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MPG at set MPH

Discussion in 'Gen 2 Prius Fuel Economy' started by ghirl, Nov 25, 2005.

  1. ghirl

    ghirl Junior Member

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    Does anyone have any data on MPG after driving the prius at 55 mph for at least one hour. And then 65 mph for at least one hour. And 70/75 mph for at least one hour. I am currious to see some data on how the speed correlates with mpg over a 1 hour drive at the above speeds. I have my name on a wait list for a prius. I will be doing mostly highway driving for a daily roundtrip commute of 110 miles. The speed is usually around 65/70 mph if you want to keep up with the other drivers.

    I test drove the 06 Honda Civic Hybrid last weekend. I prefer the features of the Prius. But I am wondering if the HCH might get better mileage on the highway. Someone posted on the greenhybrid site that they did the above test with the HCH and received the following results:
    60mph+= 51.7 mpg
    70mph=44.9 mpg
    80mph=43.4mpg
    link to thread: http://www.greenhybrid.com/discuss/cruise-...ml?page=2&pp=10

    Please post your thoughts. Thanks.
     
    #1 ghirl, Nov 25, 2005
  2. Wayne

    Wayne Active Member

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    Well, I didn't test for 1 full hour, that would have been too big a commitment of time, and it would have been hard to hold all the environmental conditions (not to mention speed) constant for that long. However, I did do a careful test, and the data points held up pretty well when charted, so I am confident in the results (except at 80 MPH).

    I got a little better results than the HCH at speeds below 80, but my 80 MPH test was interrupted:

    60mph = 59 mpg* calculated, tested at 55 and 65
    70mph = 50 mpg
    80mph = 38-41mpg* my test got glitched, so not sure of exact reading

    You can see the full test and methodology here:

    http://priuschat.com/index.php?showtopic=11741&hl=
     
    #2 Wayne, Nov 25, 2005
  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I have an 03 Prius and performed (and continue to perform) these tests:

    http://hiwaay.net/~bzwilson/prius/

    Most of my data comes from 70 degree, Indian Summer days. We're now into Fall and I too have noticed a fall off in MPG . . . but that is just a new puzzle.

    Bob Wilson
     
    #3 bwilson4web, Nov 25, 2005
  4. ghirl

    ghirl Junior Member

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    Wayne,
    Thanks for the data. Just what I was looking for. Looks like your data beats the HCH at 60 and 70 mph but not at 80 mph.
     
    #4 ghirl, Nov 25, 2005
  5. Wayne

    Wayne Active Member

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    If you really care about fuel efficiency, you won't be driving 80... :p

    Besides, if you understand the vast number if variables involved, we really didn't score differently than one another. Especially since my data (at least) got glitched. I say at least, because they show an almost 7 MPG difference when going between 60 and 70, and only a 1.5 MPG difference when going between 70 and 80. I would think 70 to 80 would have been greater than or equal to 7 MPG...
     
    #5 Wayne, Nov 25, 2005
  6. efusco

    efusco Moderator Emeritus
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    There are far too many variables to make any kind of realistic comparison. Even a mild head-wind, or worse a cross-wind, will dramatically affect mileage. Ambient air temp will as well. Plus humidity, elevation, road conditions, AC settings, etc.

    There's a program about to be released commercially called THS II Simulator created by Wayne Brown that you can plug in all the possible variables and derive a good estimate of the MPG. If you gave me all the variables I mentioned above for your test-drive of the HCH I could plug that into my PDA and give you the equivalent Prius mileage. I'm quite confident Prius would, in reality, do better than the Civic at all speeds.
     
    #6 efusco, Nov 25, 2005
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