Speed at which the Prius and Prius C have the same gas efficiency

Discussion in 'Prius c Technical Discussion' started by kalsifur, Sep 17, 2014.

  1. kalsifur

    kalsifur Junior Member

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    The Prius has EPA MPG of 51/48 and the Prius C is at 53/46. At what speed (where the speed is higher than typical city speeds but lower than typical highway speeds) would both the Prius and Prius C have the same MPG? In other words, at what speed would their speed-to-MPG curves intersect?
     
  2. ztanos

    ztanos All-around Geek!

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    I think the question that really needs answered is what is the speed at which they would be the same for an African and European unladen Prius.
     
  3. ztanos

    ztanos All-around Geek!

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    But in all seriousness, I would imagine it's somewhere between 65-70.
     
  4. Bill the Engineer

    Bill the Engineer Senior Member

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    Totally depends on how you drive them. I would think that the same driver who drives both cars hard would have much different results than another driver who hypermiles both cars. I don't think the cross-over point is fixed, since there are other considerations like vehicle weight (inertia) and available horsepower to factor in.

    Bill the Engineer
     
  5. ztanos

    ztanos All-around Geek!

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    I think what he is asking is as what speed... using cruise control on a level terrain on the highway... would the two cars intersect for MPGs. It shouldn't totally depend on how you drive them. At 70 the Prius gets better gas mileage... but at 55 the PC gets better gas mileage.
     
  6. kalsifur

    kalsifur Junior Member

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    Yes ztanos that is what I'm trying to determine. For now, I'll approximate the speed at which both cars have the same MPG as the halfway point between 55 and 70, or 62.5 MPH.

    Since I maintain 60 MPH on highways, the Prius would offer me no additional highway fuel savings at that speed, and may even be very slightly less efficient. Also, as a data point, I find that driving at a constant 60 MPH for 45 minutes or more yields 60 MPG, which I think of as "60 for 60."
     
    #6 kalsifur, Sep 18, 2014
    Last edited: Sep 18, 2014
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  7. bisco

    bisco cookie crumbler

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    try 65 and see what happens, you might be surprised.
     
  8. ztanos

    ztanos All-around Geek!

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    It won't be 65 mpgs, lol. It won't be 60 either. Ha ha ha.
     
  9. priusCpilot

    priusCpilot Active Member

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    Steady state speed for both cars. 2014_Toyota_Prius_5_-_Speed_vs_FE.jpg 2014_Toyota_Prius_c_Speed_vs_FE.jpg
     
  10. ztanos

    ztanos All-around Geek!

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    So this is saying that the PC is more efficient at 70 mph?
     
  11. priusCpilot

    priusCpilot Active Member

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    Yes but the 3rd Gen tested was with the factory 17" wheels.
     
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  12. smackdownC

    smackdownC Junior Member

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    The liftback is def more fuel efficient on the hwy for obv reasons. I've driven both a day apart. The C tends to get into the PWR way more than the C, so at 70 mph, the liftback is a few mpg better. The C is more fuel efficient if you keep it under 65 mph, but that's tough on hwy's when the speed of traffic is 70+.
     
  13. Mark323

    Mark323 Junior Member

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    Potato Puh-tato
     
  14. cyclopathic

    cyclopathic Senior Member

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    it's a big if.. no info on which tires? pressures?
    FuelMax is not the best LRR, our hatchback gets considerably better MPG then PC even at low speeds. Blame low temps and tires.
     
  15. JayLn

    JayLn Active Member

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    Not to tell you can not recreate the same traffic condition when you tested the 2nd car.
     
  16. cyclopathic

    cyclopathic Senior Member

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    IMHO it isn't as much about speed as it is about temperature. "C" may get upper hand when temperatures over 60F, but drop it below low-40s and Gen3 will have it for breakfast.
     
  17. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    You are all way overthinking this.

    The obvious answer: 0.
     
  18. Motov8r

    Motov8r Member

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    This can be overcome by grill blocking.


    iPhone ?
     
  19. cyclopathic

    cyclopathic Senior Member

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    unfortunately no. And not for lack of trying
     
  20. ursle

    ursle Gas miser

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    Tony is correct, amazingly
     
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