Best way to get maximum MPG for long trips

Discussion in 'Gen 2 Prius Fuel Economy' started by pria, Aug 5, 2008.

  1. pria

    pria New Member

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    So I'm going on a road trip and wanted to know suggestions on how to get the best MPG. I know if i serach, I'll find a thread but I can't find one right now through all the mud:)

    Just want quick pointers like if I should do cruise control or go a certain mile.

    Its mostly highway so I should be constant speed ..If speed limit is 70..I'll probably be going 75. I heard 55mph is the best but there is no way I'm driving that slow on a highway.

    Any help would be greatly appreciated. Also how many MPG can I expect to get on a long roadtrip with 90% highway miles?

    Lastly, how many miles approximately does each bar represent on the gas meter? Right now I drove 100 miles and lost 1 bar:) Car is showing that I am avg 40mpg.


    Thanks
     
  2. Genoz World

    Genoz World ZEN-style living

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    hello pria,

    welcome to PC. anyways, there are MANY other people that know more than me, but there are certain things you can do.

    CONSUMPTION gauge - watch it on your peripherals! watch the yellow bar, and try to drive so it's the highest it can be. dont be afraid to use fuel, but dont "DRAG" your consumption on it's lowest point. accelerate, then lift off and try to keep the yellow bar as high as possible.

    you can set your CC, but if you feel it drag, lift it, go a bit slower and then accelerate on a decline. doing this, you should average 45+ on any highway.

    good luck, just my advice.
     
  3. JimboK

    JimboK One owner, low mileage

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    If you've made up your mind ahead of time that you will exceed the speed limit, then you might as well not ask the question. Speed costs; how fast do you want to go? Rhetorical question for now, but one you need to answer for yourself.

    For the Prius, fuel economy decreases pretty much linearly with speed above 40 MPH. I understand if your highways are busy, and I agree that to go 55 may be a safety issue. There are highways in my neck of the woods, however, that at times have traffic light enough to allow 55 MPH safely.

    Having said that, terrain will largely determine the most efficient method. On terrain that's flat or nearly so, cruise control is probably your best bet. On hilly terrain, CC is very aggressive in trying to maintain speed, and does so at the expense of optimal fuel economy by pushing engine RPM into inefficiently high ranges. See this for a (somewhat technical) discussion of an alternative technique for hills.
     
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    As a Project Manager, I'm acutely aware of the saying, "Time, Money, Quality; pick two." That is, if you want it fast and cheap your quality will suffer; want it cheap and high quality it'll take longer; want it fast and high-quality you'll pay through the nose.

    In this case: "Speed and Mileage; pick one." As Jimbo has said, you've apparently already picked speed. At a constant 70mph, I've averaged around 55mpg. I've attempted drafting behind semis, pulsing and gliding, cruise control, and a few other things but rarely do I get the mileage above much more than the high-50s.

    Before the trip, make sure your tires are properly inflated. I run 52f/50r which is higher than many feel comfortable. Properly inflated to you might mean exactly what Toyota recommends, what it written on the sidewall, or any psi you want. Just make sure you verify the pressure before the trip.

    Then you can also try some of the slower-driving techniques such as dropping a few mph heading uphill and regaining the momentum on the other side. Cruise control will not do this since it is keyed in on speed. Therefore, you will either have to drive without it or bump it up/down as needed.

    Outside of that, there's not a whole lot you can do other than put in some good music or an audio book and enjoy the drive and the knowledge that you still more than doubling the mileage of many other cars on the same road with you.
     
  5. Indy John

    Indy John Member

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    This last Saturday the wife and I drove down I-65 to Louisville, KY from Indianapolis. We weren't in a hurry so we settled in a few car lengths behind a semi who was doing 64 m.p.h. and reset the MPG display. Outside temp. was about 85, little or no wind, and our A/C was set comfortably cool at 72. As we pulled into our hotel garage 95 miles later, the average m.p.g. display said 61.8.

    Drafting semis was on an episode of Myth Busters. It works. I wasn't dangerously close IMO, but a little closer than a normal safe following distance would dictate. In my experience, similar speed and conditions without the semi would have resulted in mid-50s m.p.g.

    We returned home the next morning with an extra person, more luggage, and a need to get back. I set the cruise to 75 and the bars read 46 to 47 all the way home in "clean air" (no semis).

    FWIW
     
  6. catgic

    catgic Mastr & Commandr Hybrid Guru

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  7. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Perhaps you might gather some data to add to our knowledge. Break up the trip into 1.5-2.0 hr. segments and run each at a different cruise control speed and record the mileage and conditions for each segment. Bring the data back and we can compare it to:

    [​IMG]

    You'll notice we have a gap at 65 mph ....

    Bob Wilson
     
  8. Danny Hamilton

    Danny Hamilton Active Member

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    I'll add my "Welcome!" as well.

    Now seeing as you are new here, you might not be familliar with some of the acronyms, abbreviations, and specialized terms that are common at PriusChat. Some of our regulars forget that these aren't typically used in the average person's daily conversation.
    Scientific Wild A** Guess
    Miles Per Gallon - Fuel Economy
    "Dino" = Dinosaur as in motor oil distilled from crude oil pumped out of the ground instead of synthetic oil.
    10% Ethanol Reformulated Gasoline mixture.
    Multi-Function Display (that little computer screen in your car
    The touch screen "reset" button on the "Consumption" screen.
    Electronic Cruise Control
    Hmm, first time I've heard this term. Seems to indicate using cruise control, but turning it off for hills.
    Watching the "Energy" screen and pressing the accelerator such that the Internal Combustion Engine is both powering the wheels and recharging the battery (as indicated with the arrows on the screen).
    Toyota's Hybrid Synergy Drive drive-train as used in the Prius consisting of Internal Combustion Engine, 2 Electric Motors/Generators, and the wheels of the vehicle all connected together with a single planetary gear.
     
  9. Genoz World

    Genoz World ZEN-style living

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    WHOA!!!!!!!!!!! look at those graph's!

    we're not worthy. i thought of just giving opinions here, but my goodness. the tech guys come on and games over.

    good info people. now, if i can only figure out my HTC mogul.........................
     
  10. donee

    donee New Member

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    Hi All,

    The Graphs need updating to include SHM. After a few miles constant speed on the highway between 50 and 55, the SOC gets up to 62 %, and then one can feather the throttle to a very low RPM. At 50 mph, level, and no wind this is about 75 mpg. At 55 level and no wind the result is about 65 mpg. I commute to work at 53 mph, and about 70 mpg for the highway portion, after the SOC has come up.

    Of course uphill and head winds will shift the speeds, RPM and mileage around. Its more typical for me to average in the high 60's on the highway commute portion, consequently. Which is actually a challenge to keep up with , on secondary road commuting because of the variability of the light time, when one commutes across the grain (here in Chicagoland, everything is set up radially out from Chicago, and circumfretial routes are all screwed up).

    On local road driving, the SOC runs more like 50 to 55 % and one cannot get the car to stop charging the battery on the short constant speed portions of a "city" / suburban drive.
     
  11. catgic

    catgic Mastr & Commandr Hybrid Guru

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  12. bwilson4web

    bwilson4web BMW i3 and Model 3

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    <AHEM> The graphs are complete because they are reproducible. The "SHM" advocates need to plot their own data. As my drill instructor used to say,"A grain of observation out weights 10 pounds of <an alternative> any day."

    Bob Wilson
     
  13. davidhol

    davidhol New Member

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    I drove over 5,000 miles in three weeks last June (2008) and tried to keep it at 55 unless there was a lot of traffic and felt I was a hazard. We achieved an overall average of 53 mpg and were pleased that we could enjoy the scenery more than usual using the lower speed.

    We drove from Roseville, CA to Zion Park, Denver, CO, Bloomington, IN, Minneapolis, MN then back through the Black Hills, SD to Salt Lake and then home.

    I did get Pierre (pee-air) up to 85 for a few minutes over the salt flats West of Salt Lake City and was pleased with the handling and performance.

    So, my advice is to sit back, relax and enjoy the countryside and the great mileage.
     
  14. pria

    pria New Member

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    Thanks everyone for your suggestions. Some of you went ALL out! haha

    Well, I just drove 1000 miles in the Prius (rental) and didn't really worry too much about maximizing the MPG. Averaged around 41mpg which I feel okay with considering I was going 70-80mph (up to 9 mph over speed limit going with the flow of traffic).

    A few questions as this is a rental car:

    1.) How do you 'gather data'
    2.) I just discovered that you dont need to press the unlock button to open the car as long as you are in range and don't even need to put the key in the ignition. greatest feature ever! (not really a question just a comment)
    3.) What model do I have. This model has an aux in as well as a camera for reverse viewing. Is there a way to keep the camera on even when you are not in reverse? (I know it is an 08 prius)

    I had some more q's but forgot. thanks again for all the great info!

    lastly, I saw at least 10 prius' on the way up here:)
     
  15. catgic

    catgic Mastr & Commandr Hybrid Guru

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  16. N3FOL

    N3FOL Member

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    I try to avoid drafting behind an 18 wheeler. It is one of the best way to get a nice paint chip from flying rocks. :eek:
     
  17. N3FOL

    N3FOL Member

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    I drove my Prius on a nice 800 + mile run an stayed pretty much around 68 to 65 mph. My average mpg turned out to be 51 mpg.
     
  18. craigk

    craigk Member

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    Don't put on a rear bike carrier with 2 bicycles hanging out in the wind at 70mph! My usual 49-51 mpg highway dropped into the low 30's :)() on this past weekend's 500 mile highway road trip. I'm going to try to fit them inside the car next time!

    (I don't think anything else was wrong, when I traveled at under 50 mph my fuel use was normal)
     
  19. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Actually, it is very simple.

    On long trips, you will be on the highway. This is when Prius spend about 75% of the energy pushing through air. There is no way around it other than slow down.

    If that is not a choice for you, then second best choice is to drive in a group with other cars. This means drive behind other cars (or even better, large cars/trucks). Be sure to leave a safe distance in front. Do not travel alone in out open pushing through air by yourself. Think as if you are a bird on a mission of migration.

    Typing this up reminds me of a joke. I'll throw this it in here.....

    Why do birds fly south during winter?


    You probably say because it is warmer. The anwer is because it is too far to walk.
     
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