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torque: can numbers capture the driving experience?

Discussion in 'Prime Technical Discussion' started by adrianvm, Nov 7, 2018.

  1. adrianvm

    adrianvm New Member

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    After driving my Prime in EV mode a bunch I went back to the Sienna and, at least for low speed driving around town, it feels like driving a slug in comparison People often talk about the Prime having "instant torque" as an explanation for why the car is so responsive at slow speeds. I'm wondering if there are specs that make this characteristic apparent. I looked around and could not find any kind of torque curve that shows a number for the Prime at 0 mph. The official spec says 105 ft-lb for the Prime (with a mysterious @3500) and 269 ft-lb for the Sienna. But these numbers aren't at a standstill, I'm assuming.

    So I'm wondering if there are numbers, or a graph that would make it apparent than the Prime is more responsive. Can this characteristic be captured by specs rather than vague talk of "instant torque"? And what about a comparison of EV to HV on the Prime that would explain why the handling is not as snappy in HV mode?
     
  2. schja01

    schja01 One of very few in Chicagoland

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    There must be an App for that.
    Smartphones have accelerometers.
     
  3. Zythryn

    Zythryn Senior Member

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    Electric motors offer 100% of their torque at 0rpm.
    Internal combustion engines may have an impressive torque at their peak rpm but they can't deliver it at slow speeds typically.

    The torque curve of an electric motor is basically flat, at 100% throughout typical driving speeds around town. Perhaps a couple points below.
    This is one of the reasons the Prime gives such a good around town driving experience :)
     
  4. adrianvm

    adrianvm New Member

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    It sounds like maybe you're answering my question with a "yes" but without the numbers to back it up. I mean, if the Sienna delivers only half its advertised 269 ft-lb torque at 0 rpm that's still more than the advertised 105 ft-lb torque for the Prime. So are there performance curves we can get for the Prime and the Sienna that show this? Are there published values for torque at 0 rpm? My friend has a "performance car" with an ICE. Can I determine if his car is better at low speeds than a Prime even though I can't drive it because it has a manual transmission? He said "My car is famous for having more torque at idle than most engines have at all."
     
  5. Zythryn

    Zythryn Senior Member

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    Very few people graph the torque curve of the Prime. If you google, you may find one, I couldn't with a cursory search.
    In general this is what the EV vs ICE torque curves look like.
    [​IMG]
    If your friend has an ICE, he has 0 Torque at idle.
    You may have better luck comparing 0-20, 0-30 or 0-60 times.
    Unless he has a very exotic ICE, most EVs would just embarrass him off the line.
    In a longer race, he may win, depending upon what he is up against and what he is driving.
     
  6. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    torque: can numbers capture the driving experience?
    Uh.....
    No.
    Only the driving experience can capture the driving experience.
    But numbers are important in an apples-to-apples comparison, which is why brochures are full of things like skid-pad and slalom numbers, 0-60 accelerations, 60-0 braking times, and other performance metrics.
    They are to the automotive industry what player stats are to pro sports.
    They capture some important information, but as everyone knows or should know, there is much more to the overall driving experience than numbers.
    One of my very favorite cars was a 1996 Geo Metro Xfi, which was a complete piece of garbage, automotively speaking, but it was a blast to drive - as was my Miata, which had just about as much brake horsepower and torque as a Prius Prime does now.......but a VERY VERY different driving experience.

    The Prime JUST ISN'T isn't what you would call a 'sporty car.'
    Otherwise the 0-60mph times for the G4 Priuses would not be over 10-seconds.
    When you mash down on the fun pedal in a Prime, you're ONLY throwing all of 121BHP and 151 ft/lb of torque into the power splitter and once all of the energy is divided, transferred, and distributed the car lumbers its way up to speed quite well for what it is, and what it is built for.
    From 0 to about 20mph, a Prius can "feel" rather more spirited than it really is because as mentioned above, electric motors are basically binary devices....but they're not magic.
    After all....one does not expect to yank one of the cheerleaders off of the sidelines, jam him or her into pads and cleats, and score very many touchdowns - even though they are participating in the same sport, on the same field.

    Tesla 3's on the other hand have a much different driving experience because they have adult sized tires, a more efficient drivetrain, and the Tesla brings about 330 more ponies to the party....along with enough torque (470+ Ft/Lbs) to blur one's vision if you're not careful with the throttle.
    VERY different driving experience.....as one should expect from a roughly $55,000 car.
    Actually....to be fair, Teslas punch above their weight in straight-line performance, and on a good road.....but a Prius Prime will beat it in a coast-to-coast race, for now, .....and do so more cheaply....for now.
    The dependability part is pretty much a fanboy argument until statistics assert themselves.
    YMMV......

    FOR now?
    Primes are efficient, cheap, dependable, and available without waiting in line....which is another kind of driving experience.
    Again....
    YMMV.
     
    #6 ETC(SS), Nov 7, 2018
    Last edited: Nov 7, 2018
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  7. Zythryn

    Zythryn Senior Member

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    I love this analogy!
    To the OP, think of trying to get an idea of what it feels to return a kickoff for a winning touchdown, by looking to the stats. It just doesn't work.

    ETC(SS) is quite correct when it comes to high levels of performance. However, if you are talking about day to day around town performance, the Prime can be quite spritely.
    That electric motor counts for a lot :)
     
  8. adrianvm

    adrianvm New Member

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    I don't know anything about sports, so the sports analogy is lost on me. Also in the last 20 years I've basically driven only Siennas and the Prime. I was pondering my friend who, even though he only drives in Seattle area traffic jams, insists that he needs to have a "performance car" and wondering what the point was. But as someone who would rather not drive at all, I do find that I prefer the Prius to the Sienna. So I was wondering if this is similar to my friend's experience with his Cadillac CTS-V. How is it to drive that car around town? I know it's going to blow the prime away going 0-60. Looks like it might do it in under 4s. But is that all that a "performance car" is for when talking about an ICE? As I noted, I can't actually drive my friend's car to directly experience it due to the manual transmission.
     
  9. Zythryn

    Zythryn Senior Member

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    The current CTS-Vs are all automatics. Not sure when GM last sold a manual version, could be a year ago, could have been several.
    The newest runs 0-60 in 3.8s, at a $73k price tag.
    For performance, he would do better with with an electric car.

    However, car purchases have an emotional component for most. I can’t stand the large, blocky styling of Cadillac. Sounds like your friend enjoys it, but it certainly isn’t the performance alone ;)
     
  10. adrianvm

    adrianvm New Member

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    It's a 2009 CTS-V. I know many people definitely have an emotional connection to their cars. I have to assume that "ordinary" electric cars like the Leaf and Volt aren't going to measure up for my friend---he'd need a Tesla. But I was curious to see numbers that could compare the Prime to the CTS-V. He also claims that a car with zero torque at idle would never move.
     
  11. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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  12. Zythryn

    Zythryn Senior Member

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    Thanks for that correction!
    After doing some more research, it appears an ICE needs to produce enough torque at idle to run the alternator and other workloads. The percentage of torque at 0 rpm I would think is minor, but perhaps your friend can tell you.
    In short, any EV produces 100% of its available torque at 0 RPM. That is what an ICE can’t compete with.

    For new versions of each car, the performance Model 3 beats the CTS-V by over 1/2 second. The CTS-V has a much higher top speed.
    And of course, the launch process in the Model 3 is vastly simpler, yet more effective. However, while it is more effective, your friend may have an emotional attachment to the process in a stick shift and so prefer that.
    In addition, the Performance Model 3 is cheaper, starting at $64k vs $72k for a new CTS-V

    The best way to convince your friend is to have him test drive a performance Model 3.

    But again, any EV will be more spiritedly on city streets.
     
  13. Starship16

    Starship16 Senior Member

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    The Prius is slow. Torque and all. Who's kidding who?

    And what kind of idiot wants to drive a Prius fast?!

    Now if you're talking Tesla, those things are rockets. But where (and why) are you going to use, or even need, all that speed? Complete waste of money. And Tesla shouldnt make those vehicles so fast.

    For all the jet jockeys out there, who race their cars from red light to red light, have fun paying $300 a month for gas. Makes no sense to me. Or go blow $100K on a Model S. Both are stupid decisions.

    Who cares about torque. The nuts in America need to slow the hell down!

    Don't analyze it. Just drive it. :LOL:

     
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  14. Zythryn

    Zythryn Senior Member

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    To some, performance is desired. To others it is drive quality/handling.
    EVs, including the Prime, give a wonderful experience in city traffic. If that is what someone is looking for, I see nothing wrong with pointing out the advantages plugin vehicles offer.
     
  15. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Use a time plot from the app to see how quickly the engine hits peak torque. You already know that the electric motor has peak torque from a standstill.

    The time-to-peak is what you are feeling. It's affected by engine design, ECU programming, transmission gearing & shift logic and more.

    A sport bike can rev to 11k RPM in around a third of a second, because it's so small. Very low mass.

    A large diesel truck engine can get there quickly because its peak torque is at low RPM- not much delta required despite high mass.

    A supercar can do it insanely fast, because now they all have a launch mode that raises the idle- you guessed it- closer to that required for peak torque.
     
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  16. adrianvm

    adrianvm New Member

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    Well, that's what I don't know and thought the numbers might reveal. Is it possible that the Prime outperforms my friends CTS-V on city streets at low speeds? My friend said something about liking the idea of fuel economy...but no way could he drive a hybrid car because of the poor performance. It made me wonder. Someone else on this thread said something about having the car idle at high rpm so that the torque is immediately available. Wouldn't that make the ICE handle like an EV? I assume the cost of this would be efficiency.

    I think it depends on what you mean. If you're talking about max speed, or 0-60, then sure. But after driving Siennas for 20 years and then getting in the Prime I had the problem of accidentally going too fast around the neighborhood, so I really can't agree with the claim that the Prime is slow. The way the Prime handles below 30 mph it's much faster and snappier than the Sienna. And my dad's old Outback makes the Sienna look like a jackrabbit.
     
  17. Zythryn

    Zythryn Senior Member

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    No, there is simply no comparison.
    If your friend is spending $70k+ on cars, ask him to go with you to test drive a Tesla performance model 3. When you get there, have him try as well. Same cost (before any rebates) and far better performance. There is simply no comparison.
    Idling at a higher RPM will make it better, but still not in the same ballpark.
     
  18. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    yeah it'll be closer, but you'd still know the difference. And yes, it completely savages your MPG, not just a dip.

    I'm just going to suggest that you work on evangelizing the 0-10MPH time metric among automotive journals. Alternately a 1-meter drag race.
     
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