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Sudden Bump up in MPG

Discussion in 'Gen 2 Prius Fuel Economy' started by satwood, Jan 7, 2008.

  1. satwood

    satwood Member

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    Hi Gang,

    I'm wondering if I just experienced the bump up in MPG that other people have reported as their new Prius' approach 6K miles. In my case I drive about 130 miles per day, all highway, with moderate to significant hills (not by west coast standards though). It's RT-290 and Rt-495 for those who know Massachusetts. My average speed is between 65 and 75 and I use cruise control most of the way. I bought my '07 Prius in November and have been getting between 44 and 47 MPG, lower end of the range as the temps got into the 20s here in December. The car now has 5400 miles on it.

    Today I did nothing unusual and I got 52.4 MPG in the first 65 miles of this tank coming to work. The temperature was 45 degrees and there was no noticeable wind. I have the tires at 42/40 psi and the upper grill blocked. I use the block heater and pulse-glide on the roads to and from the highway (when I can get it to do EV only).

    This increase could also be due to the warmer temp but last month we had a couple warm days and my numbers did not go up nearly that much. Is this what other people have experienced?

    Before this I had managed only one tank near 50 and that was with very careful driving -- slowing speed up hills and coasting down as much as possible, keeping the heater off, no CC, drafting trucks, etc. I decided that was too much work for 49.5 MPG and then this morning it just happened. Obviously I'd like to keep this trend going.

    Your thoughts?

    Thanks
    Steve
     
  2. firepa63

    firepa63 Former Prius Owner

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    It's most likely the warmer temperature. My mileage is also up in this warmer weather.
     
  3. qbee42

    qbee42 My other car is a boat

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    Warmer temperature and the fact that you just reset the mileage calculation. The farther into a tank, the less you notice short periods of good mileage (the bumps get averaged out). I get my best mileage readings in warm weather, with a warm engine, right after I fill up and reset. Sometimes then I will average 68 mpg on the 25 mile drive home. After a few hundred miles I will be back to my normal average, which in good weather might be around 54 mpg.

    Tom
     
  4. satwood

    satwood Member

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    I have not been dissapointed with my 44 - 47 range so far, but achieving an average over 50 sure would feel nice. I find the reset calculation can go both ways. If I fill up at night and then drive a couple miles to home, by the time I go through a warm-up cycle the next morning it has to climb out of the 30s and creeps towards it's normal value. Other times I get similar results to yours when I buy gas mid-way through my trip. I filled the car up on Friday and did not drive it all weekend. So, the average this morning started out below 25 in the first 10 minutes and then just kept climbing to 52. The warm weather effect is really significant.
     
  5. qbee42

    qbee42 My other car is a boat

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    Absolutely! If you start up cold with low miles on the reset, the numbers are depressing. I often have a little internal conversation about the ethics of hitting reset again and purging those evil numbers. So far I have resisted, except on one occasion where I wanted to impress a skeptic.

    My better averages come from the fact that I rarely drive around town. We live in a little village, and my wife and I walk everywhere we need to go. My typical trip in the Prius involves driving 30 miles to Traverse City over fairly flat two lane state highway, making a number of stops at various stores, and driving back the 30 miles. The two lane highway (M-22) is posted at 55 mph, but with tourists the actual speeds are often lower. If there is no traffic, the weather is good, and I'm not in a hurry, I'll poke along at 45 or so and get really great mileage. I've turned in runs better than 70 mpg on days like that.

    Tom
     
  6. satwood

    satwood Member

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    That's amazing! I have the same ethics dilema:(. I'm such an incurable engineer I can't even cheat on myself for entertainment purposes.

    I wish they required every fuel injected car to have a consumption computer like the Prius. I find my habits have improved because of the display. Even though I don't make big changes in my behavior on the commute to work, I do skip the trips at lunch and I try to time the lights and traffic much more to minimize acceleration and braking where I can. It makes me much more aware of what I am doing and where I can economize. I think I drive my other cars differently as a result.
     
  7. qbee42

    qbee42 My other car is a boat

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    Agreed. One of the secrets of the Prius is that it teaches you how to drive more efficiently. I too am an incurable engineer.

    Tom
     
  8. Neicy

    Neicy Member

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    I saw a definite jump in mpg around 5K miles, but I also had an alignment and oil change done at the same time. But I do think that part of the increase was the car breaking in. I have seen a jump just in the last two days with the warmer temps we've been getting too. It has been pitiful recently with my short trips.
     
  9. Rae Vynn

    Rae Vynn Artist In Residence

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    No cure required or desired!
    I wonder if the percentage of Prius owners that are some sort of engineer is higher than with other vehicles? I'm thinking that it is ;)
     
  10. Earthling

    Earthling New Member

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    You drive too fast.

    Stick to the speed limit, and/or look for ways to drive slower, like choosing alternate routes.

    You can't expect any kind of mileage doing 75. Not gonna happen...

    Harry
     
  11. satwood

    satwood Member

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    I think if I stuck to the speed limit on 495 I'd get killed. This morning in the right hand lane doing 68 I almost got rear ended by an 18-wheeler who veered at the last minute and passed me doing at least 75. I felt like I was parked :eek:.

    But, I understand your point. In fact, I've tested driving this route in off hours when I work late averaging 55, 60, and 70. I honestly don't see a large difference, maybe 2 - 3 MPG. This morning with the cruise around 68 I still put the average back at 52.4 by the time took the exit. So, I try to go with the flow of traffic and pick a speed that doesn't make me a target. I would speculate that the hills have as large an effect on comsumption as the difference in speed/drag does.

    Thanks for the feedback everyone!
     
  12. TimMan

    TimMan AC or Bust

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    I would agree w/everyone......slower speeds and cold weather have a big impact on your MPG.

    I finally decided to drive 65mph, the posted limit. What a difference, my ride on the AC XpressWay was an average of 56mpg.

    I saved a screen shot from my display to show off! :)
     

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  13. Tripod137

    Tripod137 New Member

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    You should try to find the "sweet spot" for the temperature. Example, when it was warmer, I would get incredible MPG by going 51mph. REadings were in the 70's - 90's and this happened on multiple days. Another magic speed for me has been 65mph. This one has yielded very high MPG.

    I guess it depends on the temperature where the "sweet spots" are.
     
  14. icarus

    icarus Senior Member

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    I agree that you get better mile by going (generally) slower. But 50mpg+ is doable at speeds faster than 65mph.

    We did a fall trip across the northern tier and back. ~5000miles. Speeds beter than 70 all the time, often as high as 82. We averaged just at 50mpg for the entire trip. We had 600 miles of howling head winds (50-70 mph) returning across N.D and MT. Without those two tanks we would be perhaps 1-2mph better.

    We did a series of test for long durations of 55mph, then 60mph, then 65 mph, on up to 75. It seems that the sweet spot balance between getting there and getting the best mileage was around 68mph.

    Good luck,

    Icarus
     
  15. TimMan

    TimMan AC or Bust

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    I will agree w/both of you that the slower you drive the better MPG. I live in the NE and it is unthinkable to drive any slower than the posted limit because of safety. If it 65 mph, then I drive it and by doing so I finally starting seeing my daily 160 mile trip showing 50+ MPG. I am very happy w/this and in my oipnion buying this vehicle was a smart move and will pay for itself.
    Any thoughts??
    Thanks again guys.
     
  16. BoltonJoe

    BoltonJoe Junior Member

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    Hey Steve,

    I've just experienced the same dramatic bump in mpg. I bought my Prius just after Thanksgiving (Nov. 28). I was getting mileage in the 35-40 range. Then, just before the weather turned warm, I blocked my grill.

    And the mpg started to go up.

    Now that the weather has been in the 50s, I'm getting 53-54 mpg. per tank. My odometer reading is now approaching 3k, so the car is well broken in. And, I'm learning how to take advantage of hills, as well as using my cruise control.

    I tend to avoid Rte. 495, but I do take the Mass Pike extension and a stretch of Rte. 93 every day. I know that this has something to do with better mileage: I travel roughly half of my commute on secondary roads and half on the Pike.

    On the highway, I try to keep the cruise control set at 65 mph, but in some places here in Massachusetts, as you know well, that's a good way to get yourself killed--even if you stay in the right lane.

    --Joe
     
  17. satwood

    satwood Member

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    Hey Joe,

    Maybe it's a Massachussetts thing, we're both getting a mileage bonus with the January thaw. I'm surprised you were getting 40 on your route, which I think is flatter than mine among other things. I would have expected your numbers to beat mine. Lets keep track of each other and see how we do over the spring and summer.

    Steve -- Go Pats!