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Disappointing hwy MPG

Discussion in 'Prius c Fuel Economy' started by cyclopathic, Nov 17, 2015.

  1. kenoarto

    kenoarto Senior Member

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    Two of us just drove from Chicago to NJ and back in our 2005. Glued at 70mpg for mostly flat miles, 45 degrees outside, heat on, some rain, we got our usual 41.5 mpg. You can plan on a loss of 1 mpg for every mile over 55 mph.


    Merged.



    "My 2010 Prius 11 got 47 mpg on a 1300 mile trip to Erie,Pa from Dallas,Tx. Ran 75 to 85+ mph using cruise control as much as possible...My Honda used to get 23 mpg on the same trip at the same speeds. No [desire] to drive [at or] under the speed limit for better mileage. Actual mileage was 46 mpg figured manually."

    The above math means only one thing: you got 46 mpg. PA. Ohio, and Indiana speed limits are 70, so I doubt you did much 85 mph. Any P&G?
     
    #61 kenoarto, Nov 30, 2015
    Last edited by a moderator: Dec 1, 2015
  2. cyclopathic

    cyclopathic Senior Member

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    Indiana is 75
     
  3. kenoarto

    kenoarto Senior Member

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    No I-80 is still 70 mph. You must have found some of the rural Indiana freeways, but the interstate from New York to Illinois still 70 max with many areas that are slower, but none faster.
     
  4. cyclopathic

    cyclopathic Senior Member

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  5. kenoarto

    kenoarto Senior Member

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    104 isn't fast enough to get through Nebraska! Did see 85 in Texas! And then there are those coal burning nutz in Whyomnig...
     
  6. cyclopathic

    cyclopathic Senior Member

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    I will take Nebraska over Kansas anytime, day or night. If you find I-80 boring wait until you see I-70.
    I-40 isn't bad also I-90, but on I-90 winds are brutal much worse than say I-70 in west Kansas or I-40 in Mojave in CA. Nevada is also very boring and for roads being straight line are hard to drive on. For most part they didn't bother to profile so road follow dried lakebed outline and it is free range state I wouldn't want to be caught there after sunset. Plus there places with 165mi btw gas stations, so you can run dry if not careful.
     
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  7. lar.smith42

    lar.smith42 Active Member

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    "My 2010 Prius 11 got 47 mpg on a 1300 mile trip to Erie,Pa from Dallas,Tx. Ran 75 to 85+ mph using cruise control as much as possible...My Honda used to get 23 mpg on the same trip at the same speeds. No [desire] to drive [at or] under the speed limit for better mileage. Actual mileage was 46 mpg figured manually."

    The above math means only one thing: you got 46 mpg. PA. Ohio, and Indiana speed limits are 70, so I doubt you did much 85 mph. Any P&G?[/QUOTE]

    so I doubt you did much 85 mph - So your calling me a liar ! I normally drive 10 to 15 mph over on the interstate. I don't use p&g and air in tires is set to Toyota specs. I also run in normal mode.

    The above math means only one thing: you got 46 mpg - I don't understand your point here. That exactly what I said if you read the above Quote.

    If your ever close to here send me a mesg and I would be more that happy to take you for a ride and show you how I drive. That includes any body else that thinks I'm lying.
     
    #67 lar.smith42, Dec 1, 2015
    Last edited: Dec 1, 2015
  8. kenoarto

    kenoarto Senior Member

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    Isn't Kansas the same p
    so I doubt you did much 85 mph - So your calling me a liar ! I normally drive 10 to 15 mph over on the interstate. I don't use p&g and air in tires is set to Toyota specs. I also run in normal mode.

    The above math means only one thing: you got 46 mpg - I don't understand your point here. That exactly what I said if you read the above Quote.

    You can't say that you got 47 mpg in once sentence, but later say you got 46. Further, you are suggesting an average speed of 80mpg got you 46mpg. That would be set a very high new record here at PriusChat.
     
  9. cyclopathic

    cyclopathic Senior Member

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    Can we all get alone?

    We've driven 2010 Prius loaded with 4 people across the country and back (8600mi) and averaged 51MPG. The only time we saw 38MPG was going up 4-6% grade on I-40 in New Mexico, at ~80MPH.

    C is much worse, the only question is why? Aerodrag alone isn't enough to explain it.
     
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  10. lar.smith42

    lar.smith42 Active Member

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    What I'm saying is that the car said I was getting 47 and when I figured it out manually is was 46 mpg. I don't think that that is to hard to understand. When i go thru Ok, Il, In. (the northern route I usually average 47 to 48 mpg. when I go thru ark.,tn,Ky. (the southern route and mountainous rt) I usually get about 45 mpg.cyclopathic said:
    Can we all get alone?We can and I will kinda help it along. I get kinda tired of somebody arguing with me when I share some real word data or experience. I guess I must have a 1 in a million Prius. even my drivers seat is comfortable.So I guess I'm done with Prius Chat. Some of you have been real helpful but the rest really need to get a life.
     
  11. Adadrian

    Adadrian New Member

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    I get great city and suburb mpg as well. but highway is disappointing
     
  12. cyclopathic

    cyclopathic Senior Member

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    Found this posted by Bob:
    [​IMG]
     
  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Finally figured out the above esoterica:

    nhw11= gen 1 prius
    nhw20=gen 2 prius
    zvw30=gen3 prius

    Interesting that gen 1 and 2 seemed to maintain decent mpg more so, as speed climbs, while gen 3 has a more linear decline, per the others. Or were there just not enough data points??

    I tend to distill such info to a much simpler message: Want good mpg? Slow down.
     
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  14. Sean Nelson

    Sean Nelson Active Member

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    I suspect that the "knee" of the curve on the earlier Priuses may be due to the engine having to run in a different range for the highest speeds. The continuously variable transmission can only cover a certain range of gear ratios, so it may well be that on these models the engine has to run at higher RPMs outside of its most efficient band of operation when travelling above 65MPH.

    This may be the same reason why you're seeing a bigger drop in MPH than you expect at high speeds in the Prius C. Since it's specifically targeted for city use, the drive train is probably not optimized for those highest speeds and the car may have to operate in a less efficient mode to achieve them.
     
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  15. kenoarto

    kenoarto Senior Member

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    Gen III line shows 75mph mpg is 47. At 85 mpg is 40 or less? And this data is from Bob's expert driving.
     
  16. cyclopathic

    cyclopathic Senior Member

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    That was my thought. Perhaps we need Bob Wilson to comment on his creation?

    BTW I think the knee in on graph is due to data collection quantization, as car was tested at 66, 67, 68, etc, just at 55/65/75. The real line could be more of a curve.

    Irreguardless, to make C highway worthy you need aero improvements and better LRR tires, that way you could move speeds above 65mph into usable range.
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    Or just slow everyone down. Yeah, I know...
     
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  18. Sean Nelson

    Sean Nelson Active Member

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    Hey, hey - enough with those radical suggestions. :p
     
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  19. mrpinkie

    mrpinkie Junior Member

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    Thanks for the info, I was already noticing the difference temp makes in mpg. Getting confirmation from other drivers is a sanity check. I'm in the Raleigh area, and my commute is about to go down to 8 miles on surface streets in a few weeks so that will be nice.
     
  20. tnt4him

    tnt4him Junior Member

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    I don't think that is unusual. My 12 C3 did about 41mpg at 67mph on a 150 mile trip through the Columbia Gorge I84, up and down hills and wind resistance. I had 4 people with ECO on and cruise. I notice if I slowed to 55mph I would get back to 44mpg. I am always trying to figure out how to get some of these awesome ranges of 70 to 80 that some report. But I think the 40's are average.