Wind affect on MPG

Discussion in 'Gen 2 Prius Fuel Economy' started by srellim234, Mar 20, 2018.

  1. srellim234

    srellim234 Senior Member

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    This was just driven home once again. Two weekends ago the weather pattern was such that when my wife took the Prius to Vegas, about 460 miles round trip, she was blessed with crosswinds and headwinds both directions. She ran the cruise control all the way from here to there and back. End result? 38 mpg round trip.

    This weekend she had to make the same trip. This time it was similar temperatures but a bit of tailwind one way, almost no wind the other. Again, cruise control from here to there and back. End result? 50.5 mpg.

    Even taking into consideration the inconsistency of the fuel bladder it is still pretty apparent the that the wind has a large affect on the mpg. I know there are some very old threads about this but I figured the topic is worth reviving since we are picking up so many new owners of older generation Prii. If you are getting some strange mpg readings, don't forget to factor in the prevailing winds on longer stretches..
     
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  2. egg_salad

    egg_salad Active Member

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    Oh, I absolutely agree. Although I've never seen anything as low as 38mpg, the winds here in Vegas do have a definite impact. A month or so ago, I made a road trip to Laughlin, NV. On the way there, I got 58mpg. On the way back, I got 47. There were a lot of cross-winds.

    My theory is that the more aerodynamic a car is (in a forward direction) the more susceptible it is to cross-winds. My old 1g Scion xB got poor mpg on the highway, but didn't get much worse when it was windy.
     
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  3. MelonPrius

    MelonPrius Active Member

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    There have been some brutal wind in the Vegas area lately. I've had drives where it was a struggle cruising at normal highway speed due to a head wind, so I'd just look for a conga line of vehicles to draft behind.

    Cross winds make for a tiring drive, too. Sometimes I make a mental note to get my alignment checked, not realizing the wind is blowing me to one direction.
     
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  4. LEVE

    LEVE Member

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    I've seen 37 to 38 mpg when crossing the Cascade mountains with a headwind. The same occurs on the flat when I'm in the Columbia River Gorge. Wind takes a terrible toll on mpg.
     
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  5. dolj

    dolj Senior Member

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    Yup.
    From my observations, agreed. My theory is the cross-wind disrupts the aerodynamic flow over the car.
    I have had the opposite with tail winds in both directions. That makes for impressive MPGs.
     
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  6. jerrymildred

    jerrymildred Senior Member

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    I agree that cross winds seem to be even more of a drag than headwinds for the Prius. But headwinds are no treat. And, statistically, if you're going to have wind, 2/3 of the time it will be either head wind or cross wind, which really stinks.

    On our trip to Ohio in Nov/Dec, we had 20_ mph head wind as well as rain going both ways, plus a fully loaded car. It was a real struggle to manage 50 mpg. Had I just set the cruise and let it go as usual, it would probably have been under 40 mpg.

    Just once, I'd like to make a long drive with a tail wind.
     
  7. srellim234

    srellim234 Senior Member

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    I hope you get your wish soon. It's fun to be just cruising along for a few hundred miles, not doing anything special and looking down to see the mpg between 70 and 90 mpg. I've had that happen a couple of times. Unfortunately, they've all (except one time) involved major hill climbing or a return against the wind for the second half of the tank so when I filled up the mpg was back down.

    If I had to pick one place I dislike driving the most because of crosswinds it would be the I-40 through Oklahoma. I've driven through there maybe 20 times over the years and every single time it's been a fight with the steering wheel no matter what car I've been driving. I wonder if the wind ever stops there.

    Any places stand out for you that are consistently bad because of the crosswinds?
     
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  8. Sam Spade

    Sam Spade Senior Member

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    You didn't mention speed.
    That has a huge impact on fuel consumption.......because you are bucking a stronger "wind" the faster you go.
    And it always is a headwind. ;)
     
  9. jerrymildred

    jerrymildred Senior Member

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    Yup. Nebraska and I-80. I used to go back & forth between Iowa and Colorado quite a bit. I remember one time on the motorcycle that was kinda scary. Leaning to the right at about a 45° angle as I went west and having to be super-careful as I passed semis to not get sucked under the wheels when they suddenly blocked the wind or blown off into the median when I finished the pass.

    Worse yet is the chinook winds in Colorado. My wife and I actually got blown over one night on the bike. Thankfully, we had just stopped because it was so bad. Those are not consistent, but they are pretty frequent.
     
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  10. srellim234

    srellim234 Senior Member

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    Yeah, those winds in Colorado are tough but inconsistent. Like the Santa Ana winds we get here. I live about 2 miles west of the wind tunnel known as the Cajon Pass. Multiple times a year the wind will be maybe 5 mph here but gusting 60+ mph just a few miles away. Needless to say, I avoid driving east when those winds are blowing.

    I've only driven that stretch of I-80 once and it wasn't bad. We'll be driving it coming home from our trip this summer, though, so thanks for the warning..
     
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  11. Zythryn

    Zythryn Senior Member

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    Well, not always. If you are doing 90 though, and still have a tailwind, you should either go faster, or find a good tornado/hurricane shelter :eek:
     
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  12. srellim234

    srellim234 Senior Member

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    That thought actually crossed my mind. With jerrymildred being in Florida, maybe if the hurricane is approaching at the right angle and he times the evacuation correctly he could get a massive tailwind all the way to Georgia. :LOL:;)
     
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  13. jerrymildred

    jerrymildred Senior Member

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    We hit some really nasty winds out your way a few years ago driving a Honda Oddessy. We were going west headed up into the mountains on I-8. Head winds were something like 80 mph according to the radio. Came around a bend to find a tractor-trailer rig laying on its side spanning all three lanes. The state patrol had just arrived and we managed to sneak by on the shoulder a few seconds before the closed the road. BTW, the Oddessy makes really weird noises driving at interstate speeds into an 80 mph wind. :eek:
     
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