calculated vs. computer MPG - Please post your results

Discussion in 'Gen 3 Prius Fuel Economy' started by F8L, Jul 10, 2009.

  1. CR94

    CR94 Senior Member

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    As a long-term weighted average, actual=0.956 of indicated mpg, very consistently.
     
    #1201 CR94, Nov 8, 2017
    Last edited: Nov 9, 2017
  2. 70AARCUDA

    70AARCUDA Active Member

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    That's what I'm getting for our 2014 Prius-IV at just under 40K miles.
     
  3. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    61 pages of consistent inconsistency, @Prius Team ?
     
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  4. CR94

    CR94 Senior Member

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    Yes,car to càr. An individual car should be consistent. Some owners have trouble with the math to get a true average,
     
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  5. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    My error dances around a bit, but settled in on 7.5% positive bias. Wayne Gerdes had a pre-production fourth gen for testing, and he found the displayed mpg virtually identical. But owners of (production) fourth gens are reporting more-or-less the usual positive bias, IIRC.
     
  6. Jim7

    Jim7 New Member

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    That's been my experience for the last 90,000 miles (we took over our daughter's lease at 45,000, have 142,000mi on it now). If I show 48mpg on the computer for example, it's about 45.5 - 46 actual, or right on the money. In winter of course it's less, we're in the NE.
     
  7. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    My latest tank is a highwater mark in inaccuracy. Maybe pump ran on a bit, I'll see if it balances out on the next:

    upload_2017-11-16_18-45-32.png

    Feeling the effects of colder weather, short trips and snow tires too I guess.
     
  8. Terrell

    Terrell Member

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    After 78,000 miles, the indicated MPG averages about 6.55% too high, bouncing around quite a bit.
     
  9. enerjazz

    enerjazz Energy+Jazz=EnerJazz

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    I've been tracking display bias across a 2004, then 2007 Prius for over 13 years. Here's the data: [​IMG]
     
  10. 4est

    4est Active Member

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    Mine is ~8% too optimistic Vs reality
     
  11. danpriusman

    danpriusman Junior Member

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    I have been tracking the mileage and found that there is a consistent 6-7 mpg difference. The computer will calculate 54 and I get 48 after fill-ups. From reading other posts most people get greater than 50 mpg with their Prius. I drive in a very conservative manner using hypermiling techniques where available. Does anyone else have lower numbers?
    thanks
     
  12. jerrymildred

    jerrymildred Senior Member

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    Welcome, Dan. Quite a few people here get similar numbers. Here are the stats for the Prius on Fuelly.com. Average for the 2010 is 45.3 mpg.
     
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  13. Oskar

    Oskar Member

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    I found that it varies if, when filling up, you stop when the pump shuts off, or if you top-it-off. I always stop when the pump shuts, just to keep it consistent. But I, like others here, have the same discrepancies between what the read-out states, and my own calculations at the pump.
     
  14. 4est

    4est Active Member

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    I also drive a diesel bmw. The estimated consumption from the computer is spot on
    The car's ecu knows EXACTLY how much fuel it uses
    So the displayed mpg is purposely wrong, to make drivers happier!
     
  15. Steves895

    Steves895 Member

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    Filled up today, display indicated 59.9, Fuelly calculated at 57.5.
     
  16. Dxta

    Dxta Senior Member

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    Please what foes the LIFETIME MPG mean?
     
  17. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    For me, it's all the gas I've put in, divided into all the miles traveled. Well, I'm doing liters per 100 km, but same thing. Also, I didn't track the first 2154 kilometers, but I've stuck with it since.
     
  18. Dxta

    Dxta Senior Member

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    Thanks a lot!
     
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  19. Bob L

    Bob L New Member

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    I have a 2013 Prius. My figuring my mpg on my own versus the car computer generally shows the car computer overestimates to my calculations about 2-4 mpg.
     
  20. Bob L

    Bob L New Member

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    I have done this about 20 times. Also, mpg is much worse the colder it is.
     
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