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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. valde3

    valde3 Senior Member

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    US gallons, as 4.0l/km is 59MPG(US) or 71MPG(UK)

    Actually it’s possible to get that kind of consumption figures in “20 mile trip at 30-40 mph” (30km at 45-65km/h) trip even in those a bit below freezing temperatures with cold start.
     
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  2. uart

    uart Senior Member

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    4.0 L/100 km is approx 58.8 MPG US, and about 70.6 MPG UK. I could get that just about every day of the week if I always drove at 30 to 40 MPH (48 to 64 km/hr).

    Edit. You beat me to it valde. :) I'm pretty slow at typing.
     
    #22 uart, Dec 17, 2017
    Last edited: Dec 17, 2017
  3. srellim234

    srellim234 Senior Member

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    Thanks. I should have done the conversion from liters myself. I'll blame the "not very bright" question on the fact that it's early morning and I haven't fired up the coffee pot yet. :coffee:

    Ours will run in the low 50s on drives like that but I'm not sure it will be in the upper 50s. I've hit over 55 mpg for a tank only twice and blamed both of those on the flexible fuel bladder. :unsure:
     
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Divide either value, us mpg value or liters per 100 km, into 235.2, converts from one to the other:

    235.2/4=58.8
    235.2/58.8=4

    By tweaking that 235.2 value, you could also come up with an imperial mpg conversion factor. The latter is basically relegated to United Kingdom I suppose. Oh, and Canadian car salesman, who are in love with it for some reason, even our country hasn't sold gas by the imperial gallon in many decades.
     
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  5. 1965GTO

    1965GTO New Member

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    A short term update...
    The temps have increased here to upper 40's F and so has my FE. Its creeping up into the low to mid 40's mpg. I am also learning how to drive the car better. I cant wait to see what it gets when the weather gets warm.
    I have noticed that when I turn the heater to recirc. it will default to outside when the car is turned off and restarted. Is that normal? Is there a way to avoid that?
    I like to see the FE reported as gallons/100 miles as well as mpg. Just another angle to look at the same thing.
     
  6. bisco

    bisco cookie crumbler

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    normal. not sure if you can change that with tech stream mini vci or not.
     
  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Cause they advertise a higher mpg and claim "it's the same as the Prius" even though it's a different gallon.
     
  8. valde3

    valde3 Senior Member

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    Why would you want to keep it in recirculation anyways? If it’s below or a bit above freezing recirculation will just fog up the insides of your windows.

    In hot temperature system will automatically use recirculation to reduce the load for AC compressor.
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    I look on recirc similar to holding my breath, just a momentary thing, to get through some diesel's smoke cloud or whatever. Around here, leave it in recirc and you'd be driving in a steamed up terrarium within 2 minutes.
     
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  10. Tideland Prius

    Tideland Prius Moderator of the North
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    If you have the A/C one, recirc won't fog up the windows as the A/C will regulate the humidity. If you have A/C off, then yes, the windows will fog up in a hurry.
     
  11. valde3

    valde3 Senior Member

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    If it’s cold AC won’t help as it can’t cool the condenser below freezing as the condenser would just ice up.
     
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    I find the need to dehumidify decreases as temp drops, works out: by the time the AC compressor refuses to run the air is a lot drier.
     
  13. Tideland Prius

    Tideland Prius Moderator of the North
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    ^ What he said. The specific humidity of air drops as the air temperature drops.

    That changes if you have 4 people in the car with wet boots and snow melting on the floor mats. Then I find the climate control can struggle to keep the top half of the windshield clear (the rear side windows are hopeless) but that's rare for me. (And of course the climate control will not be in recirc).

    I usually just leave everything in AUTO, even with the A/C on (in AUTO).

    Extreme Cold Weather Performance | PriusChat
     
  14. valde3

    valde3 Senior Member

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    I replied to Tideland Prius. Tideland Prius commented that you can keep it in recirculation if you keep the AC on. If the temperature is cold enough AC compressor won’t operate. Even if there is just one person and not a bit of snow windows will fog up eventually if you just keep it in recirculation and AC isn’t operating.
     
    #34 valde3, Dec 23, 2017
    Last edited: Dec 23, 2017
  15. Tideland Prius

    Tideland Prius Moderator of the North
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    Eventually? Yes I agree. It will fog up eventually.

    I wasn't complaining that it said -40°C when it was -45°C. I was just wondering why it went down to -40°C when the manual claimed it was only capable of displaying down to -30°C.
     
  16. valde3

    valde3 Senior Member

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    If you read my earlier post that you replied to and the post by 1965GTO that I was replying to.

    At least I understand that 1965GTO wants to keep it in recirculation mode all the time in cold temperature. And that will fog up the windows.
     
  17. 1965GTO

    1965GTO New Member

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    Not exactly, I just dont want it to default to outside air. I want the default to be whatever I last set it on.
    I understand how to keep the windows free of fog. Geez, I graduated from engineering school....I can figure out how to operate the heater and defroster controls.
     
  18. egg_salad

    egg_salad Active Member

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    This is drifting way off topic, but are you available for tutoring? I'm NOT an engineer, so I can't figure it out for the life of me. The Owner's Manual is less than helpful.
     
  19. valde3

    valde3 Senior Member

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    I wasn’t trying to imply that you don’t know how to operate the heater.

    But I just can’t figure out the situation where you would want it to remain in reticulation mode. Because for that you would both need it to be in recirculation when you shut down the car and you would need a situation at startup when it would be somehow beneficial for it to be in recirculation. Especially for cold temperatures (that this topic started with) this seems very weird thing to want.

    Toyota probably made it automatically turn back into fresh air mode at startup so that you don’t forget (even though there’s an icon on dash) that you left it in recirculation mode and drive around with foggy windows.