Is 45.8 mpg a good average?

Discussion in 'Gen 2 Prius Fuel Economy' started by Fredsimm, Nov 30, 2017.

  1. Fredsimm

    Fredsimm Junior Member

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    07 base model. Had it about 5 months. I have tried all the tricks. No lead foot, coasting, and cruise control 90% of the time. I stay at 45.8 mpg 99% of the time on the lie-o-meter. Driving is 70% highway and 30% city. Is this considered good, average, or poor?
     
  2. MelonPrius

    MelonPrius Member

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    Slightly above average. Fuelly average of the '07 model is 43.6 mpg here.
     
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  3. egg_salad

    egg_salad Member

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    I'm only on my 4th tank, but here's what I know.

    My speedo/odo reads about 3% low. When the speedometer reads 67, I am actually going 65 per my GPS. That discrepancy is figured in to my hand calculations.

    By those calculations, I have had 3 tanks at ~53mpg and 1 tank at ~47. That's slightly lower than what the MFD tells me, but it's using perceived distance traveled, not actual distance traveled.
     
  4. ETC(SS)

    ETC(SS) The other One Percenter.....

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    Pends....

    What did you get on your last car? ;)

    I'd say that 45mpg in a ten year old car is pretty stinkin good, especially with your mix of highway and city driving and cruise control use.
    If you hand fly the car and stay off the highway, you will leg it up a bit, but I'd take your current mileage to the bank and relax and enjoy the car!!
    Keep your oil level checked (book says every 1,000 miles) and familiarize yourself with the maintenance schedule, and this could EASILY be the most economical car you will ever own!

    Good Luck!
     
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  5. fuzzy1

    fuzzy1 Senior Member

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    Correction: Your speedometer reads high, not low. I.e. it reads higher than actual speed.

    Beware that speedometer and odometer errors are not the same -- and deliberately so. Calibrate them separately.

    Speed error does not figure in to MPG at all, unless you are charting MPG vs MPH.

    By industry standards, and by law in some places, speedometers must not read low (from the factory with original tires), they must read true or high. Given that there must be some error, especially with old fashioned analog systems of the old era, the makers biased them high.

    By American tort law, odometers must not read high, because product liability lawyers will come after the makers for warranty fraud. BTDT on two past cars (my particular cars were fine, but the lawyers still collected a significant payday).

    Thus, today's speedometers and odometers generally don't match, but have different built-in errors.
     
    #5 fuzzy1, Nov 30, 2017
    Last edited: Dec 1, 2017
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  6. egg_salad

    egg_salad Member

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    This is why math and I are not friends.

    I'm old :)

    I will take an odometer calibration run as soon as practical. thank you.
     
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  7. fuzzy1

    fuzzy1 Senior Member

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    I was an engineer during my working life, so had to do math by the (metric) ton.
     
  8. WilDavis

    WilDavis Senior Member

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    Looks good to me! My overall (from "fuely") is ~44 (2009 Gen II) 177 fill-ups, I've owned the car since Jan 2014. I would say keep on doin' what yer doin'. :)
     
  9. jerrymildred

    jerrymildred Senior Member

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    This is probably the biggest factor. That's assuming you're familiar with tire pressures and the other ways to save fuel. I'd say, under your driving conditions, you're about right. Not spectacular, but not bad at all.
     
  10. Fredsimm

    Fredsimm Junior Member

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    Thanks everyone. I just heard people boasting about staying in the low 50's. I thought that I was missing something.
     
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  11. egg_salad

    egg_salad Member

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    Did that today. Odometer is spot on within a reasonable margin of error. First test the odometer read 99% of actual miles. Second test was 99.667%. I'm calling that accurate.
     
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  12. bisco

    bisco cookie crumbler

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    i think so.
     
  13. frodoz737

    frodoz737 Top Wrench

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    That's because most Prius drivers here like to "boast" about "their" MPG trophies. Even the 3rd Gen is lucky to hit 50 "real" mpg when driven "normal". I did 61.9 mpg "indicated" once and pissed off every truck and car on the Interstate to do it. I can live with 40 something mpg because driving "normal" in other cars usually gives low 20's. So...either way it's a win...until you need a truck that is.
     
  14. egg_salad

    egg_salad Member

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    I do not know. I drive the same way I always have, and hit the low 50s. Then again, I've always driven like your grandmother, and I've always exceeded EPA numbers :)
     
  15. fuzzy1

    fuzzy1 Senior Member

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    I.e. different than you speedometer, and in the opposite direction.

    Over a pair of I-90 sections covering most of the160-miles distance from the Columbia River to the Idaho border (beware of a major milepost 'bust' at Ritzville), my current and previous Prius were between 99.7 and 99.8%. But I haven't tracked close enough to notice differences with tire wear.
     
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