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Dual Motors Out of Sync?

Discussion in 'Model S: Driving Dynamics' started by OBX John, Jul 7, 2017.

  1. OBX John

    OBX John Autonomous Driving Enthusiast

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    I'm trying to figure out what's bugging me about our new 100D, and I think it's that the motors are slightly out of sync.

    I trade back and forth between driving it and our Model S 75, and the acceleration seems smoother in the 75, and the regen as well. It's like there's a slight lag between the motors on the 100D, and it feels like turbos kicking in on a ICE vehicle when you accelerate hard - two stages of acceleration rather than just one. It's not huge, but it's noticeable.

    I was wondering if anyone else had noticed the same? I'm going to call service, but thought it might be worth seeing if anyone else has had an issue with dual motor timing.

    Thanks for any feedback!
     
  2. RichardD

    RichardD Supporting Member

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    I have a 85D and had a 85+ as a loaner, I have not noticed this. It must be frustrating for you, I would definitely talk with service and take them for a ride and show them what you mean. Maybe one of your motors is "weak".
     
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  3. boaterva

    boaterva Supporting Member

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    With the whole 'one motor is optimized for highway, one for local' paradigm, I wonder if something could be off with how they switchover or however that works. Or perhaps they are fighting each other... I would think if it's not perfect, it would definitely feel 'wrong'.
     
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  4. eye.surgeon

    eye.surgeon Member

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    I hope they resolve the issue for you. I still greatly prefer RWD here in sunny California and hope they never stop offering RWD as an option at all trim levels and battery sizes.
     
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  5. OBX John

    OBX John Autonomous Driving Enthusiast

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    I talked to service they said they would take a look at the logs, and they also suggested changing the performance option to match the 75 which I'll try next time I'm in the car. Should be interesting to see if it behaves the same then.
     
  6. OBX John

    OBX John Autonomous Driving Enthusiast

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    Yeah it's interesting after spending another $30,000 to get all the options... and I end up liking the cheaper car better!

    I hope they never get rid of the RWD too. I'd love a more powerful one.
     
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  7. RichardD

    RichardD Supporting Member

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    I loved driving my loaner, but really appreciated dual motors on sharp turns. Hope they resolve this for you, and please update us on what they find!
     
  8. gavine

    gavine Petrol Head turned EV Enthusiast

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    Try toggling between range mode on and off and see if there's a difference between the modes. I'm pretty sure range mode affects the way the motors behave together in certain situations (torque sleep?). It might help narrow-down the issue.
     
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  9. DIL

    DIL Supporting Member

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    ^^This.
    And now the lightest MS is RWD 75 and in 4 second territory.
    Time for Tesla to start offering performance enhancements to non P cars. Let's have adaptive dampers and equivalent of LSD.
     
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  10. chillaban

    chillaban Active Member

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    Are your tire options similar on the two? Could be traction control holding back throttle to prevent wheelslip.
     
  11. brianman

    brianman Burrito Founder

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    I don't want LSD anywhere near my car.
     
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  12. S4WRXTTCS

    S4WRXTTCS Active Member

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    Weird.

    I have a 70D, and for the most part it feels completely smooth. During hard acceleration it's not as smooth as I want, but the tech said it was perfectly normal. That was over a year ago.

    From my butt dyno there doesn't seem to two stages.

    I will say that I dislike range mode. It makes it way too front wheel drive biased. So I leave that off unless I'm on a trip.
     
  13. whitex

    whitex Active Member

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    Let us know whether switching the perf mode worked for you. 100D does have more power than pre-July'17 75D, and the power is limited from stand-still to keep up traction. We have a similar situation (both MS are white too :)) and I've never noticed that, though I foot-limit the 0-10 acceleration on the P85D as I don't feel like retrieving the cubby content from the back seat all the time. ;)
     
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  14. OBX John

    OBX John Autonomous Driving Enthusiast

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    I'm still not sure what's going on, but the motors seem fine now under hard acceleration. There's still a "two stage" feel at lesser levels, but that could just be an issue with the accelerator system. I'm also pretty sensitive to my cars, so it could just be my expectations are beyond the reality.

    I had more weirdness yesterday when AP and TAC went out on both my cars, seemingly at the same point geographically. I took my kid to a swim party in the 100D - on the way back had to take over from AP when it missed a curve, and it never came back on. Drove the 75 to pick him up, and same thing happened, AP and TAC went away - wasn't using it, but near the same area. Auto lights came on despite bright sunlight, and stayed on the whole way home. Tried a reset, didn't do anything, but now everything is fine this morning.

    I called service, they called back and said they did see some "weird" error codes, and would look into it.

    Just a reminder that we are driving bleeding edge tech I guess!
     
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  15. scottm

    scottm Active Member

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    In the old world I would suspect a "dead spot" on the accelerator pedal position sensor on a drive-by-wire car.. some place where the linearity is distorted. It could also mean your go pedal is not firmly bolted to the firewall and is slipping under certain pressure... very few degrees movement have very big implications on power output.

    Model S is drive by wire too.. so maybe try to narrow this down.. are you feeling the "turbo lag" at a certain pedal position, regardless of actual speed? I know this is harder to do without "gears" allowing you to separate motor speed from road speed.. But from standstills and various rolling speeds you'd get a chance at pushing through a good range of the pedal travel that might have a "dead spot" in it.

    if someone is telling you they're seeing something weird in the logs, ask them to elevate your case to the next level of engineering diagnosis
     
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  16. OBX John

    OBX John Autonomous Driving Enthusiast

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    Yes, about midway down it seems like there's a surge of power after a slight delay. It's not consistent anymore, so I'm wondering, is there a break in period? The noise from the front motor has changed slightly I think, less raspy and more of the high pitched whine I'm used to in the 75.

    The dynamics seem to change a bit as the car warms up too. I'm still trying to figure it out, but it seems like the car is smoother than it was a few days ago. Next road trip I'm going to spend a lot of time playing with it - right now the traffic and tourists here are so heavy that I don't have many chances to test it.
     

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