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Much bigger drop in MPG than expected

Discussion in 'Prius c Fuel Economy' started by MunkusMPG, Feb 28, 2014.

  1. MunkusMPG

    MunkusMPG New Member

    Joined:
    Feb 4, 2014
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    Vehicle:
    2013 Prius c
    Model:
    Two
    Hi all! I had to fill my car for the second time two days ago and was shocked when it took as much gas as the first time but had a dramatic drop in mpg (First tank took 7 gallons for an average of 56.1 mpg. The second took 7 gallons for an average of 39.7 mpg) The dealer sold the car with a "full" tank. I know that most dealers don't really fill the tank all the way so that would mean that my first fill up would require more gas than my second if I drove the same amount of miles. So I should see an improvement in mpg on the second fill up. The first half of my driving with the initial tank of gas was done in mild sunny weather and the second half was done in colder weather.

    The second tank of gas was used in all rainy cold weather with more short trips than the first tank. I expected a drop in mpg but thought that my improved driving technique would make up for those negative factors. (I had been getting some great results from using the driving tips) I also know that many have warned that the car displayed mpg in usually higher than actual mpg. But the first fill up was spot on and the second was displaying 48 mpg. That's a discrepancy of 8.3 mpg from the car display and a drop of 16.4 mpg from measured results of the first tank. All because of some rain and cold....????(n)

    P.S. How do I link my fuelly info?[​IMG]
     
    #1 MunkusMPG, Feb 28, 2014
  2. jdk2

    jdk2 Active Member

    Joined:
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    Location:
    Raleigh, NC
    Vehicle:
    2013 Prius Plug-in
    Model:
    Plug-in Advanced
    Here's the instructions for adding a fuelly signature: FAQ: How do I use a Fuelly forum signature/badge? | Fuelly

    Just add the code to your forum signature. You might want to add your location to your details too.

    The reduction in fuel economy could very well be weather related. As spring gets closer and temps rise, your fuel economy should go up accordingly. In addition, you'll need a couple more fillups to average it out. Also, check you tire pressure.
     
    #2 jdk2, Feb 28, 2014
  3. Bingee

    Bingee Member

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    May 28, 2013
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    Location:
    Michigan
    Vehicle:
    2012 Prius
    Model:
    Two
    If you live in a wintery state ,,, grill block ... Tire pressure 42/40 front/ rear
     
    #3 Bingee, Feb 28, 2014
    PriusGuy32 likes this.
  4. bisco

    bisco cookie crumbler

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    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    and the two tanks combined equal about 48 mpg which is a more accurate reflection.(y)
     
    #4 bisco, Feb 28, 2014
  5. AEROENGR

    AEROENGR Junior Member

    Joined:
    Apr 16, 2011
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    Location:
    Connecticut
    Vehicle:
    2011 Prius
    Model:
    Two
    Just wanted to provide an example of how Winter temperatures and driving conditions have affected my fuel mileage. I bought my Prius C last July and averaged between 60 and 65 mpg during the Summer. In September I began tracking my daily fuel mileage (see attached chart) which consists mostly of a ten mile trip to and from work. The trip is 5.5 miles of suburban driving and 4.5 miles on the Merit Parkway, which I drive at about 50 mph. It takes about 24 minutes each way. As we all know, temperatures in Connecticut this Winter have been well below normal. During September, I averaged about 64.5 mpg (as shown on the MFD) on the drive to/from work. During January, it dropped to 48.5 mpg, and in February, it was 49.9 mpg. As cold as it may be, I only use the heater when the engine is running full time on the Parkway. I think a conventional gasoline-powered car would have gotten less than half the mileage of the Prius C under these conditions. By the way, I'm running on the OEM tires and have been operating frequently on snow covered roads without any problem.
     

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    #5 AEROENGR, Feb 28, 2014
  6. GrumpyCabbie

    GrumpyCabbie Senior Member

    Joined:
    Dec 14, 2009
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    Location:
    North Yorkshire, UK
    Vehicle:
    2010 Prius
    Model:
    III
    Do you keep your car clean? I've heard if you wash and wax it regularly it will glide through the air easier and improve your mpg's :ROFLMAO:
     
    #6 GrumpyCabbie, Mar 1, 2014
  7. ztanos

    ztanos All-around Geek!

    Joined:
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    Location:
    Cumming, Georgia
    Vehicle:
    2012 Prius c
    Model:
    Four
    Nah, mythbusters did an episode where they added mud to a car in a dimple pattern and got better gas mileage from it. Anybody with hail damage concur? :LOL:
     
    #7 ztanos, Mar 4, 2014
    GrumpyCabbie likes this.
  8. NewYorkan

    NewYorkan Junior Member

    Joined:
    Jan 27, 2014
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    Vehicle:
    2013 Prius c
    Model:
    Four
    You did pretty good for 10 miles commute. My commute is 14.4 miles over Tapan Zee. My car don't warm up until about half way. I got only 25mpg for first half. The other half trip bring my average up to 47mpg, but only if traffic on I87. Last 2 days really cold and less traffic. I barely make 42 mpg. I was crawling in my company parking lot in EV mode to make that number. lol. If my trip is 10 miles like yours, I can't see my C will be over 40mpg.
     
    #8 NewYorkan, Mar 4, 2014
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