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You upgraded from 85 to 85D; what difference in watt hours per mile?

Discussion in 'Model S: Driving Dynamics' started by brucet999, Aug 28, 2015.

  1. brucet999

    brucet999 Active Member

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    I'm deciding between RWD and AWD for a car in SoCal where snow country driving would be a rare event.

    It would help me to know what differences real world drivers have noticed when upgrading from 85 to 85D, especially as to wh/mile. What, if any, advantage would I get for an extra $5k?
     
  2. Stoneymonster

    Stoneymonster Active Member

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    The performance difference is quite noticeable. My lifetime Wh/mile is a few % better so far. I expect this to improve as weather changes and I take longer highway drives.
     
  3. Khatsalano

    Khatsalano Member

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  4. brucet999

    brucet999 Active Member

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    Thanks. Can you explain why you wrote, "You can definitely feel a strong pulling-through-the-corner sensation in the 85D. I’ve been told this is less so in the P85D and the 70D and that makes sense because of the difference in forward/rear power balance"? I would have thought that 85D and 70D would be more similar than P85D and 70D.

    Regarding torque steer in D models, I assume it would be less noticeable than in a FWD car?
     
  5. RobAndrews510

    RobAndrews510 Member

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    When we were looking into buying, I was told it has equal length half-shafts, so it shouldn't have any. So far, I haven't felt ANY torque steer in my 85D. (I've had a couple FWD cars that had unbelievable torque steer...)
     
  6. Khatsalano

    Khatsalano Member

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    Bruce, I am not an engineer, but I am an avid driver. It seems to me that in AWD cars, those with a balanced front/rear power distribution have more torque steer than those with a weaker front/stronger rear distribution. Is torque steer more noticeable in an AWD or a FWD car? I think it really depends on all kinds of variables like weight distribution, dimensions of the vehicle, rolling momentum, tires/shafts/bunnies/ponies and things I can't explain in sufficient detail. I would just encourage you to try out the cars in question and see if you can feel it. If not, just disregard torque steer as one of your deciding parameters!

    Rob, I drove my 85D for probably 17,000 miles and swore I had no torque steer ... until I drove the P85+. It was a world of difference. The human mind has the ability to adjust to things at a very subtle level without full awareness that we are doing it. I noticed that in the P85+, I was making minor corrections with my hands on the steering wheel as I accelerated ... but there was no need for such corrections. I was just used to it from muscle memory on the 85D.

    - K
     
  7. AWDtsla

    AWDtsla Active Member

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    You don't get torque steer in symmetrical AWD systems. This usually occurs from unbalanced half-shafts in a transverse engine layout.
     
  8. Stoneymonster

    Stoneymonster Active Member

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    Wouldn't you still get small amounts from tractions differences (tire inflation differences, wear) and smaller imperfections?
     
  9. AWDtsla

    AWDtsla Active Member

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    You should have neither, but I've never been able to detect any pull from a under-inflated tire. I would notice. Why would this effect be more than it would be on the rear wheels? If you have one under-inflated tire you will slowly drift towards that side at highway speeds.
     

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