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calculated vs. computer MPG - Please post your results

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

  1. Cparker

    Cparker Junior Member

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    I've only had my 2014 Prius 4 days, and am experimenting with the power versus economy modes to see what the difference is in MPG. I did the same trip, one in economy , one in power and the dash readout said 49 mpg both trips. Mixed city and freeway. How is this possible ? Anyone else do this ?
     
  2. Grit

    Grit Senior Member

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    Same results here. You hea/rd this already "depends on your driving style," "traffic," "speed limit" and etc. You can be on ECO mode and mash the accelerator far down quickly to get up to ta/rget MPG then ease back on accelerator for EV kick in would be simila/r to lightly pressing accelorator down in power mode to reach ta/rget MPH and ease back on accelorator for EV mode to kick in. 2 different pedal styles but similar MPGs. Hills, winds, temp and other factors will get you different results of course.
     
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  3. Cparker

    Cparker Junior Member

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    My 2014 Prius computer read 52
    mpg, calculated 49 mpg. My 2014 Toyota Yaris computer was much more accurate . I was hoping all Toyota's use the same computer, but I guess not. Still happy with the mileage ,which is at least 10 mpg more than I was getting in the Yaris, even during winter months.
     
  4. 4est

    4est Active Member

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    On my left full tank the real consumption was 10% higher compared to computed

    I see that in winter the difference is even higher than in the summer
     
  5. bentbow

    bentbow Junior Member

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    Wondering, has anyone considered the gas pump might be little off [to charge you a little more] or maybe odometer is a tiny bit off [due to tire variables]. I know these are very small variables but over 600 miles and 12 gallons of gas, that might account for 2-3% MPG difference
     
  6. KokomoKid

    KokomoKid Member

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    I suspect today's gas pumps are pretty accuate, and if you use different ones, it should all average out. I had a 2010 Prius, and now have a 2017. The readouts of both have been 4-5% high, compared to calculated mpg for thousands of miles of driving. The odometers of both cars are within 1%, with newish OEM tires. I'm sure they intentionally make the readouts a little "optimistic," to make people think they are getting better mileage than the are really getting.

    SM-G950U ?
     
  7. 4est

    4est Active Member

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    I have driven many cars, prius is by far the most...let's say "optimistic"

    We accuse Vw for diesel gate, but obviously toyota is intentionally doing something similar here...
     
  8. KokomoKid

    KokomoKid Member

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    Most cars I've had with mpg readouts gave "optimistic" numbers. The exception is a 2016 Corvette, which is only about 1% high over about 3000 miles. People don't buy Corvettes for gas mileage, but the mpg, especially highway, is impressive, about 29.5 for an 1100 mile trip, going 75-80 on the interstate.

    SM-G950U ?
     
  9. KokomoKid

    KokomoKid Member

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    Toyota isn't intentionally fouling the air with emissions that cause smog and health issues, that I know of.

    SM-G950U ?
     
  10. AliPK

    AliPK Member

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    Prius jdm 2013.year and half driven. Average 20.35 km/L.
     
  11. Kthi

    Kthi Junior Member

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    is that the computer average or calculated average. If it's calculated, what is the computer?
     
  12. AliPK

    AliPK Member

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    Manually calculated. I don't even bother to look at on board mpg since it's always too optimistic
     
  13. quantumy

    quantumy Member

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    Last fill-up results
    Trip computer: 44.1 MPG
    Actual Calculated: 41.7 MPG
    402 miles, 9.648 gal

    Mostly city street driving, avg 20-25mph by PC (actually mixed 40 mph and 70 mph with frequent stops in hilly areas), 15 min trips. OEM Yokohama tires at 33,000 miles (~3-4/32nds in left tread, mostly even wear). It's been consistently optimistic on the trip computer, but MPG went up a couple %s after oil change and engine & cabin filter change recently. This last trip was without using any preset modes (eco, power).
     
  14. Ellen Berman

    Ellen Berman Junior Member

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    I replaced Air filter, oil change, and putfuel injector in and increased mog from 40 to 50
     
  15. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Fuel injector cleaner is the one I'd put my money on, as the reason for the mpg increase.
     
  16. Starship16

    Starship16 Senior Member

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    Mendel, don't discourage people from changing their air filter. :ROFLMAO: And I'm going to send you a new one for Christmas!

    My calculated mpg is always 2 or 3 mpg less than the computer. But I'm not complaining. This mpg is when my Prius was only about 4 months old. I never saw those kinds of numbers again. I think the computer likes to tease new owners. :LOL:
     

    Attached Files:

    #1236 Starship16, Oct 2, 2018
    Last edited: Oct 2, 2018
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  17. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    With a third gen with 17" Michelin Pilots I can't get anywhere near that mpg. But I'm ok with that.

    Here's a little reading on air filters, when to change. I'm not kidding that my engine air filter looks near new; don't make me post a picture, lol. The cabin air filter: not so much, but meh...

    Clean vs. Dirty Air Filter MPG. | CleanMPG
     
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  18. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Ok, I snapped:

    IMG_9439.JPG
    ^ This angle shows the dirt the most, but still very minor. Maybe at 100K kms it'll be time. IMG_9440.JPG IMG_9441.JPG
     
    #1238 Mendel Leisk, Oct 2, 2018
    Last edited: Oct 2, 2018
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  19. Starship16

    Starship16 Senior Member

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  20. Grit

    Grit Senior Member

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    :ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO: