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What is a reasonable expection of fe

Discussion in 'Gen 2 Prius Fuel Economy' started by 1965GTO, Dec 15, 2017.

  1. 1965GTO

    1965GTO New Member

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    I am averaging about 38 mpg for temps in the mid 30's. Is this a reasonable average? Should I expect more? I have an 08 with 171k
     
  2. bat4255

    bat4255 2017 Prius v #2 and 2008 Gen II #2

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    Sounds normal to me.
    My formula for all my vehicles, take your Best mileage in summer
    Assuming 50 mpg
    -10% for low temps 20 (f) - 60 (f)
    -10% for winter gas
    -10% for short trips (not warmed up yet)
    -10% for really cold weather < 20 degrees (f) or a moderate to strong headwind.
    So worst case would be about 30 mpg
    I'ts still almost dbl. than the average vehicle
     
    #2 bat4255, Dec 15, 2017
    Last edited: Dec 15, 2017
  3. bisco

    bisco cookie crumbler

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    there are so many variables, it is hard to say what is reasonable.
     
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  4. egg_salad

    egg_salad Active Member

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    If you're happy then it's reasonable. If you're not happy, it's unreasonable.
     
  5. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    My gen 2 averaged 42 MPG, but I am in MS and that is a warmer state.
     
  6. fuzzy1

    fuzzy1 Senior Member

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  7. wjtracy

    wjtracy Senior Member

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    38 is what is showing on my screen right now...if we took a long trip it could go to 45-50.
    We are only getting about 6.5 gal in guess tank now too on fill-ups.
    Car is aging faster than me and that ain't easy.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Is that calculated or displayed? If displayed, actual is likely lower. Maybe someone can comment as to the second gen fudge factor?
     
  9. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    My gen 2 had under a 5% fudge factor, but was wildly inaccurate per tank, you needed to average tanks to get MPG.
     
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  10. valde3

    valde3 Senior Member

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    Like bisco already said. Fuel economy depends on lots of things.

    Even in temperatures colder than -10c or 14F you can still get 3.8l/100km or 62MPG if you drive trips that are long enough with average speed that’s not too low or too high and you don’t use heater on too hot of a setting.

    But you can also get 10l/100km or 24MPG if you drive short trips, with low speed or heater on too high of a setting.
     
  11. 1965GTO

    1965GTO New Member

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    The MPG is displayed not calculated. I understand there are many variables that affect the FE. I have read extensively here and I was just curious if it is within a reasonable range for winter. The car is new to me. I am a used car dealer and it is for sale however, I plan on driving it quite a bit. My regular vehicle is an 03 Tahoe so anything over 14 MPG for city driving is a bonus. I am seriously enjoying the drastic increase in FE.
    I am driving very conservatively but not attempting to hypermile. The MPG I was asking about is all city driving and mostly very short trips at that. I live about 4 miles from my business and all the other trips are predominately 5 miles or less. Occasionally there is the 10-12 mile errand. The past couple of days I have driven with the HVAC off and that is making a difference. It stays in ev mode much more. The tires are inflated to max listed on the tire. IDR the exact pressure. Oil is level is right on full. Where I live is gentle rolling hills. Oh and I do have the Torque app with the Prius PIDs installed.
    Thanks for the help and input!
     
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    So maybe 36 mpg calculated, assuming aforementioned 5% factor.


    Predominantly 4 mile trips is probably the kicker, though not that bad. Some of our shorties are grocery runs, 2 kms overall. :cry:

    Yeah, avoid AC use like the plague. Can you run HVAC without AC: that's preferable.

    Just for giggles, feel all the wheels after a drive, make sure none are overly hot, brake drag?
     
  13. fuzzy1

    fuzzy1 Senior Member

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    With these conditions, your overall MPG seems quite reasonable.
     
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  14. WilDavis

    WilDavis Senior Member

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    …as can be seen from my Fuelly stats, my last couple of fillups have been in the 30s, but the weather here in the NE USA has been bloody cold, and I've been using the heater more than normal - that plus winter gas formula and lots of short trips might be responsible (at least for my stats!) :( ;)
     
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  15. Tideland Prius

    Tideland Prius Moderator of the North
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    Yeah for trips less than 10 miles, that sounds about right because the engine has to warm up. In the summer, you may be able to bump it up to mid to high 40s.

    Take a longer trip (say 20 miles one way) and you'll find the mpg will improve dramatically because now you're able to take advantage of a warmer engine (assuming it's not 0°F outside that is... I'm thinking when temps are above freezing).

    Also note that there's a software check on the Gen 2 that's done once the engine is lukewarm but it requires the car to come to a complete stop before the engine will shut down for the first time. If you're just rolling in traffic or just never stop at a traffic light, then the engine will continue to idle. It's been improved on newer Prii (starting with Gen 3 where it can do the check while the car is still in motion and therefore can do the initial engine shut off).

    I found our Gen 2 was pretty accurate. YMMV.
     
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  16. srellim234

    srellim234 Senior Member

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    It looks to me as if your fuel economy is right where it should be. Your driving is similar to ours in the wintertime when the car rarely gets to the open highway and spends most of its time on 1 to 5 mile quick jaunts around town.. In the warmer climate of southern California we often get tanks calculated between 33 and 38 U.S. mpg. then. We still get in the mid to upper 40's on our longer trips, hence our overall average at 42.9 or 43.0 mpg. 43 is in line with the overall averages at fueleconomy.gov and fuelly.com so we don't sweat those tanks in the mid 30s.

    And yes, the mpg on the screen is often overstated by a little. On our car it's done that about 2/3 of the time. The other 1/3 has been understated or spot on.

    EDIT: Edited to correct the last line of the first paragraph.
     
    #16 srellim234, Dec 16, 2017
    Last edited: Dec 16, 2017
  17. 1965GTO

    1965GTO New Member

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    Thanks for the responses. I was thinking I was in a normal range however I just wanted to confirm it with the seasoned veterans.
    I am starting to like the Prius and I am used to a large SUV as my regular vehicle (Tahoe). I love everything about it except the atrocious FE.
    I now understand how maximizing the FE in the Prius can quickly become an obsession!
     
  18. bisco

    bisco cookie crumbler

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    a 20 mile trip at 30-40 mph, without too many stops should net you 45-50 mpg.
     
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  19. uart

    uart Senior Member

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    TBH at those sort of speeds I'd be in the high 50's, or about 4.0 L/100km. :)
     
  20. srellim234

    srellim234 Senior Member

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    Are you referring to UK gallons or US gallons?