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Should we be concerned about the 85D?

Discussion in 'Model S: Ordering, Production, Delivery' started by saz25, Oct 12, 2014.

  1. saz25

    saz25 Member

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    Hi,
    Usually when I buy a new car, I don't buy the first year of a new model. I wait a year or so to allow the manufacturer to get the bugs out, so to speak.

    I am about to order an MS. As much as I'd like the 85D, should we/I be concerned that its Tesla's first attempt at a dual motor design? I understand from reading this forum as well as Tesla's forum, that many customers had issues with motors in the "early" years. I assume (and I am comfortable) these are resolved or I wouldn't be at the point of almost ordering.

    But the dual motor and all its complexities of when and how to transfer torque to/from each wheel, regen braking, etc, could be problematic when it first ships in Feb '15. If I was to order today, I would probably get one of the early units, maybe in March. They have had 3 years to iron out the issues with the existing motor. Now we will have 2 new/different motors on the D.

    Its for those reasons I am leaning toward the 2-wheel drive. Does anyone else share this concern?

    Thanks.
     
  2. uselesslogin

    uselesslogin Enthusiast

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    The motors are a new design so you might have some concern there. But as far as torque transfer, regen braking, etc. that is all software. So if there are issues with that kind of thing it will get fixed in a software update. That being said the problems with the current motors were generally vibrations that could be fixed with a $.50 shim or a zip tie. The only reason Tesla swapped so many drive units out is that was the fastest way to get people back on the road.

    Maybe that would help, but I'll also mention there is some confusion as to the range and some people think the 85D actually gets 30 miles more range than the 85. That is not true. The 85 gets 285 miles @65 mph and the 85D gets 10 miles more. Maybe that will help your decision. The EPA numbers on the website are not comparable.
     
  3. gene

    gene Active Member

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    Me, I like simplicity. That's why if I was ordering new, I'd get the the 2wd version. Plus, I really like the frunk for cargo and spare tire space on long trips.
     
  4. lolachampcar

    lolachampcar Active Member

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    I'd be a little more concerned about those brakes if I were you (and I am). Unlike the Brembos used to date, these are new fancy bits from Bosch. As Elon is fond of saying, it normally takes a few (three is his favorite) iterations to get a technology matured.
     
  5. Kandiru

    Kandiru Member

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    Great OP. Indeed, many cars need smoothed out, often times has to do with defective parts from suppliers, like the infamous water pump in B8 Audis.

    That is why ordering my S85P may have to wait until summer, when more information from beta-testers accumulates.
     
  6. JST

    JST Active Member

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    Is anyone else using this tech? I haven't seen a full description of exactly what they are doing, though it sounds similar to what Mercedes used on its E class for a while (and then abandoned, iirc).
     
  7. lolachampcar

    lolachampcar Active Member

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    #7 lolachampcar, Nov 1, 2014
    Last edited: Nov 2, 2014
    The Porsche 918 I believe is the only other car using them so, not too many on the road :) There is a thread going on TMC about the new brakes with images of the master and calipers.

    Thanks JST
     
  8. JST

    JST Active Member

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  9. Saghost

    Saghost Active Member

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    As you'll see in the other thread cited above, the new system in unique to Tesla so far, with direct electric motor force on the master cylinder piston.

    The Volt, the Porsche 918, and the Mercedes system you mentioned all use a hydraulic pump and high pressure fluid reservoir to give them boost.

    In principle it should be like electric power steering, which is generally better than the older hydraulic forms - more sensitive, more flexible, and quicker to respond.

    The folks with Autopilot sensors all have those brakes, and the couple reports I've seen have been positive, though it is very early days so far.
    Walter
     
  10. JST

    JST Active Member

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    Though, in general, electric power steering assist systems have been criticized for not offering the same level of feel and feedback as hydraulic units.

    That criticism may not be directly translatable to electric brake boosters, though.

    Edit: I'd love to hear a review from someone who drives an older car and a newer car back to back.
     
  11. lolachampcar

    lolachampcar Active Member

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    I'll stop by the service center and ask to drive one of the new ones. If they are only being delivered to customers, I'll ask the recipients of incoming cars if they would like to swap a test ride.

    I'll also shoot pics of the calipers if not already available from another owner/member.
     
  12. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I'm not particularly concerned about the D because there are three new things (brakes, motor, sensor suite) compared to the original Model S where everything was new. My #5130 car has been as reliable as any other car I've had. More reliable than some.
     
  13. JST

    JST Active Member

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    I think in that other thread someone shot pics of their newly delivered car's calipers. They looked like the same Brembo fixed piston units they've used from the start. Sounds like the iBooster integrates with the rest of the hydraulic system pretty cleanly.

    But it would be good to get confirmation.
     
  14. JST

    JST Active Member

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    Here's the post, #29 in that thread.

    P85D - Electric Mechanical Braking System - Page 3
     

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