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    FirstFlight Member

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    For some reason, I was late everywhere this weekend. This led me to go between 70-80 MPH for a total of 330 miles. My MFD stated 50.3 MPG.

    Here is the strange part. When I try to pulse and glide at 55-60MPH, I typically get 54 MPG.

    It seems like there is very little difference between driving fast and aggressive and pulse and glide in my Prius.

    Has anyone else ever seen these results?
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    macmaster05 Senor Member

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    I know what you're talking about but there is a difference. Think about it, your MFD may have shown you gliding at 80mph, but how did you get there? It took more gas to get up to that speed and that's why you got 50.3 MPG, which is probably even lower when you calculate it at the pump.

    One thing to remember is "gas mileage usually decreases rapidly at speeds above 60 mph. You can assume that each 5 mph you drive over 60 mph is like paying an additional $0.24 per gallon for gas.1"

    1 Toyota dealership email, April 17, 2011.
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    FirstFlight Member

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    Didn't Texas just up their speed limit in some areas to 85 MPH. So if it was 65, they're going to pay an extra 96 cents per gallon, so to speak, just by going the speed limit?
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    macmaster05 Senor Member

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    I dont know. It's monday.
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    stevemcelroy Active Member

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    I'm jealous of the OP - I need to baby it and drive the speed limit to hit mid 50's - if I drive fast I'm luck to get 40.
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    sipnfuel New Member

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    It depends. If you went up a slight uphill that puts you out of the sweet zone at slower speeds anyways, the difference in mpg is minimal.

    On the downhill portion of my commute, I can get 66 mpg by going "slower" (keeping top speed at 65-70 mph). If I drive 70-80 mph in the fast lane, I only get 50 mpg. This is because the downhill portion brings me into the sweet spot. The reverse is not true in the other direction, the difference will be 48 (fast) vs 54 (slow).
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    Mark57 Active Member

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    Both Texas and Kansas are discussing it. I know I-10 down by Fort Stockton is 80 mph. The article says it's two highways in West Texas. I don't know which ones in Kansas.

    Texas lawmakers consider 85-mph speed limit - USATODAY.com

    I remember the days of 55 mph nation wide. I defined eternity as driving 55 mph across Texas. ;)
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    FirstFlight Member

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    This is what I don't understand. I can disregard any specific driving habits to conserve fuel and the lowest I get is 50 MPG. However, some people do all they can to conserve fuel and they don't even get 50 MPG.
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    Mark57 Active Member

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    I used to get PC trouble calls and you'd ask the user what they did or what changed and they'd swear nothing. Upon digging further, you'd find all kinds of things that "just happened" but not by that user of course.

    There are too many of us that can get good and better results given a similar playing field of temperature and terrain to assume the car is in error or incapable of getting good results. That has to leave a high percentage operator factors like a misunderstanding or poor implementation of good mpg techiques. It's hard to know what's really going on without riding with someone. I think the incident of low mpg due to mechanical issues is pretty low.

    Feel good that you're on the high side and not the low side.;)
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    ystasino Active Member

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    Well temperature (no A/C) traffic (less is better) terrain (as flat as possible) will impact the overall effect.

    I'm pretty sure that the actual 75 mph unobstructed mph in flat terrain segments give about 46-48 mpg with cruise control. I'm guessing that your extra efficiency is related to the way you slowed down to join regular traffic and then to arrive home. Also bear in mind that single measurements are suspect to error.

    Having said that it is possible to drive between 65-70 mph and get ~60 mpg in ideal conditions, particularly terrain. If you care to know how, there's a similarly titled thread in the first page of this FE forum now, but you need extra instrumentation (scangauge II) to help you control the engine power output efficiently.
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    kiel.martin77 New Member

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    Good forum and great information thanks for posting it
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    GrumpyCabbie Senior Member

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    70-80 mph for 300 miles makes you a mad man?

    Heck I must be a complete nutter - though incase any UK police are reading this I never go above 70 mph, this being the legal limit :D
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    priushippie New Member

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    I drive at or below the speed limit because I do not want a ticket to negate any $ I have saved with the Prius. I have gone over 100 mph twice but only for test purposes or I was angry at a tailgating gas hog pickup truck driven by a dumb hillbilly.

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