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Fascinating and intriguing power/performance figures on the TM website

Discussion in 'Model S' started by mgboyes, Apr 9, 2015.

  1. mgboyes

    mgboyes Member

    Apr 16, 2014
    United Kingdom
    #1 mgboyes, Apr 9, 2015
    Last edited: Apr 9, 2015
    So many questions coming out of this chart that's now up on the TM UK website ( - note that the US version is different), such as

    • why are they holding the 70D and 85D back so much?
    • with 422hp how come the 85D is slower to 60 than my P85 which only claimed to have 416hp (it would be fascinating to see the torque curves on these smaller motors but even so given the traction advantage of AWD I'd expect the 85D to be faster than it is)?
    • why doesn't the P85D have the same 257hp front motor as the other D cars?
    • and most notable by its absence... what is the overall hp figure for the P85D?


    At least this explains why all the early press coverage talked about the 70D having 514hp
  2. mhpr262

    mhpr262 Member

    Sep 19, 2012
    Old Europe
    I suspect it does have the same motor, but a cheaper, less powerful (or restricted) inverter - similar to how the only difference between the normal 85 and the P85 was a more powerful inverter.

    Maybe that is what the possible 2.8 seconds to 60mph rumours are about? Once they are sure the battery can handle it, perhaps the front motor controller restriction will be lifted and the P85D will put out 727hp total.
  3. fadkar

    fadkar Member

    Feb 18, 2015
    Orange County, California
    Very interesting questions... I wonder why they idn't advertise the overall HP for the P85D even though they did for every other model...
  4. Splunge

    Splunge Member

    Apr 12, 2013
    Considering the recent higher horsepower numbers for the P85D on the Swiss ordering page, I think it is a given that more horsepower will be released soon, possibly for all models.
    P85D swiss.jpg
  5. Kbsilver

    Kbsilver Member

    Jul 25, 2014
    Central NJ
    I would say this is more marketing than technical limitations. If the 70D has a lower voltage battery pack than the 85, it will reduce the max power available. If you do not get more with a more expensive model, no one would ever buy them.

    At this point anything in the 5 second 0-60 range is more than enough for me. Other than maybe a handful of times in a decade, other than bragging rights to your friends, do you really NEED anymore? Don't get me wrong, for the right price I'll take the faster car.
  6. mspohr

    mspohr Active Member

    Jul 27, 2014
    I don't understand the difference between the "hp" and "hp motor power" numbers.
    For instance, the 85D has "422 hp" and "514 hp motor power"? What does this mean?
  7. thelastdeadmouse

    Apr 11, 2012
    Potsdam, New York
    My thinking goes like this. For the 70D, the total power available from the inverter at any given time is 329 hp. Each motor is capable of putting out much more than half of that though, so that any given time the car can put up to 257 hp in any single motor depending on available grip and efficiency.
  8. Moparposterchild

    Oct 27, 2013
    Los Angeles
    My thinking is all the cars are limited primarily by software and not so much the components. This would simplify the production and minimize the amount of unique parts for manufacturing. I think they use the software to limit the HP on each car, but if unlocked the motors could all be capable of the same performance... I do believe the rear motors are probably unique from the front motors, but in theory I think the front motor on the 70D & 85D could put out as much power as the front motor on the P85D if unlocked, and the same would apply to the rear motors as well.
  9. Bearman

    Bearman Member

    Nov 17, 2011

    Motor Hp = The maximum amount of power the motors can output, unsure if this number is for short bursts, constant output or something in between.

    Hp = The maximum amount of power the battery and inverter can output, may also be software limited.

    Lowest number is what to go by.
  10. Danal


    Dec 11, 2014
    Fairview, TX, United States
    You have a good point. It is very, very difficult to pick a single number for an electric motor. The real limit is how much heat you can carry away. At, we are flying a motor that weights only 1900g (4.1 Lbs), and is the size of a fat beer can at 15kW (20HP), continuous, on our "electric motor glider" project. We are doing that by pumping tremendous amounts of air through the motor itself. Take away that cooling, run at the 15kW power level, and our motor would last seconds.

    In Tesla's case, with liquid cooling, the whole motor and cooling system could be rated for a continuous power. But continuous is not a great marketing number. Those numbers on the web site? No clue what they mean, and Tesla won't answer. The one fact we know: The web site numbers DO NOT line up with the "Certificate of Origin" on delivered cars (738 SAE HP for P85D CoO), nor with any kind of calculation based on a Dyno or track run (measured with accurate equipment).

    - - - Updated - - -

    In this picture here we can see a good picture of how we work extra hard to cool the motor. Using all of the air that is captured in the cockpit area and venting it directly over and through the motor assembly. One observation on the construction of the motor is that it is not ideally designed for maximum cooling from airflow flowing through the motor.
  11. brucet999

    brucet999 Active Member

    Mar 12, 2015
    Huntington Beach, CA
    I think this may be another term for "peak horsepower", which you may sometimes see claimed on things like shop vacs and other power tools. 5 hp on a 120V machine is impossible in continuous operation (1hp = 746W so 5hp = 3730W and that would require 32 amps; way beyond the wire capacity of any 120V circuit.), but momentarily, as the motor starts, it can draw a lot more power and that is why your 120V shop vac can claim 5hp.

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