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Mileage - odd situation

Discussion in 'Gen 2 Prius Fuel Economy' started by Blegate, May 3, 2006.

  1. Blegate

    Blegate Prius Gen III 2013

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    Hello all- I've been a prius owner for about 3 weeks now and I'm approaching the 1K mark. Recently I've noticed some odd mileage results from the MFD. When I first got the car the trip computer stated I was getting anywhere from 47 to 51 MPG on my daily commute (19 miles) which seemed fairly accurate. Since last Saturday things have changed. Yesterday it said I got 57.4 MPG and today it shot up to 61.5MPG. The only thing I've done since last Satruday is increase the pressure of the tires to 44/42. Originally the tires were at 40/33. I can't imagine this change increasing my mileage so drastically. I do primarly commute on the highway but where I live it's really a lot of stop and go/40 to 55 MPH type of highway traffic. About the last 2/3 miles of my commute my car is essentially in EV mode with little ICE being used.

    In addition I've noticed that if I don't drive with cruise then my mileage suffers more than it used to (mid to low 40's). With Cruise on the mileage indicator is giving me results as mentioned above. I'm currently in the middle of testing how many miles I can get on a full tank of combined driving. Once I get done I'll do the old total miles/gallons of gas calculation.

    I do not know. I thought I would share this current situation with everyone. I'm not too worried since the car is new still.
    Comments?

    (BTW I've read the EPA article on gas mileage, etc. for new owners)

    Brian
     
    #1 Blegate, May 3, 2006
  2. Betelgeuse

    Betelgeuse Active Member

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    <div class='quotetop'>QUOTE(PriusBrian @ May 3 2006, 01:05 PM) [snapback]249101[/snapback]</div>
    A Few thoughts:

    - Changing the tire pressure really helps; as you said, I don't think it can be the whole story, but it certainly helps.

    - Has there been a significant temperature change in WA in the last week or so? If it's gotten warmer, that could explain some of it.

    - Do they have "winter gas" and "summer gas" in the Pacific NW? In the NE, we have "summer gas," which tends to give better mileage than the "winter gas."

    - A significant factor may just be that you're learning to drive the car efficiently. There is a break-in period for the car after which it gets better mileage, but there's also a break-in period for the driver.

    EDITED to add: It should be said that the type of driving that you do (40 - 55 MPH) is EXACTLY the type of driving where the Prius really excells. Enjoy it! :)
     
    #2 Betelgeuse, May 3, 2006
  3. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    I took the liberty of plotting out the high temps for Vancouver from April 10 to May 3. There is a mild - though eratic - upward trend. SO it's possible that temperature has played a part in the improvement. Also, bumping those back tires from 33 to 40 is a huge improvement. I hvae one tire with a slow leak and I can tell when it drops to near 35 psi. I can't imagine the drag on rolling resistance with two tires at 33 psi.

    FInally, do not rule out that you are becoming a better driver. ;)
     
    #3 TonyPSchaefer, May 3, 2006
  4. j24816

    j24816 New Member

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    In addition I've noticed that if I don't drive with cruise then my mileage suffers more than it used to (mid to low 40's). With Cruise on the mileage indicator is giving me results as mentioned above.

    Congrats on your prius; like you I've had mine about a month.

    Initially MFD indicated milage in low 40's. I started using cruise and improved my milage somewhat (maybe mid 40's, don't really remember....this is all on 1st tank of gas). After studying the driving tips posted on Priuschat I cut use of the cruise, practiced technique and am now in low 50's overall. Commute (9 mi/30 minutes), not unusual to have MFD ~75 mpg (!) after 1st 5 minute bar which is always ~25MPG. And I'm still learning. (Overall milage suffers due to shorter trips on weekends ferrying kids from activity to activity)

    There is a lot of good info and a lot of good people on this site....make good use of it, and good luck!
     
    #4 j24816, May 3, 2006
  5. ghostofjk

    ghostofjk New Member

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    <div class='quotetop'>QUOTE(PriusBrian @ May 3 2006, 10:05 AM) [snapback]249101[/snapback]</div>
    Worried? About the MPG going up?

    I'm with the others: removing the imbalance in your tire pressure (how did they ever get set at 40/33?), higher temps and YOU improving your Prius driving skills. It's not at all uncommon, especially this time of year. Good for you!
     
    #5 ghostofjk, May 3, 2006
  6. hdrygas

    hdrygas New Member

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    <div class='quotetop'>QUOTE(Betelgeuse @ May 3 2006, 10:17 AM) [snapback]249111[/snapback]</div>
    Yep winter and summer gas. The old change over was in April but I think "W" changed the rules because I saw a jump in February this year?
     
    #6 hdrygas, May 3, 2006
  7. tomdeimos

    tomdeimos New Member

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    I've been seeing some mpg fluctuations from my fuel. I'm guessing it has to do with the ethanol switch and shortage. I got fuel at my regular station and immediately lost about 4 mpg. I measured over half a tank.
    Then I added some octane booster and mpg went back up to near normal for the second half of the tank.

    Next fill up I used another station and mpg remained normal.
     
    #7 tomdeimos, May 3, 2006
  8. hobbit

    hobbit Senior Member

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    Keep in mind that your mileage *average* will whip around pretty
    drastically just after you fill up, and then eventually settle down
    once the miles rack up and you get a damping factor.
    .
    _H*
     
    #8 hobbit, May 3, 2006
  9. Blegate

    Blegate Prius Gen III 2013

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    <div class='quotetop'>QUOTE(hobbit @ May 3 2006, 06:14 PM) [snapback]249371[/snapback]</div>
    Thanks for all of the replys. I think everything is fine and I'm just having "new owner" worries. Coming home today my MPG was at 51 which is really good.

    brian
     
    #9 Blegate, May 3, 2006
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