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Let's be honest: 691HP in an ICE is Equivalent to 463hp in an EV

Discussion in 'Model S: Driving Dynamics' started by MartinScorpio, Nov 1, 2015.

  1. MartinScorpio

    MartinScorpio Member

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    EV has more torque, flatter torque curve, no gearbox, hence lower drivertrain losses.

    Which makes 1hp in EV power equivalent in performance terms to 1,3hp in an ICE.

    See for yourselves folks.

    Here: 0-60 mph Calculator for Cars

    [​IMG]
     
  2. yo mama

    yo mama Member

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    I hear ya. But it appears that truth in advertising is equally important as actual performance, for some people.
     
  3. Laserbrain

    Laserbrain Member

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    Does not work when you consider speeds above 60 mph.
     
  4. J1mbo

    J1mbo Member

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    In which gear?
     
  5. rns-e

    rns-e Member

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    The right one - the thing about gears is that you can change them in order to have best performance at a given moment. It is amazing how owning a Tesla makes you forget that :)
     
  6. LetsGoFast

    LetsGoFast Active Member

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    The calculator is just using statistical averages. There are many performance ICE cars that also have 1.3 hp per hp using this kind of crazy calculation. For instance the 2014 Porsche 911 S Turbo has 560 HP in a rear wheel drive car weighing 3,693 lbs. The calculator says it should do 0-60 in 3.44 seconds, but it actually does it 2.6 seconds. This doesn't mean it has more HP, it means it has better launch control. Horsepower is not normally the limiting factor in a car's 0-60 performance and this calculator isn't accurate for the purpose you are putting it to. Using the same logic, Porsche HP is the equivilent of 810 HP in a 560 HP car (or 1.45 to 1).
     
  7. Caligula

    Caligula Member

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    Said car has a rear mounted engine in a RWD configuration, so the DT loss will be significantly lower than a RWD car with a front mounted engine.
     
  8. J1mbo

    J1mbo Member

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    The thing about gears is that they have very little to do with HP :)

    If the average ICE had the same gearing as the Model S then it wouldn't get to 60 mph (~7800rpm in the S, depending on tyre size), let alone be able to pass anything.

    But the ICE would be quite good at overtaking between 20-30 mph. If it could get off the line at all.
     
  9. JST

    JST Active Member

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  10. LetsGoFast

    LetsGoFast Active Member

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    That does probably account for some percentage of the difference, but it is quite well-known in performance car circles that 0-60 has become much more of a measurement of launch control than drivetrain performance. See, for instance this Jalopnik article.

    Furthermore, you could use the same exact explanation for Tesla's performance. Drivetrain loss will be even less in the Model S with essentially a direct drive connection.
     
  11. Caligula

    Caligula Member

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    I was simply stating a fact, I wasn't trying to make a point. Sorry for the confusion. Also 60' time is much more important than 0-60 times in terms of off the line traction analysis, IMO.
     
  12. sorka

    sorka Active Member

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    #12 sorka, Nov 3, 2015
    Last edited by a moderator: Mar 13, 2016
    I agree with you when it comes to 0-60. The flat torque curve means the EV can put down more power earlier and achieve the same 0-60 result as the ICE car that has way more peak power but has to first get up to peak power.

    But once the ICE gets up to peak power, it's multi speed transmission can keep it near the peak as it accelerates through the gears and that difference mostly vanishes. The AWD tesla is still more efficient only losing about 10% from battery to wheels vs say the RS7's 17% drive train loss from crankshaft to wheels.


    This chart is a perfect example which supports your claim:

    CRO_Cars_Hellcat_Chart_06-15.png

    But after 60 MPH it's all over for the P85D as the Hellcat is putting out 50% more power to the wheels throughout most of the 1/4 mile run.

    The P85D from 60 MPH accelerates like a 5000 lb car that makes 480 hp (at 30% SOC) to 555 hp (at 90% SOC).

    Another example. Watch this P85D and Mustang 5.0 race from a start. The race starts at 24 seconds into the video. The P85D kills the Mustang off the line. Now skip ahead to 2:24 and watch them race from 60 MPH. The



    The 435 hp Mustang has about the same power to weight ratio as the 480 to 555 P8D provided the P85D is nearly fully charged.

    So from highway roll-on speed, this claim clearly is not true but from 0-60, given that the time to accelerate from one speed to another is based on the amount of power put down under the curve, and given the EV has so much more torque, i.e power at lower RPMs, it is true.

    That's why I'd pick the P85D from stop light to stop light over almost anything else out there but on the open highway it's another story.
     
  13. sorka

    sorka Active Member

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    Geez. Guess I was late to the party. So now we have real shaft numbers instead of battery numbers.
     
  14. aus

    aus Member

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    Thank you. Someone here who's not fixated on 0-60 times. It's more about traction than anything else.
    Many here seem to think nothing else happens after 60mph.
    .
     
  15. MartinScorpio

    MartinScorpio Member

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    Interesting comments.

    Obviously the relatively low gearing of Tesla helps in the 0-60 region, and hinders higher up. But that's a design choice which can be altered. Low gearing in the rear engine and higher gearing in the front engine could lead to a Tesla 90DL beating a hellcat also in the 60-100 region. As the speed goes up, more and more of the power would transfer from back to front engine, effectively giving two gears.
     
  16. chriSharek

    chriSharek Member

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    How about the loss of momentum and time during the ICE shifts? Even in my Volt I can pull away from some cars when they shift.

    I mention this because it certainly has an impact on the 0-60 times.
     
  17. lolachampcar

    lolachampcar Active Member

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    I gotta take some of you gals/guys for a McLaren ride (with only 615 hp) :)
     
  18. Dennis87

    Dennis87 Member

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    McLaren is rwd? So will not be easy to launch as good as a power full 4wd car.

    Try to drag race a 560hp (480 whp) Audi RS7. They are almost the same from 0-60 and 0-100 mph. After that the RS7 pulls away. The weight difference is 150kg less for the RS7.

    Luxury Super Sports Sedan Comparison - Audi RS7, Mercedes-Benz CLS63 AMG S, Porsche Panamera Turbo - Motor Trend All Pages


    From that test the RS7 does 0-60 with rollout in 3.2 sec, the 0-30 mph is also almost the same as P85D. So to say that the P85D performs like a almost 700hp ICE is not correct.
     
  19. scottf200

    scottf200 Active Member

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  20. rns-e

    rns-e Member

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    #20 rns-e, Nov 4, 2015
    Last edited: Nov 4, 2015
    Well Hellcat is not the car that would be natural to compare with. As Dennis87 says, take an Audi RS7, which is a direct competitor to the P85D and see what happens.

    - - - Updated - - -

    With the newest automatic transmissions in Audi, MB, BMW, Porsche etc. you will not be able to register any loos from the shift and from 0-60 mph it may only be one shift anyway. We are talking 8 ms pr. shift - 0.008s to shift gears
     

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