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Poor MPG From Prius. Worse From Porsche

Discussion in 'Gen 2 Prius Fuel Economy' started by jyl, Dec 16, 2006.

  1. jyl

    jyl New Member

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    Our 2007 #5 now has 800 miles. It's been chilly since we bought the car (25F lows to 40F highs) and our driving has been all city, cold start, short trips. Longest trip is 7 miles home to kids' school and 7 miles back. The fuel economy has been around 36 mpg. It has improved a bit since the first tankful, maybe 2 mpg.

    So, I'm not thrilled with the fuel mileage, but given the brand new car, cold temps, short-ish trips, and winter gas, I'm not worrying about it yet.

    The reason I posted this is because I just checked the mileage on our other car, my 1989 Porsche 911. This car usually gets around 25 mpg in mixed city/highway in summer. It's been driven in the same conditions as the Prius, a bit worse actually, typical day is cold start, then 4 miles from home to work, then sit 12 hours and return.

    The Porsche's most recent tank delivered just 13 mpg.

    I guess I don't feel so bad about the Prius' mileage.
     
    #1 jyl, Dec 16, 2006
  2. efusco

    efusco Moderator Emeritus
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    Good way to put it into perspective isn't it!

    You're not through break-in (both the car and your own break-in with it), you've figured out the cold weather issue. You didn't mention tire pressure, but I'd definately check those and pump them up to at least 40f/38r (I use 42f/40r, some go 2psi higher in both).

    You'll be back, in the Spring, thrilled w/ your mileage.
     
    #2 efusco, Dec 16, 2006
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    <div class='quotetop'>QUOTE(John L. @ Dec 16 2006, 09:12 AM) [snapback]363122[/snapback]</div>
    Indeed. Most people notice their Prius mileage but tend to forget their previous vehicle (or other vehicles in the garage) undergo the same effect during winter.
     
    #3 Tideland Prius, Dec 16, 2006
  4. Wetnabber

    Wetnabber New Member

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    <div class='quotetop'>QUOTE(John L. @ Dec 16 2006, 01:12 PM) [snapback]363122[/snapback]</div>
    I have a question about Prius mileage. I am thinking about taking my 06 Prius to Ziebart and having it undercoated to cut down on road noise. First would this mess up the Toyota warranties, and second, will the weight of the undercoating (I think Zeibart uses a heavy coat) lower my gas mileage?
     
    #4 Wetnabber, Dec 16, 2006
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    I can't say about the first part (although I don't see how it can affect the warranty) but it will lower your gas mileage since it adds weight.
     
    #5 Tideland Prius, Dec 16, 2006
  6. cwerdna

    cwerdna Senior Member

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    The short trips and cold weather are really contributing to the low mileage.

    In addition, since the it's so cold out, I suspect you're using the heater, which unfortunately tends to cause the ICE to stay on or cycle on more. I've observed this many times myself where I'd just started up cold (after 9 hours), drove a very short distance (<1/ 2 mile) w/the heater on and then stopped a a traffic light w/the ICE running. It continues to run and then stops the instant I press OFF in the climate control screen.

    Luckily, I don't have to go much further before I get on the freeway, so as I enter the freeway, I turn the heater/fan back on since I know the ICE will HAVE to run since I'll be going well above 42 mph.

    FWIW, when Consumer Reports tested the Prius in their driving cycle, they got 35 city/50 highway, 44 overall. See http://www.consumerreports.org/cro/cars/bu...s-206/index.htm.
     
    #6 cwerdna, Dec 17, 2006
  7. JimN

    JimN Let the games begin!

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    <div class='quotetop'>QUOTE(Wetnabber @ Dec 16 2006, 07:01 PM) [snapback]363237[/snapback]</div>
    I believe the concensus for all cars is that undercoating is not necessary and could be detrimental if it blocks a drain hole.

    On asphalt I don't notice any road noise but in OH and IN on concrete she wailed like a banshee. I don't know if it was the tires or lack of soundproofing.
     
    #7 JimN, Dec 17, 2006
  8. Joe Bernard

    Joe Bernard New Member

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    If you're doing those 7 mile trips on a cold engine, it will stay on longer to heat it up. I let my car warm up in the driveway until the gas engine shuts down, then I hit the road. Hopefully that helps. You really should be getting a little better mileage. 40 mpg at least in town. Of course, a broken in car and warmer weather will definitely help.
     
    #8 Joe Bernard, Dec 17, 2006
  9. jyl

    jyl New Member

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    Using the heater (climate control set on 70F and auto) and also the electric seat heaters. I suspect the engine isn't warmed up for 1/2 the drive.

    I'm not worried about the mileage. Realizing that the mileage of the 911 is barely 1/2 its "normal" mpg has made me understand how cold weather and short trips affect mpg.

    Anyway, the Prius is replacing a 1995 Range Rover which gets 15 mpg in the best of times. I suspect the Rangie was getting well under 10 mpg in these conditions. My wife was filling the Rangie's tank every 5 days, at $60 a pop. We estimate the Prius is saving us nearly $300/month in gas.
     
    #9 jyl, Dec 18, 2006
  10. qbee42

    qbee42 My other car is a boat

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    <div class='quotetop'>QUOTE(Slow & Green @ Dec 18 2006, 12:44 AM) [snapback]363599[/snapback]</div>
    It doesn't. The best way to warm up a Prius, other than a block heater, is to drive it. The engine is going to run either way, so you might as well use the power directly to move down the road.

    Tom
     
    #10 qbee42, Dec 18, 2006
  11. jyl

    jyl New Member

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    Just reviving this threat to note that, with summer weather and 8000 miles on the Prius, we're now getting around 45 MPG. Still all city, cold start, short trips.
     
    #11 jyl, Jul 18, 2007
  12. MarkMN

    MarkMN New Member

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    <div class='quotetop'>QUOTE(John L. @ Jul 18 2007, 04:50 PM) [snapback]481233[/snapback]</div>
    That is typical. In my short trips I get about 47 nowadays, but last winter when you got 36 mpg, I was getting 42 in colder weather (no block heater or anything). On 55mph rural highways though, I get about 56 mpg without hypermiling and driving speed limit.
     
    #12 MarkMN, Jul 18, 2007
  13. JimN

    JimN Let the games begin!

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    John & Mark, have you considered blocking the upper grill & increasing the tp?
     
    #13 JimN, Jul 18, 2007
  14. jyl

    jyl New Member

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    <div class='quotetop'>QUOTE(JimN @ Jul 18 2007, 05:05 PM) [snapback]481302[/snapback]</div>
    Car is mostly driven by wife and it is getting hot here - 100F some days - so don't want to block grille, she'd probably overheat it. The AC is running much of the time. Am already running 42 psi all around.
     
    #14 jyl, Jul 24, 2007
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