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Calculated MPG vs. Indicated MPG of the c - Please post your results

Discussion in 'Prius c Fuel Economy' started by F8L, Mar 11, 2012.

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  1. Kirkuleez

    Kirkuleez New Member

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    You're welcome F8L. My first tank was about 2.5% off with the car computer being high again.
     
    #21 Kirkuleez, Mar 19, 2012
  2. vinnie97

    vinnie97 Whatever Works

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    I guess I will have to try to emulate Wayne's topoff procedure.
     
    #22 vinnie97, Mar 19, 2012
  3. F8L

    F8L Protecting Habitat & AG Lands

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    Once I get a few more tanks under my belt I may try it too.
     
    #23 F8L, Mar 19, 2012
  4. JeffHastings

    JeffHastings Member

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    Much agreed, despite that I like a fair number of GM vehicles.
     
    #24 JeffHastings, Mar 19, 2012
  5. TomDac

    TomDac Junior Member

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    Currently on my 4th tank of gas and so far, the indicated MPG is about 2 MPG higher than manual calculations... My first tank of gas I only calculated 38 MPG, and the dealer said not to worry that the MPG would increase.... I can live with the computer being 2 MPG high..


    I'm using an iphone app called "Gas Cubby" to track my MPG manually..
     
    #25 TomDac, Mar 20, 2012
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  6. F8L

    F8L Protecting Habitat & AG Lands

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    Could you please list the actual numbers?

    Use either the format I listed on the first page or this one.


    2012 Prius Three w/solar roof
    Miles= 288.70
    Gallons= 6.573
    MPG Displayed = 46.2
    MPG Calculated= 43.9
    Tires= Yokohama AVID Ascend 42psi front 40psi Rear (brand new)
    Fuel= Costco 87octane with 10% ethanol
    MPG Indicated vs. Calculated= 5.24% difference

    Remarks: This tank was used driving my normal commute of 100miles/day of freeway at 65-75mph.Heavy rain and very windy. Brand new tires and zero attempt at efficient driving.
     
    #26 F8L, Mar 20, 2012
  7. cycledrum

    cycledrum PSOCSOASP

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    What the ???? All of it into a stiff headwind? No offense, but I've never seen that in a 3rd gen Prius, like 12 of them - get them warmed up and there either pushing 50 on gage or little over in Winter/ way over in Summer. Are those LRR / high MPG ties? I guess the wind / rain made a big diff.
     
    #27 cycledrum, Mar 20, 2012
  8. F8L

    F8L Protecting Habitat & AG Lands

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    As Metallica sang, it's sad but true. New car, new tires, lots of water on the road, heavy winds, and fast driving will really destroy mpg. Even in a GenIII. :(
     
    #28 F8L, Mar 21, 2012
  9. Codyroo

    Codyroo Senior Member

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    Rain, wind, cold weather are the Harvester's of Sorrow......
     
    #29 Codyroo, Mar 21, 2012
  10. kwhitty

    kwhitty New Member

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    It's also useful to post mpg results on fueleconomy.org - that way the EPA knows some actual driver results and car buyers are more likely to see it.
     
    #30 kwhitty, Mar 22, 2012
  11. jurgvonschmurg

    jurgvonschmurg Junior Member

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    I haven't had to fill up, but over 450km the car tells me I'm averaging 4.7L/100km, which is just about 50mpg on the nose.
     
    #31 jurgvonschmurg, Mar 24, 2012
  12. cpfans4

    cpfans4 Junior Member

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    my computer says 53 and I calculated it at just under 49 only used 15.1 gallons after 2nd fillup and will have better results. My drive to work is alot of hills up and down...
     
    #32 cpfans4, Mar 24, 2012
  13. F8L

    F8L Protecting Habitat & AG Lands

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    Do you have the exact numbers? That would put you at about 8% over-reporting with the numbers you gave.
     
    #33 F8L, Mar 24, 2012
  14. Kirkuleez

    Kirkuleez New Member

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    Filled up the C again last night. Car indicated 52.2mpg's, after manually calculating 421.2miles on 8.313 gallons comes out to 50.66 actual. That was primarily all rural highway miles on my commute to work.
     
    #34 Kirkuleez, Mar 26, 2012
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  15. F8L

    F8L Protecting Habitat & AG Lands

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    For a 3.03% discrepancy. Not bad. :)
     
    #35 F8L, Mar 26, 2012
  16. Kirkuleez

    Kirkuleez New Member

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    I agree F8L, why is it most cars seem to have that 3 or 4 percent discrepency? I always wonder if it's intentional.
     
    #36 Kirkuleez, Mar 26, 2012
  17. nebulight

    nebulight New Member

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    Vehicle:
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    Model:
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    Year of vehicle: 2012
    Date: 3/26/2012
    Miles driven: 415.6
    Gallons Pumped: 8.640
    Hand-Calculated MPG: 48.1
    Displayed MPG: 56.7
    Average Speed: Forgot to check
    Tire Size / Wheel size:
    Tire Brand / Model:
    Tire PSI (Front / Back):
    Seasonal Conditions: (please include A/C usage and temp setting if applicable)
    Commute Length:
    Hypermiling Techniques: EV mode
    Other: (this could explain why a tank was bad or good or other unusual conditions like a rain storm, new tires, lots of short trips, etc.)

    This is my first fill up and I'm a little disappointed. My computer stated it was 56.7mpg yet when I filled up at the station just now, I calculated it out to only 48.1mpg?? That's almost an 18% difference. The only thing I can assume is that the dealer didn't put a full tank in. But I have no way of knowing. I guess I'll wait until my second fuel up.
     
    #37 nebulight, Mar 26, 2012
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  18. Kirkuleez

    Kirkuleez New Member

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    #38 Kirkuleez, Mar 27, 2012
  19. nebulight

    nebulight New Member

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    Filling until it clicks. I asked around and I guess dealers fill it only until the gauge shows full. Shady, but we'll see on my second tank.


    mobile phone ?
     
    #39 nebulight, Mar 27, 2012
  20. JKahler

    JKahler New Member

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    Location:
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    Vehicle:
    2012 Prius c
    Model:
    Two
    Year of vehicle: 2012
    Date: 3/28/2012
    Miles driven: 330.1
    Gallons Pumped: 6.967
    Hand-Calculated MPG: 47.38
    Displayed MPG: 52.2
    Average Speed:na
    Tire Size / Wheel size:na
    Tire Brand / Model:na
    Tire PSI (Front / Back):na
    Seasonal Conditions: Mostly dry ~50 degrees
    Commute Length: 66 miles
    Hypermiling Techniques: Prius Noob
    Other: This was my first tank (filled by dealer). Half of my miles for this tank were short trips over the weekend with friends, playing around with the car. Commuted once to work (today), which is 66 miles with 80% highway, and got 54 mpg on the way there, but 44 mpg on the way back. Pretty sure the poor results on the way back were due to driving into 25 mph winds and a general upward incline.
     
    #40 JKahler, Mar 28, 2012
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