Are people really getting 40+ MPG in Gen 2?

Discussion in 'Gen 2 Prius Fuel Economy' started by timmyjane, Apr 12, 2017.

  1. fuzzy1

    fuzzy1 Senior Member

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    External racks are simply incompatible with high MPG and hypermiling, in any car. Either lose it, or reduce you expectations.

    The fast lane is also not conducive to average or better MPG on any car model.
     
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  2. Kaptainkid1

    Kaptainkid1 New Member

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    I think you might got my Roof Rack mistaken for a Roof Rack with a box. I run the thule box when I go on long trips and need extra space. I also expect to lose miles when running a box. Otherwise I leave my roof rack on the car all the time. I assume the drag created by racks are minor maybe 3mpg loss at best. Why do people think the racks are like sails. (Jerrymildred).
    20190314_142703.jpg

    20190314_142638.jpg Prius.jpg
     
  3. mpg_numbers_guy

    mpg_numbers_guy Junior Member

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    New tires will also reduce your MPG some until they "break in".
     
  4. fuzzy1

    fuzzy1 Senior Member

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    Don't assume it, test it.

    Even on my old gas hog Subaru, when gas prices spiked, I took to removing the factory crossbars when unused. Your non-factory towers look worse. If your crossbars are round instead of airfoil shaped, then they are worse too.

    Experience on prior cars.
     
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  5. jerrymildred

    jerrymildred Senior Member

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    I agree with @fuzzy1. It's not just the frontal area of the crossbars. It also the way they dirty up the airflow over the top and rear of the car. That reduces increases the coefficient of drag for the whole area.

    edit: OOPS!! That was a dumb typo. Thanks, @fuzzy1. Somehow, proofreading my own typing doesn't always help. :oops:
     
    #225 jerrymildred, Mar 14, 2019
    Last edited: Mar 15, 2019
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  6. fuzzy1

    fuzzy1 Senior Member

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    ... increases ...
     
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  7. ericbecky

    ericbecky Hybrid Battery Hero

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    Of you remove the rack and drive exactly like the EPA test in conditions that are the same as the EPA test, you will get the EPA rated mpg.

    Roof rack and interstate speed (or higher) will certainly kill mpg. I'm talking about roof rack with nothing on it.

    Take it off, drive at highway (not interstate) speed, you will see what the car is capable of.

    You said you keep tires properly inflated. That's good. Any idea if you have stock, low rolling resistance tires on it. (Sorry if I missed it in the discussion.)
     
  8. Kaptainkid1

    Kaptainkid1 New Member

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    I'm running Hankook Optimo H727 which are all season tires and they are not LRR tires but I've read they have good reviews. Also I'll pull off the Racks and see if I would get better MPG. So far after resetting my mpg avg on the MFD and hypered mile all day driving I've noticed my mpg went up to 42mpg. Not the type of driving I like to do in the city. I'm the A-hole Prius driver holding the traffic because I'm trying to only accelerate using only my slow electric motor. Now I know why Prius drivers suck because car is designed to encourage crappy drivers. Lol.
     
  9. Devdas

    Devdas Junior Member

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    My gen 2 Prius averages between 50/55 mix use motorway driving and city driving it has 130,000 miles on the clock regular maintenance
     
  10. jerrymildred

    jerrymildred Senior Member

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    That'll really kill your gas mileage! If you run down the battery like that, then the car has to recharge the battery more than it normally would and there is always energy lost in that process.

    I've read that the most efficient rpm would be where your mpg number is between 50% and 100% of the speedometer. ie: 15-30 mpg at 30 mph as you're accelerating. That seems to be true for our gen 2. It's still slower than traffic wants to go, though.
     
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  11. dolj

    dolj Senior Member

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    +1 to the above advice from @jerrymildred. I was about to say something very similar.

    The car was not designed to be driven in the way you described and as Jerry said, you will actually hurt your MPG (as you have demonstrated). You would be better off just driving normally, as that is how the car is designed to be driven, no need to be the A-hole.

    My current tank is sitting on 59 MPG (71 MPG (UK)) and I do not drive slow. It was at 62 MPG (74 MPG (UK)) earlier, but then I had to do some hills! By the end go the tank it will probably settle around 53 - 56 MPG.

    Get up to speed quickly – 20 MPG (slow) - 11 MPG (faster) on the Energy Screen, and engage the ICE, do not try and use electric.

    The best hypermiling technique is Pulse and Glide. Again, get up to the speed of the traffic and then pulse to 33 MPH. Glide down to 29 MPH. Rinse and repeat. Adjust the numbers to work in with the traffic around you. You will find this works remarkably well and is easy to do in an urban environment as most people can't maintain a constant speed.

    Second hypermiling technique is anticipation, both slowing down and accelerating.

    You will know when you're doing it right because the battery graphic on the Energy Monitor screen will be at 6 - 7 bars a lot.

    Hope that helps.
     
  12. jerrymildred

    jerrymildred Senior Member

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    Hard stops seem to me to be as bad as hard acceleration for gas mileage, too. That gliding and/or regenerating as you approach the queue of cars or the light makes a huge difference. And then you get to use the energy you stored regenerating rather than having thrown it all away in heat and brake pad dust.
     
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  13. fuzzy1

    fuzzy1 Senior Member

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    On top of that lost regeneration from hard stops, there is also the extra fuel burned earlier to maintain speed, or even to produce extra speed, when one could have been gradually gliding down fuel-free to the impending stop.

    Hard stops are also commonly associated with lost timed-light opportunities, where early slowing or gliding can mean saving some speed and kinetic energy by avoiding needing to stop altogether.
    This is less beneficial than many drivers realize. The savings from proper gliding to stops is much greater. And above about 15 mph, this electric-only acceleration actually works against you, not for you. So don't be an A-hole, get your fuel savings elsewhere.
     
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  14. VFerdman

    VFerdman Senior Member

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    I noticed that you are from UK, so I have to clarify. When you state 50/55, I assume it's MPIG, that is Miles Per Imperial Gallon. Please clarify the units for us as it make s a big difference. It took me a while to understand why our fellow Prius drivers from UK are getting so much better gas mileage. Then I realized you guys are using Imperial Gallons, which are larger than US gallons (Why?!!!! Let's just all use metric!). If I am correct in assuming your gallons are imperial, then your numbers should be divided by 1.2 to make sense to US readers. 50/55 then becomes 41.7/45.8, which makes a lot more sense and is pretty much normal healthy Gen 2 fuel economy.
     
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  15. Zeppo Shanski

    Zeppo Shanski Junior Member

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    I've got 3 pips on my gas guage. I made a mistake this morning and saw my mpg consumption. I'm running @ 49.8 mpg. I wanted to wait until it got to 1 pip ... but now LOL ... I don't want to lose that 49.8 mpg. I guess I'm just gonna keep driving nice.




    2005 w/ +/-143,000 miles.​
     
  16. srellim234

    srellim234 Senior Member

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    That's correct.

    Fuelly.com has the 2008 Prius averaging 42.9 Mpg or 51.6 "UK MPG" with entries from 587 vehicles over 16.7+ million miles. That means that for every 50 mpg U.S. car there are three others getting 40 or less.The four 2008 Prii still being reported at fueleconomy.gov are at 40.6, 42.9, 45.7 and 45.9 U.S. mpg, respectively.

    Kaptainkid1, for not having LRR tires, your acceleration technique and dragging an empty roof rack you're probably right where you should be with regards to your fuel consumption.
     
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  17. George W

    George W Active Member

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    Many members of The Forum over inflate their tires just a tad. 42 front and 40 rear seem to be a good combination for most generation 2 drivers
     
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