1. Attachments are working again! Check out this thread for more details and to report any other bugs.

25 MPG on Long Trip from TX

Discussion in 'Gen 2 Prius Fuel Economy' started by wallymw, Mar 8, 2009.

  1. wallymw

    wallymw Happy Prius Owner in Mpls

    Joined:
    Mar 8, 2009
    10
    0
    0
    Location:
    Minneapolis
    Vehicle:
    2004 Prius
    I just came back from five week trip to Austin, Texas (Mpls to Austin).

    I was hauling two pets, another passenger, two bikes (on back rack) and luggage. I was SHOCKED to see how drastic my milelage changed throughout the trip. It varied by tank anywhere from 40 MPGs, down to 25 MPG. It did seem quite windy, but couldn't believe the MPG could drop this low!

    I was doing freeway driving and also noticed that I never got any recharge icons on the display screen.

    When I was driving in Austin, my average MPG was nearly 50mpg throughout the hills in Austin, so it didn't seem to be a hill thing. Wondering if it was either freeway driving (no stopping, starting), wind or hauling load.

    Any ideas?
    Thanks!
     
    #1 wallymw, Mar 8, 2009
  2. EJFB1029

    EJFB1029 New Member

    Joined:
    Jan 16, 2008
    4,726
    206
    0
    Location:
    Corpus Christi, Republic of Texas
    Vehicle:
    2008 Prius
    Wind, I had the same problem coming up from Brownsville to Corpus Christi, wind cut down mileage really bad.
     
    #2 EJFB1029, Mar 8, 2009
  3. firepa63

    firepa63 Former Prius Owner

    Joined:
    Jul 23, 2005
    1,761
    208
    0
    Vehicle:
    Other Hybrid
    Model:
    N/A
    How was your tire pressure?
     
    #3 firepa63, Mar 8, 2009
  4. ksstathead

    ksstathead Active Member

    Joined:
    May 1, 2007
    1,244
    243
    0
    Location:
    Kansas
    Vehicle:
    2010 Prius
    Model:
    III
    The bikes increased your Cd and your frontal surface area. At freeway speeds, that increased aero drag is very significant, making the engine work harder. You didn't mention what speeds you ran, but you should have seen impg vary with speed...
     
    #4 ksstathead, Mar 8, 2009
  5. donee

    donee New Member

    Joined:
    Aug 15, 2005
    2,956
    197
    0
    Location:
    Chicagoland
    Vehicle:
    2010 Prius
    Model:
    III
    120 mph airspeed, with two bycycles on the roof will do that...
     
    #5 donee, Mar 8, 2009
  6. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    wallymw,

    If you took the bikes off while driving in Austin, getting the "regular,"
    50 MPG is a clear indication of the massive negative effect of the bikes
    in the rack on your MPGs. I'm not so sure of increased frontal area,
    but the airflow in the supercritical area at the back of the car was
    most likely all screwed up = increased drag = low MPGs..

    It comes with the territory whether its a bike rack, roof rack, windows
    open, whatever. The Prius' FE is very sensitive to increased Cd at
    speeds probably as low as 20 MPH.
     
    #6 Rokeby, Mar 8, 2009
  7. CharlesJ

    CharlesJ Member

    Joined:
    Dec 13, 2008
    467
    29
    38
    Location:
    Monterey
    Vehicle:
    2008 Prius

    Not long ago, Consumer Reports had a small segment talking about cargo on top, tire pressure, etc. That cargo on top decreased MPG by about 10, if I remember correctly. So, depending on your cargo on top, it could be even more. Just having the hardware on top can have a measured effect.
     
    #7 CharlesJ, Mar 10, 2009
  8. JimN

    JimN Let the games begin!

    Joined:
    Nov 26, 2006
    7,028
    1,116
    0
    Location:
    South Jersey
    Vehicle:
    2010 Prius
    Model:
    V
    Regen is from braking. The ICE ran to charge the battery as needed.
     
    #8 JimN, Mar 10, 2009
(You must log in or sign up to post here.)