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 and becoming a Supporting Member. For more info: Support TMC

Model 3 Ludicrous 2.0 seconds flat?!!

Discussion in 'Model 3' started by Chopr147, Feb 12, 2017.

  1. garsh

    garsh Re Member

    Joined:
    Apr 2, 2016
    Messages:
    332
    Location:
    Pittsburgh
    You're thinking about how drag race times (usually quarter-mile times) are reported. A 10-second car completes the quarter mile anywhere between 10.00-10.99 seconds.

    I've never heard anybody use that same phrasing when talking about 0-60 times. But who knows. Maybe the source said "in the twos", and it got misreported as "two". Furthermore, it's just a report of a rumor from a source of unknown credibility. We'll see what comes of it.
     
  2. Model 3

    Model 3 Active Member

    Joined:
    Jul 13, 2014
    Messages:
    1,910
    Location:
    Norway
    Maybe. But on the other hand I have seen people posting about the early Model S P85(+) that was marketed as a 4 seconds (4.1 if I remember correct?) car, but was tested to be a 3 seconds (3.9 if I remember correct?) by Motor Trend i think it was. And I also think I saw someone posting about Model S become a "2 seconds car" as soon as it got under 3 seconds. But this posters could of course done the same misunderstanding as I did?
     
  3. Chopr147

    Chopr147 Active Member

    Joined:
    Apr 3, 2016
    Messages:
    1,575
    Location:
    Wantagh, NY
    0-60 in 2 seconds means just that. NOT 2.1 or 2.2 or 2.3 or 2.4 or you get the drift. He may not have used the word "flat" but that's what it means. 2.99999 is a lifetime more in 0-60 times.
     
    • Disagree x 1
  4. strider

    strider Active Member

    Joined:
    Oct 20, 2010
    Messages:
    3,129
    Location:
    NE Oklahoma
    Well, I am about to step over the line in my knowledge of electric motors. @JRP3 or others feel free to jump in. But as I understand it one of the problems with the current pack is voltage sag under heavy load. If you increase the voltage you decrease the amperage for the same amount of power. This should translate into less voltage sag and less resistance due to hot wires.

    So I believe that going to a higher voltage pack and other pack architecture changes (the change to 2170 cells - is the C rate higher than the 18650's?) could allow a similar amount of power out of the 3PDL pack as the SPDL pack. I still don't know if this will make the 3PDL a 2-second car but I'm eager to see what madness the Tesla team cooks up next.
     
  5. Model 3

    Model 3 Active Member

    Joined:
    Jul 13, 2014
    Messages:
    1,910
    Location:
    Norway
    May very well be, but then, why in this thread when they discuses the same news, why does it seems like almost everyone is treating it as "less then 3 seconds"?

    Example:
     
  6. JRP3

    JRP3 Hyperactive Member

    Joined:
    Aug 20, 2007
    Messages:
    11,615
    Location:
    Central New York
    Torque is generated by current. At low RPM's the inverter is taking power from the pack at high voltage and low current and converting that to high current and low voltage. Voltage to the motor increases with speed and as long as voltage is higher than the base speed rating of the motor current can be sustained. Since I don't think Tesla's motors run faster than base speed during a 0-60 run I don't think a pack voltage increase would have any effect on 0-60 times.
     
  7. Trev Page

    Trev Page Member

    Joined:
    Sep 21, 2012
    Messages:
    603
    Location:
    Aurora, Ontario, Canada
    I want to chime in and make it clear that the source is indeed closer to Tesla than most of us but made it clear that the performance seen was not destined for Model 3. We were both in agreement that the drive train being tested is the "maximum plaid" for a new Roadster
     
  8. Mad Hungarian

    Mad Hungarian Member

    Joined:
    Sep 25, 2015
    Messages:
    279
    Location:
    Montreal, QC, Canada
    Trev, you're harshing my buzz. I was all ready to pull the trigger on a military surplus G-suit :D.
    Kidding aside, I wasn't realistically expecting the max 3 setup to hit 2-ish seconds. Conversly though I don't buy that Tesla would limit it to protect the S's honour. As has been pointed out around here many times there are many examples from other premium brands where the smallest performance variants are very close - and occasionally quicker - when compared to the big guns. Witness Audi's diminutive TT-RS, whose 0-60 in 3.6 is within a blink of their flagship S8 Plus' 3.3 seconds but costs about half as much. So even though I don't think the hottest 3 will eclipse the S anytime soon, I won't be surprised if it can at least come somewhat close.
     
    • Like x 1
  9. wdolson

    wdolson Supporting Member

    Joined:
    Jul 24, 2015
    Messages:
    3,721
    Location:
    Clark Co, WA
    Ultimately it boils down to how much instantaneous power the pack can put out. Because of the inverter, the actual voltage and current out of the pack is only an issue for I^2R losses between the pack and the inverter (which is a short run anyway). The P100DL gets better performance than the P85DL and P90DL because the 100 KWh pack is capable of higher instantaneous power. The Model 3 is not going to have the instantaneous power output capability of the 100 KWh pack and wishing otherwise isn't going to change that.

    I agree that the test performance they got from a Model 3 mule is probably experimenting for the next gen Roadster which might be built on a modified Model 3 platform. Tesla might make the next Roadster with a larger battery and less cargo and passenger space. Putting a 100 KWh pack into a Model 3 platform with Model S P motors would probably be enough to goose launch times down into the near 2s range. The pack would have to be laid out differently, but without a backseat a Model 3 could have extra modules behind the front seats. Because the Model 3 platform is narrower than the Model S, it may not be possible to get the Model S large motor between the wheels, but the Model S small motor would probably fit.

    At the moment this is probably just a proof of concept experiment and is not slated for production any time soon.
     
    • Like x 1
  10. Chopr147

    Chopr147 Active Member

    Joined:
    Apr 3, 2016
    Messages:
    1,575
    Location:
    Wantagh, NY
    Well, gee thanks Trev for bringing some common sense into the conversation. I already have a couple racing bets on the horizon , started saving for the Model 3 130kw and looked into a military surplus G-suit like the Mad Hungarian (Al Hrobosky?)
    Dream killer!
     
  11. McHoffa

    McHoffa Member

    Joined:
    Sep 29, 2015
    Messages:
    735
    Location:
    Canton, NC
    I seriously doubt the Model 3 will hit 2 seconds, but it's very likely the next roadster, built on the gen 3 platform, will. I've been saying for a long time that I think they will try very hard to hit 1.9 seconds in the Roadster. If they can say "under 2 seconds" in a production car, they can sell that thing for $200k and it would sell like hotcakes.
     
  12. EXOTIC1

    EXOTIC1 Member

    Joined:
    Jan 23, 2014
    Messages:
    329
    Location:
    MANY PLACES
    At 200k i don't think it sells in any type of high volume. The ferrari and lambo crowd won't change from their brand and a 200k toy for even hardcore TESLA owners isn't feasible for most. I think you'll see the roadster start with a 100k msrp and top out at 170 range. For 100k starting point many potential buyers will line up for a sports car doing under 3 sec.
     
  13. McHoffa

    McHoffa Member

    Joined:
    Sep 29, 2015
    Messages:
    735
    Location:
    Canton, NC
    I don't know... a Model S P100D maxes out at $167k, and we've seen plenty of those around.
     
  14. strider

    strider Active Member

    Joined:
    Oct 20, 2010
    Messages:
    3,129
    Location:
    NE Oklahoma
    Wouldn't the C rate of the cells matter? If the 2170 can discharge at a higher rate (without damage) than the 18650's then it should be able to generate a similar amount of power even though the pack is smaller. AFAIK we haven't seen any data on the C rate for the gigafactory 2170's but maybe I missed it.

    Yes the P100DL has higher performance than the 85 and 90 because they all use the same cells so they're up against the same C rate limit. Once there you have to add cells to get more power.

    I'm not being obtuse, I'm actually trying to learn something at this point :)

    Gah, you all are harshing my mellow and now I'm wavering on my Model 3 reservation - may keep driving my Roadster v2.5 until Roadster v4 comes along....
     
    • Like x 1
  15. JRP3

    JRP3 Hyperactive Member

    Joined:
    Aug 20, 2007
    Messages:
    11,615
    Location:
    Central New York
    Sure, but we have no evidence to suggest the 2170's will have a higher C rate, and usually a physically larger cell of the same chemistry has a lower C rate, (though I don't think the differences between the 2170 and 18650 aren't large enough to make a significant difference.)

    The lighter Model 3 will of course need less torque, and current, to accelerate.
     
  16. wdolson

    wdolson Supporting Member

    Joined:
    Jul 24, 2015
    Messages:
    3,721
    Location:
    Clark Co, WA
    Even if the C rate is higher, it has to make up for the smaller pack size. To get the same C rate out of an 80 KWh pack as a 100 KWh pack, the C rate needs to increase 25% (1/0.80 *100 = 125%). There are some Li-ion chemistries that allow very high discharge rates, but they have other draw backs. Tesla uses the NCA chemistry, which has the highest energy density of any chemistry. They are probably up around 300 Wh/Kg now (the theoretical limit). NCA cells are limited to 1C discharge.

    NMC is also used for EVs and Hybrids and can be formulated to do 2C discharge rates, but the best energy density is around 220 Wh/Kg, most cells. The source below doesn't indicate what trade offs are necessary for the higher C, but I wouldn't be surprised if those cells have lower densities (150 Wh/Kg). With battery tech, there are always heavy trade offs.

    LFP can ger very high C rates, but have only 1/3 the density of NCA. One of the best chemistries for high C is LTO chemistry, but it tops out at 80 Wh/Kg. It's good for stationary storage where you can have large battery arrays, but would be a poor choice for a car.

    Ultimately what is going to sell cars is the best possible range. The car enthusiasts pay attention to the top end performance, but the bulk of buyers are going to be perfectly happy with the performance of the standard model. The performance of a Model S original 60 KWh pack is better than 95% of cars on the road. When comparing the acceleration of the old 60 to other sedans, it's much better than most. The 0-60 of the old S was around 5.5s. A Toyota Avalon is around 6.5s, most Camrys are around 8s, most Ford Fusions are in the 6.5s range, many of the BMW 3 Series are over 6s, etc.

    The biggest limitations EVs have is range and price. The price issue is narrowing faster than the range issue. Most buyers of EVs are going to be concerned about the range rather than performance of the most expensive version because performance of whatever they buy (if the car was designed right) is going to blow away anything in the same market niche for performance.

    Tesla is going to optimize the 2170s to get the best possible range rather than a higher C rate. If someone stumbles upon a new chemistry which meets all needs (safety, life time, etc.) and happens to have a higher C rate, Tesla won't hesitate to standardize on it, but right now improving range and cost are mission #1 and #2 for battery chemistry. Tesla's engineers will work magic to get the highest performance version to be as much of a super car as possible, but they aren't going to get a special battery for that use if it means compromising in any other area.

    A link describing the main li-ion chemistries in use today:
    Types of Lithium-ion Batteries – Battery University
     
    • Like x 1
  17. JRP3

    JRP3 Hyperactive Member

    Joined:
    Aug 20, 2007
    Messages:
    11,615
    Location:
    Central New York
    #57 JRP3, Feb 17, 2017
    Last edited: Feb 17, 2017
    BU is ok for some general battery knowledge but they aren't great on specifics and are usually a bit out of date. Obviously Tesla gets significantly more than 1C discharge from their NCA packs for example, and they also charge higher than 1C at superchargers. BU's specific energy number for LTO is also low, I think Toshiba SCIB LTO is over 100Wh/kg now.
    Regarding C rate for a specific chemistry, there are ways to increase it without chemistry changes, though you usually sacrifice energy density. You can use a higher number of thinner layers instead of a lower number of thicker layers to improve C rates for example.
     
  18. wdolson

    wdolson Supporting Member

    Joined:
    Jul 24, 2015
    Messages:
    3,721
    Location:
    Clark Co, WA
    Yes, Battery University isn't great for the latest information, but it is a good resource for the basic concepts.
     
  19. Mad Hungarian

    Mad Hungarian Member

    Joined:
    Sep 25, 2015
    Messages:
    279
    Location:
    Montreal, QC, Canada
    LOL! You know, until just a few years ago I had no idea Hrobosky was the original M.H.
    My boss took to calling me that long ago and I always assumed it was a reference to the crazed Lapchik character (seen in my avatar)from The Gumball Rally, a 70's car cult film that we both love. My penchant for riding fast motorcycles in freezing temps may also have had something to do with it :D
     
    • Like x 2
  20. Chopr147

    Chopr147 Active Member

    Joined:
    Apr 3, 2016
    Messages:
    1,575
    Location:
    Wantagh, NY
    I remember Hrobosky from the Royal/Yankees rivalry of the late 70's. Reggie was not too happy about his ball slamming into the glove act and nearly caused a brawl. :)
    As far as bikes go , the coldest I rode in was 18 degrees. My face and fingers fell off :)
     
    • Like x 1

Share This Page