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My first tank (so far) MPG & ramblings.

Discussion in 'Gen 3 Prius Fuel Economy' started by Brett., Mar 22, 2012.

  1. Brett.

    Brett. Junior Member

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    [​IMG]

    Sorry if this post is long. Cliffs Notes: (For those who like instant gratification.) I love my car, I'm averaging 10mpg over what it is even rated to get under the driving conditions I experience and I wish I had purchased this car sooner.

    For those bored enough to read:

    I'm still working on my first tank of gas in my 11' Prius, but I'm close enough that I thought I might share some things I observed, and perhaps ask some things as well on driving techniques. I probably wont need gas for another week or more still and I'll be driving even less now that my current GF decided it's a good time to cheat. :rolleyes: OH well, anyway.

    Most of this tank so far my avg has been about 57.5-58.0 but after today I went for a drive down a stretch of road that didn't require me to use the ICE but for only a few hill climbs as to not lose all my inertia.

    First thing I wanna say is that when I bought the Prius, I anticipating getting around 48 mpg as I do not drive in city condition ever really. Where I live is all hills and 40-50 mph zones. Racking up this kinda mileage on the same tank of gas I bought the car with, and seeing the instant mpg figure steady 10mpg above what the car is rated to get in these conditions has me glad I traded already.

    There was a poster hanging behind the salesman for my very car, blue Prius and behind it in large characters it said "50" for mpg. I asked if the car could really get 50mpg, and the salesman said "It's possible, depends how you drive." I was also told that the car may get slightly better mileage after it's broken in for 10k miles or so. I don't know if there is any truth to the second part or not?

    Last but not least I have been accelerating to the highest speed I can without the ICE (when nobody is behind me) and I've been utilizing the glide technique for what it's worth on this car, not so much the pulse though. I just keep looking at the HSI display and backing off the accelerator pedal until I maintain speed with as little input as possible.

    I did wonder, is it more efficient to accelerate down hills to climb the next grade, or is it just as well to glide down picking up a little speed and using as little ICE as possible to climb the next?

    Tha'ts all for now, thanks for reading if you aren't asleep yet!
     
  2. F8L

    F8L Protecting Habitat & AG Lands

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    Very nice results. It just goes to show that hills are not so bad if you know how to tackle them. As for the GF, move on to better things bro. There are plenty more out there. :)
     
  3. ngc4565

    ngc4565 Member

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    Welcome to the club Brett. You are achieving excellent mileage for your first tank, but keep in mind that what you see on the display tends to be a little higher than reality. Nevertheless, you must be exceeding 50 MPG. FWIIW, or first tank on a Gen III Prius struggled to reach 46 MPG, so you are doing really, REALLY well.

    As a matter of curiosity, which OEM tires were supplied with your vehicle?
     
  4. Brett.

    Brett. Junior Member

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    I'll go look.....

    (time lapse)

    As a side note, my car was already filled once and driven a few hundred miles before I owned it, it was a leftover 2011 so people test drove it no doubt.

    (time lapse)

    Yokohama Avid S33 tires

    Once I fill the tank, I'll do a manual calculation of the mileage and report back in this thread. The guy I met with a Prius II locally said he gets 44mpg, and he didn't believe me that I was getting any more than 50, I'm anxious to find out how many gallons it takes to fill it.

    How big is our tank? 10.9 or 11.9?
     
  5. cnbmis

    cnbmis Junior Member

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    Officially 11.9g tank on the 2010, I think same for 2011. My max fill 11.77g.

    Kudos on your great results, especially first tank. It will be interesting to see what your calc vs. HSI difference is (mine runs between 4-7% optimistic), and how your vehicle evolves through break-in. Nice to see you getting that mpg with a reasonably high average speed, too.

    I only hit upper 50mpg (HSI) in the summer, but my primary route is a 65 mph road for 15+ miles right outside my door. I try to stay with traffic flow, so have to work on performance when I'm on secondary roads.

    Even with the hills, if your primary speed limits are 40-50 that seems to be the sweet spot for how this car was designed.

    Chris
     
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  6. p00kienrayray

    p00kienrayray Active Member

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    Most of these Prius owners that can't achieve 50 mpg don't understand that they have to adjust their driving styles. They think just bc its a hybrid, you can just mash on the gas pedal and still get 50+ mpg.

    I'm sure you would get at least 55 mpg. I just filled up for the first time last night. Indicator said 58 mpg, but I got 55.4 mpg calculated.
     
  7. Brett.

    Brett. Junior Member

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    It's kinda misleading that the HSI gauge reads so high because that's a rather large error, I am (dare i say) anxiously awaiting my trip to the gas station.. I just noticed the price of fuel has gone up like 20 cents since last time I filled up! I'm more glad I bought this car every day.
     
  8. ChipL

    ChipL Active Member

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    Good to know, thought the tank was more like 10.5 gallons on the Gen III. So was a little startled last night when I took 9.9 gallons on my last fill up with the blinking going on for about 20 extra miles when it first came on.
     
  9. Brett.

    Brett. Junior Member

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    Your low fuel light came on with more than a gallon and a half left? That's good to know
     
  10. Brett.

    Brett. Junior Member

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    Ok, well I just went out for a night drive and remembered reading somebody say "Don't find out how far the Prius will go, just fill it up when it's getting low."

    So, with 2 bars left on the gauge, and the "how far I can go" estimate reading 69 miles, I filled the tank and this is what I got for my first tank:

    [​IMG]

    I went 507.3 miles, and the car took 8.93 gallons of fuel.

    HSI = 58.8
    Actual = 56.8

    HSI was reading 2mpg higher.

    I'm sure the next tank will be a bit less since the body shop will have my car for a few days and then I'll only have short trips to work these days. I'll have to compare it next time. All in all, I'm happy with the results. Makes me want more.
     
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  11. pakitt

    pakitt Senior Member

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    Great first tank!

    Regarding how much you have left, my recent post is exactly what you need... :)

    According to the data in your pic, you had at least another 79mi to drive, before you could drive another 65mi if the average fuel consumption were 50MPG. So you had a total of 144mi left in the tank, if the MFD error was 6.46%. Based on your single tank, the error is supposedly 3.5% optimistic - but you need more tanks to find you own MFD error.

    My lifetime average below is with average temperature of 8C, 6 months of 16" winter tires a year, 17" stock, hilly areas, 130km/h average highway speed. I have managed to beat the EPA and EU cycle ratings with milder temperatures, even with A/C on and winter tires as you can read here.

    NOTE: I would note regularly average speed as well and possibly average temperature in your area between fuel ups. You can derive a lot of interesting statistics over time, if you wish to do so and since you are starting from scratch, why not... ;)