrous will max out longer.

    The app should look like this sitting still facing up:

    [​IMG]
     
  9. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    Yes. Cool. That looks just like mine. Do you feel a vibration for about 1 second from second 3 to 4(because yours is an 85D).
     
  10. StaticDischarge

    Joined:
    Mar 25, 2015
    Messages:
    38
    Location:
    Edmonds, WA
    Yes, the latter part of the acceleration has a shudder I've been noticing lately; not sure either way if it has always done it or a new thing.
     
  11. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    Mine started a few months ago. I wonder if it's just really common. I'm going to have to do runs with an IMU attached to each Hub and see if it's primarily on one wheel which I suspect it is given the lateral acceleration.


    So I just realized my lateral acceleration shimmy is pulling twice as many gs as yours. Your total g diff is about .35 while mine is 0.9.
     
  12. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    I'm going to attach an older smartphone directly to the hubs tomorrow and do runs one each to see if one axle is worse than the other.
     
  13. StaticDischarge

    Joined:
    Mar 25, 2015
    Messages:
    38
    Location:
    Edmonds, WA
    I did a few more runs with substantially the same result. Below is an example with two periods of acceleration, one low, the other high. There is some increase in x axis noise with lower acceleration, but there is also an increase in z axis noise. Unclear if I hit a critical speed (if there is one). The high acceleration shows the x axis noise (and shudder feeling); z axis stays noisy but does increase, perhaps not quite in sync with the x, hard to tell. High acceleration period was short as I was running out of road, too many cars. I plan a run on the freeway to see if full power will induce the shudder at a higher speed. I was typically going about the same speed on previous tests. Perhaps it will repeat at higher speed, perhaps not.

    Looking forward to the axle results.

    upload_2016-6-25_8-55-8.png
     
  14. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    I wonder if all of them do this at say the total .4 g spread that your seeing and I'm only noticing because it's worse at .9 gs?

    Anyone else care to try. It shouldn't take more than a few minutes of time.
     
  15. hiroshiy

    hiroshiy Active Member

    Joined:
    Apr 6, 2013
    Messages:
    1,536
    Location:
    Tokyo, Japan
    Hi, @sorka, I tested but my car is 2014 P85 RWD and under full acceleration the rear tires had some wheel spins and my Android phone went from LCD screen up position to LCD down position, in the cup holder, so you see some Z axis movements too. I can retry if you tell me how not to let the phone move there.
     

    Attached Files:

  16. StaticDischarge

    Joined:
    Mar 25, 2015
    Messages:
    38
    Location:
    Edmonds, WA
    I did a higher speed run - started at 50 mph, applied full power until I was going about 74 mph. I didn't feel a shudder. Graph suggests the vibration didn't occur. So perhaps it only occurs under full power in a lower speed range, as suggested previously.

    2016-07-06 21.05.20.png
     
    • Like x 2
  17. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    Just a quick update. A few weeks ago the same Tech who looked at this the first time drove it and confirmed the shudder so I'm secheduled for 8/11 for them to take another stab at it.
     
  18. hiroshiy

    hiroshiy Active Member

    Joined:
    Apr 6, 2013
    Messages:
    1,536
    Location:
    Tokyo, Japan
    Was my test useful? If not I can try again.
     
  19. HyperMiler

    HyperMiler Member

    Joined:
    May 25, 2014
    Messages:
    112
    Location:
    Germany
    Any possibility this is wheel spin cut short by traction control?
     
  20. sorka

    sorka Active Member

    Joined:
    Feb 28, 2015
    Messages:
    3,242
    Location:
    Merced, CA
    No chance. Long after peak torque. In fact torque is half of peak by the time the vibration starts. Also there is no cut in power like there is when traction control engages. Lastly it feels nothing like wheel spin.
     

Share This Page