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    sipsip New Member

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    I noticed a drop on my mpg while driving with an open sunroof. does anyone have the same issue?
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    szgabor Active Member

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    Really ??? No kidding .....

    Of course you did ... you ruined the car cf ... in other words aerodynamic design ...

    Read up! At highway speed you are (in most instances) better off using AC than opening ANY windows including sunroof.....

    If it is not self evidenced just search this site there are many thread about this.
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    Paradox Prius Enthusiast / Moderator

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    Yep, you kill the aerodynamics with open windows and/or and open sun roof at highway speeds thus reducing mileage. It's nuts but I remember reading someone some time ago removed their side mirrors to improve mpg's. :rolleyes:

    Anyway, this will happen in any car so it's not really an 'issue'.
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    F8L Protecting Habitat & AG Lands

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    I'm going to have to disagree a little here. The sunroof will obviously hurt mpg when opened at highway speeds but the A/C can hurt even worse if the car is not precooled or if you are making a short trip. The A/C can cause a 10mpg drop for the first 10min or more. Driving with the windows down is not nearly as bad. So for short distance driving I would roll down the windows. For longer trips I would use the windows cracked "flow through" technique in temps below 90F. For long trips or temps well into the 100s you should just say to hell with mpg and turn on the A/C!
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    jabecker driver of Prii since 2005

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    Here in Portland, when the sun comes out I open the sunroof. Vitamin D trumps mpg.
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    xpcman Active Member

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    What's that 3 or 4 days a year?
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    jabecker driver of Prii since 2005

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    We count a good six or eight days of summer in July and August.

    September now... we don't tell "outsiders" about that. September remains a closely guarded secret.
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    ftl Researcher

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    "If summer falls on a weekend this year we'll have a barbecue"
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    szgabor Active Member

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    I feel for you... but really the sunroof puts sunhine on you ??? guess you are sitting in the back seat ???)
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    jabecker driver of Prii since 2005

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    It just depends on the direction you're driving and the angle of the sun. It was shining on me today. It felt nice.
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    xs650 Senior Member

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    Portland weather forecast system.

    1: If you can't see Mt Hood it's raining.
    2: If you can see Mt Hood it's going to rain.

    I still think it's one of the nicest cities in the US:)
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    jabecker driver of Prii since 2005

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    Why, thank you! I rather like it here.
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    NineScorpions Economy, Meet Style!!

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    you give me a good idea for a trial. It is so hot here...the A/C is always in the on position. But in the morning...I could probably window-it until the warm up cycle completes. Our low temp is mid 70s. Now time to try it.

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