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Doing the numbers on the 2007

Discussion in 'Gen 2 Prius Fuel Economy' started by fo0bar, Nov 18, 2008.

  1. fo0bar

    fo0bar Junior Member

    Joined:
    Jun 16, 2007
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    Location:
    Reno, NV
    Vehicle:
    2009 Prius
    Last month I traded in my 2007 Super White #4 for a 2009 Driftwood Pearl #5. During the course of owning the 2007, I was religious about writing the mileage down on gas receipts and throwing them in an envelope in the top glove box. At first it was basically for legal reasons. I live in Reno, Nevada but bought the 2007 from Auburn, California, about 90 minutes away. California has this craziness where if you buy from a California dealership and live outside the state, you 1) cannot bring the car back into California for 90 days, and 2) must prove that the car was operated primarily outside of California for the first 6 months, if questioned. Traditionally this is done with gas receipts. After the first 6 months, I just continued out of habit.

    After the trade-in, I dumped all the receipts to a spreadsheet, and here are the results:

    • 49 fill-ups, first unknown, second on 2007-06-14, last on 2008-10-13 (I noted a base mileage of 135 on the first fill-up, but didn't record the date.)
    • 20,026 miles driven, 19,667 miles counted as part of this data (first fill-up was at 135, last fill-up was at 19,802)
    • Average 410 miles, 9.266 gallons between fill-ups
    • 444.749 gallons consumed
    • Gas prices: minimum $2.759, maximum $4.299, average $3.399
    • Gas prices changed an average of 12.6 cents between fill-ups
    • Average fill-up: $31.58
    • Total spent on gas: $1515.89
    • Lifetime fuel economy: 44.22 MPG

    Gas mileage was a bit lower than I expected, though by looking at the trends on the spreadsheet, it looks like it was mainly when I moved about 7 months ago. I used to live about 15 miles from work (30 miles round-trip), but moved to an area 5 miles from work (10 miles round-trip). Shorter trips lower fuel economy no matter what kind of car you have, but that is offset by the fact that I'm simply driving fewer miles per day.

    I would have hoped for higher MPG, but it's mostly my fault, as I tend to "just drive", rather than watch how I drive. Still, I'm happy. I have the spreadsheet lying around somewhere, if anyone is interested in the raw numbers.
     
  2. max2prius

    max2prius Junior Member

    Joined:
    Dec 19, 2007
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    Location:
    Walnut Creek, CA
    Vehicle:
    2008 Prius
    Just curious,

    How come you decided to trade the 07 for an 09, which everything is the same about the car except for the Navi?


    John
     
  3. fo0bar

    fo0bar Junior Member

    Joined:
    Jun 16, 2007
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    Location:
    Reno, NV
    Vehicle:
    2009 Prius
    A few reasons... Basically, I "settled" in 2007. I really didn't like the white color, and wanted the nav system, but couldn't find a better combination so I got the white #4. I was offered a very decent trade-in on it, so I figured I'd like it best if I got what I wanted in the first place, so it'll easily last another 5 years, as my 02 Prius did.
     
  4. tochatihu

    tochatihu Senior Member

    Joined:
    Apr 10, 2004
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    Location:
    Kunming Yunnan China
    Vehicle:
    2001 Prius
    fo0bar, if you have the other vehicle expenses (maint, insurance, etc) and the buying and selling price of the car you can calculate your totoal cost of ownership in cents per mile. In must cases where Prius owners have done this they have obtained nymbers well below the national average which was high 50's cents per mile (several years ago). I reckon that fuel cost was 7.7 cents per mile for you.

    Care to run the other numbers?
     
  5. xsmatt81

    xsmatt81 non-AARP Member

    Joined:
    Mar 27, 2008
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    Location:
    Vegas
    Vehicle:
    2007 Prius
    cool. I am in the want to either trade in or try to sell next year boat. for the same reason, color. The black prius is driving me crazy, and I just don't like the color..what a dumb choice.

    Will hold off though for 2010 or 2011 model. Or by that time may change mine and get some with a stick shift, have a feeling manual cars are going be very hard to find in the coming years. They already are in fact, unless you go used.
     
  6. ChadK

    ChadK New Member

    Joined:
    Nov 26, 2008
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    Location:
    Detroit
    Vehicle:
    Other Non-Hybrid
    We had a "08" in where I work on a very repeatable dyno facility ($15,000,000), and the numbers that I got were an average for the EPA city/hwy of 31.2 MPG, and 29.8 in the more real world simulation of I75 through Kentucky and Tennessee driving 60 MPH, how do you guys see 44.22? What is your method of calculation? How accurate are you being? It seems that you have a lot of data to back it up, but so do I, I am just trying to figure this out.
     
  7. donee

    donee New Member

    Joined:
    Aug 15, 2005
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    Location:
    Chicagoland
    Vehicle:
    2010 Prius
    Model:
    III
    Hi Chad,

    You probably need to learn how to use the climate controls with regards to you your real world result. Set the heater on max, with the windows open will force the engine to run all the time. Its a closed-loop climate control. One sets it to the interior temperature one wants , not max, or off. Works for cooling as well as heating. Oh, and slaming on the brakes denies the car of regeneration. And you probably want to follow the recommendations of the President Elect and pump the tires up above 15 PSI. And the Prius is not rated for E85. Only E10.

    I have never seen worse than 40 mpg in my Prius ever (below zero weather at the start of that tank, then stuck on an interstate creeping along at 10 mph for 20 miles with so much snow the car had 6 inches on it when I got home at the end of the tank). Driving home into all sorts of head and frontal winds, 15 F temperature, at 70 mph cruise control from where I bought it 384 miles away, brand new car, 43 mpg.

    The new EPA methods seriously underestimates the Prius suburban commute fuel economy. In the real world, one cannot cruise at 70 mph that long in any metropolitan area during rush hour. Last year from March through November, I did not have a tank worse than 58 mpg. Which if you will remember is very close to the old EPA method combined rating for the secong generation Prius. That was doing the interstate commute both ways, cruise control at 62 mph unless traffic was bad. This year, I am hypermiling and have had a few tanks near 70 mpg, with one at 70.1. For the same period all the tanks have been greater than 60 mpg, and this last tank was 64.1 mpg. This hypermiling consists of cruising at 53 mph / 1280 RPM , when SOC is greater than 60 when on the highway, and pulse/glide technique on secondary roads, limiting accellerations to 2400 rpm, but usually around 2000, better awareness of traffic light patterns, and routes that keep the car warming up, once started. The length of the commute is 23 miles one way. No drafting (as if any 18 wheel truck goes 53 mph around here!), no red light running, and no rolling stop signs like everybody else on the road around here.

    Is that dyno facility collecting all the exhaust gasses into bags, like the EPA does? Then analyzing the gas to calculate fuel consumption? Or are you just estimating gasoline usage by pumping the room temeprature gasoline (rather than the standard subteranean temperature) into the car's balloon , er gas tank? If you park the car outside in 20 F weather, then run it at 65 F all day long on the dyno, that gas tank is going to allow at least one additional gallon then when it was full at 20 F, at the end of the day when its 65 F. So, you might subtract 1 gallon out of your Dyno results, and see if they do not match the EPA.

    I think you would do better to ask people how they are driving their cars, rather than how they are calcuating their mileage. Because there are significant differences in the Prius gas pedal and brake usage than other cars. You admidtedly have had maybe a day behind a Prius steering wheel. Maybe more, but that is apparently what you admit too.

    The Prius accellerator pedal is just that. Its not a throttle pedal, its not tied by a cable to the throttle valve like other cars. So, if you hold it at a constant fairly depressed level, as is neccassary to make other cars function properly, the Priusl result in a different mileage than if when you want to cruise, you pull it all the way back , to just short of the car decellerating. This is like the galalean ideal. When you want to proceed along at a constant speed, the proper position of the galelean ideal accellerator pedal would be with one's foot completely off it.

    Braking sooner and longer will regenerate more electricty too. As the batteries do not have infinite power. This is kinda hard to do when tail gating (sometimes misconstrued as drafting).