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Perfect conditions for optimum MPG?

Discussion in 'Gen 2 Prius Main Forum' started by MarthaW, Sep 25, 2008.

  1. MarthaW

    MarthaW New Member

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    My Prius isn't here yet but for those of you with the most experience, I was just wondering what the optimum conditions for getting the best MPG are. I read that Summer is better than Winter and continual driving is better than stop and go. Obviously, unloaded car rather than loaded down. Other than that, for a given trip, if you could drive any speed you wanted, what speed would give the best MPG? Any other variables that matter?
    Thanks. I'm just dreaming ahead to when mine arrives.
    Martha
     
  2. beckerman

    beckerman Junior Member

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    Straight downhill.
     
  3. nerfer

    nerfer A young senior member

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    70 degrees, roads at 35 mph, no stop signs (stop lights okay if you can slow down enough to roll thru on a green). Gently rolling hills, if you use pulse and glide, otherwise level.

    That's the external situation, then you can pump up the tires to 42/40 psi or better, use pulse-and-glide (moderately accelerate to 40, glide to 30 and repeat) and of course start with a warm engine.

    Kinda like what the 5 guys did in Pennsylvania in 2005 - they filled up a Prius tank as much as they could and drove under optimum conditions until they ran out of gas, and averaged 109.3 mpg over nearly 1400 miles. It was discussed at the time in this long thread. Toyota has a nice wrap-up of the results in their newsletter article.
     
  4. catgic

    catgic Mastr & Commandr Hybrid Guru

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  5. mwlowder

    mwlowder Junior Member

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    Around town driving in spring and fall gives best milage. The AC doesn't run much. Do a lot of coasting. Don't use cruise control, accelerate little when climbing a hill and coast (at any speed) going down. Give up the notion that a constant speed will give you the best milage.

    I'm consistently getting 54.2 mpg this time of year. (Fall in Iowa)
     
  6. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    I have found that I get better mileage with a fully-blocked grill at temperatures in the low 80s.
     
  7. skoh

    skoh New Member

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    Don't forget to use 0W-20 engine oil for better fuel economy & better cold start performance.
     
  8. ken1784

    ken1784 SuperMID designer

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    World record distance on a single tank for a Prius II - Japan - July 4 - Aug 16, 2006 - CleanMPG Forums
    If you would like to duplicate her 112 mpg result, please read the story and learn followings; :)

    - hotter weather is better, but don't turn on A/C even at 33C(91F).
    - don't drive in rain.
    - don't drive on highway, above 42 mph.
    - learn Pulse and Glide technique, pulse to 34 mph and glide to 19 mph.
    - inflate your tires, 45 psi front and 43 psi rear.
    - others on the story

    Ken@Japan
     
  9. PA Prius

    PA Prius Active Member

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    Following an oversize load, eg. house trailer, at less than posted speed limit. I got "caught" behind one of these a month or so ago. It is amazing how the Prius changes such driving situations from frustration to sheer bliss!

    PA P
     
  10. dbcassidy

    dbcassidy Toyota Hybrid Nation, 8 Million Strong

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    35 - 40 MPH, 75 degrees, flat road, 100% 87 octane gas (no ethanol), cruise control on, gives me 64.4 MPG.:D

    DBCassidy
     
  11. dwdean

    dwdean Member

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    Something that we're all kind of dancing around in these replies is that focusing on conditions is only part of the battle.

    I live in the land of Prius milk and honey (flat and warm), but I still know Prius drivers who don't get such good FE; two of them actually. The real key is in how you drive the car in whatever conditions you actually have.

    Don't get me wrong, that's not to say that conditions, both in your control (maintenance etc.) and out of it (weather, traffic, etc.), aren't important, they are, and there are definite incremental effects associated with such things. However, the biggest impact is who's in the driver's seat. Just look around at the FE numbers some have in their signatures; there's plenty of folk who live in places that have very challenging conditions but who also get truly impressive FE. "Conditions" didn't make those the numbers the drivers did.

    None of this is hard, just different, and it does take a little bit of an open mind and figuring out what works for you. Don't get frustrated if you don't get it right away, and do spend some time reading around here and other sites. There's good information out there.

    Enjoy your new ride when it arrives.
     
  12. JimN

    JimN Let the games begin!

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    Martha, IMO the car likes the outside temp in the high 60's to low 70's. There isn't much you can do about the terrain. If you have a choice of routes steady speed in the 40's-50's is better than stop & go.

    Blocking the grill helps by retaining engine heat (most noticeable after the 1st 5 minutes in cooler temps) and increasing tire pressure helps lower rolling resistance.

    With all that said, I believe I posted some good numbers (high 50's) driving around the speed limits on I-95/I-75/I-40 between Philadelphia & Winston-Salem, NC. Just drive & enjoy the car. The numbers will come in time.
     
  13. Silver 2008

    Silver 2008 Junior Member

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    First... I have a question? How do you guys block your grilles? I looked under the hood the other day and could not even get my hand in front of the radiator anywhere. Do you have to disassemble the front end or what?

    As for my tips... (in town)

    1. Accelerate to 4 MPH above the speed limit at a moderate pace. Do not baby it, but do not floor it.

    2. Back off the accelerator to the point where you just maintain the speed. Its OK to lose a MPH or two while finding this position.

    3. Cruise right there. If you are going down a slight hill, back off the throttle slightly until you are "gliding" meaning no power is applied and you are not using regenerative braking. If you start to pick up speed, back off slightly more to engage regenerative braking.

    4. Look far ahead to anticipate stops. When you see you will need to, begin "gliding" so you don't lose speed too quickly. When you get closer, let off the accelerator completely to engage regenerative braking. When you get a little closer, apply slight brakes. Try to stop in a long distance as the batteries absorb more of the braking energy this way. With practice you will learn how to maximize the distance you travel with the gas engine (ICE) off. Just try to find a balance between maximizing the coast and not being a burden to traffic :)

    5. Repeat.

    Mike
     
  14. JimboK

    JimboK One owner, low mileage

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    Simple, no disassembly required. (I just did mine tonight, in fact, in about 15 minutes.) Most of us use foam pipe insulation available from any home improvement store. Then we just push it into the fins of the grille. I use cable ties on the bottom to hold it. The top stays in place on its own with friction. Do a good search for "grille block" and you'll find detailed descriptions, with minor variations, and some with pics.
     
  15. JimN

    JimN Let the games begin!

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