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what am i doing wrong?

Discussion in 'Prius c Fuel Economy' started by hieuous, Jul 6, 2013.

  1. hieuous

    hieuous New Member

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    no matter how hard I drive I can't get the car to maintain anything over 40 mpg, of course unless i drive like a grandma and drive way under the speedlimit which is 45.

    I don't mash the gas, I don't go crazy at stop lights, I drive like a normal person. The roads in vegas aren't the flattest things in the world but it isn't horribly hilly here either. I don't know what i'm doing wrong.

    also, i just bought the car three days ago. and yes, i have seen the youtube video and employ the techniques whenever i can.
     
  2. Vegas is currently 100-110 degrees. Extremely high temperatures such as over 100 degrees will probably require you to run the air conditioner, which uses energy and thus decreases your fuel economy.
     
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    1) begin worrying about gas mileage on the third tank, you should be familiarizing yourself with the controls and blind spots. Aim the mirrors, learn the dash adjust the driving position, etc. These are safety measures, but gas mileage is not.

    2) if you are going to change your driving in any way, work on using the brakes less.
     
  4. hieuous

    hieuous New Member

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    by that much?
     
  5. It could. How far do you go in each trip? 5 miles? 20 miles? What's a typical trip for you?
     
  6. hieuous

    hieuous New Member

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    i've been doing varying trips to see if at any point i could maintain over 40MPG for the whole trip. on wednesday drove about 127 miles and got 36.7 mpg. most of it was freeway too.
     
  7. How fast are you going on the freeway? How many times do you find yourself having to "fight traffic" on the freeway?
     
  8. hieuous

    hieuous New Member

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    about 70-75 whole way with cruise control and ac all the way up.

    do i just have really high expectations?
     

  9. At 70-75 mph, your fuel economy will be in the 40 mpg range. With AC full blast, you can expect your fuel economy to drop a little further. If you are fighting traffic, you will probably find yourself stepping on and off the gas irradically, which uses more gas.

    Slow down to 55 mph. Keep ECO mode on. Lower your AC to half instead of full blast. Pick the slow(er) lane and let people pass you if they're in a hurry.

    For reference, I did a 150 mile freeway trip (light hills) with the AC at low-ish and at 55 mph and I got almost 60 mpg.
     
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  10. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I am not at all sure I would have bought a city car in Vegas, but you have it now.
    It does not have as good as aerodynamics as the liftback so higher speeds will effect it more. But I do 71 all day long and do about 42 in a v which is even less aerodynamic.
    Do not skimp on the A/C even if it hurts MPG, the batteries are in the car with you and need to stay cool to last for a decade.

    Be sure the tire are inflated. I suggest 38 in front/36 in back.
    Smooth cruising, and gentle deceleration are your friends on the freeway. Ideally you never touch the brake pedal.
     
  11. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    This is a liftback graph so the numbers will not be accurate, but the curve tells the speed tale:
    [​IMG]
     
  12. hieuous

    hieuous New Member

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    70 is the posted speed limit, I don't think i can go lower than that otherwise people would suddenly notice their horns. I guess i had too high expectations
     
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  13. hieuous

    hieuous New Member

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    hmmm. according to this graph i should be getting about 50-60 mpg going 45 mph. I havn't seen those numbers yet though, my car stays steady at 37.6 or so.
     
  14. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Darn. I tried to tell you not to pay attention to the numbers (this is not your car) but to look at the slope as speed increases. Since your (and my) car actually have worse aerodynamics than the liftback, our slope should be even steeper.
     
  15. hieuous

    hieuous New Member

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    ahh. sorry. i just didn't think there would be that much of a difference...

    i mean at 45 miles an hour and at 70 mph i'm getting less than 40 mpg it just confuses me.
     
  16. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Unless posted, Nevada has no set minimum speed, you are just supposed to not be dangerous.

    Here in MS, when the speed limit is 70, the minimum posted is 40. I go 71 MPH personally, to match the semis. (in the v, that is about 43 MPG)
     
  17. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I lived for 14 years in Elko, you have way different weather in Vegas, but low temps hurt gas mileage, then it improves to about 85 degrees, then slopes back down above that because we use A/C. I get my very best mileage in spring and fall.

    Your c is still stock, right? You have not put 'stupid big' wheels and tires or roof racks or anything, right? And you have checked the tire pressure?
     
  18. hieuous

    hieuous New Member

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    i'm not so much concerned about the 70 mph trips that I understand that the mpg won't be as high; i'm much more concerned about the lower speed mpg issue i'm having and whether or not i'm just being a crazy girl right now.
    yep, it's still stock, nothing done to it. i haven't checked tire pressure yet but i will when i get home.

    i wish i could do a test run without ac but it's so insanely hot this year that's unfathomable. though i'm going to comic con in two weeks so maybe i can then.
     
  19. There's really nothing to fret about. It's 100+ degrees so running the AC full blast is part of why your fuel economy is lower. (Inside the car I bet it feels like 110... I would go crazy if it got that hot)
    So far, it sounds like the car is doing its job just fine.
    As for the "lower speed mpg issue" - that's harder to gauge without knowing what your "typical trip" is like. Are they short trips? How much time are you spending at traffic lights? How much do you "step on the gas"? How many miles do you go per trip?

    (Edit: I just thought I'd mention that there are a lot of factors that go into "city driving" so that's why I'm asking a lot of Qs. For me, my city trip economy can vary anywhere from 20s to 60s. Dealing with impatient drivers is a big factor.)
     
  20. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Never adjust the tire pressure higher than that marked on the tire itself.

    Higher pressures give better MPG and handling, lower pressures give better ride.

    In general, Toyota tries to choose to maximize ride comfort. Your tires should always be at LEAST as high as Toyota's spec.