Best way to increase MPG (not including driving habits)

Discussion in 'Prius c Fuel Economy' started by HasuPK, Jul 10, 2018.

  1. Mendel Leisk

    Mendel Leisk Underfoot

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    ^ this.
     
  2. douglasjre

    douglasjre Senior Member

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    Overinflated tires make fast bumps travel to the shocks. The gas charge should reduce cavitation but as shocks age the nitrogen charge drops from 150psi to nil. With age this becomes a real problem and shocks fade quickly as oil bubbles and foams. You'll bounce your way down the road, have little traction and wear the tires out quicker from cupping. The ride will be harsh too. Rolling resistance is a small part of the total energy losses.

    Anybody here have data on the fractional part of total energy lost to rolling resistance? And, the mpg impact overinflation provides?
     
  3. wjtracy

    wjtracy Senior Member

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    There have been some past discussions here...but I am rusty
     
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    The c model already features 175/65R15 tires (unless it's a four trim with the optional 16" wheels).

    Your comment is more applicable to the big Prius, which is usually (but not exclusively) discussed in other subforums.
     
  5. CR94

    CR94 Senior Member

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    Nobody can give you that fraction as a fixed number, because it's totally dependent on speed. Tire rolling resistance force is (almost) constant regardless of speed, while aero drag force tends to be proportional to the square of the speed. Therefore aero is insignificant, compared to tire drag at very low speed, but is much larger than tire drag at high speeds.
     
  6. douglasjre

    douglasjre Senior Member

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    Anybody have a solution to run this thing in a lean burn mode?
     
  7. Zeppo Shanski

    Zeppo Shanski Active Member

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    I’m interested if someone could explain for me the relationship between over-inflated tires and effect on wheel bearings.



    TIA for some help here.
     
  8. 9001MPG

    9001MPG Junior Member

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    I dug up some info on what the rolling resistance labels really mean. Tires sold in the EU must have the EU tire labels attached to them, as such many manufacturers will make them available (although, not always readily visible). They can often be found by googling for tire make / model and EU Label as search tersm.

    The numbers indicate kg's of rolling resistance per ton of vehicle mass. See PDF attached for full info.

    Rolling resistances for C1 class vehicles (personal vehicles, if I recall correctly), are classified as follows:

    upload_2022-9-10_19-51-40.png
     

    Attached Files:

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  9. PriusCamper

    PriusCamper Senior Member

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    Anyone got a list of Class A Tires in the EU are also sold in the US?
     
  10. lech auto air conditionin

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    I bought the thin70,000 mile continental tires run them at 51 PSI . I’m just changing them now at 61,000 miles

    hard loud ruff ride expected
    You don’t get something without giving up something

    compared to my wide 205/55/15 summer only race sticky tires is the best way to drop 12 mpg but boy are they fun to corner fast turns on.

    can’t wait to jump up to 215/50/16 just to install for fun day of driving only. Then remove back to boring driving
     
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  11. PriusCamper

    PriusCamper Senior Member

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    How did the tread wear look on them when they were done? I often argue that it's a myth that over inflated tires will have more wear in the center because steel-belted tires are NOT like balloons that no longer sit flat when over inflated. Also on my last set of ecopia at 47psi in front and 45psi in rear I got 10K additional miles than tires were rated for and wondering if higher PSI was why? Thoughts?
     
  12. lech auto air conditionin

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    I’ll take photos and post them I have not dumped the tires yet they’re still on the rims in my garage

    I rotated the tires every 5000 miles with my oil change.

    As you know I use my car as my work vehicle mobile business traveling between business stops on a daily route in excess of 30,000 miles a year. My vehicle never has less than a little over 800 pounds of equipment and supplies and tools in my vehicle

    I have that massively large oversized roof rack that came from a large van with the extender added making it as long as from the front windshield to within 1 inch of opening up the rear deck lid just before it touches and hanging over each side of the left and right passenger window

    The vehicle also has a tow hitch added to it that I used to bring my equipment and supplies between jobs either my 4 x 4 trailer or a 5 x 9 trailer carrying in excess of 1000 to approaching 2000 pounds yes I know that little car it is not recommended don’t have to tell me about that . But if you see what they do to small cars in India and Pakistan in the Philippines and the remote country side of China and small utility vehicles used in European countries after seeing that I was willing to do the same thing started with my 1988 Chevy sprint three cylinder was loaded up the exact same way .

    I have a little over 151,000 miles on this vehicle and I still have the front brake pads original travel in the streets in the hills of San Francisco.

    definitely durable indestructible vehicles. Properly maintained. But massively abused

    yes on some vehicles depending on the loading and the type of tire if you do over inflate them they will go bald in the center.

    The wire the tire is the worse and faster you will see the result this coming from somebody who used to work at Goodyear tires and did all the alignments I would see the results of over inflated tires or under inflated tires.

    it all depends on how high for the vehicle weight the type of driver lack of rotation.

    but for best mileage with gas if you’re paying six or seven dollars a gallon in California sacrificing a little life of cheap tires but be careful because you lose braking distance.

    Because you have hard rubber in the first place on a high mileage gas miser tire and then by overinflating it you decrease the footprint contact pad area by writing the tire a little more on the center treads instead of cross the whole band width of the tire in a larger footprint as it stinks in to the Asphalt with lower tire pressures giving you better braking.

    Does hasta be accounted for in your driving habits to stay longer distance away from the car in front of you if you were a tailgater in stop and go traffic you will find out a bad results that you were normally able to stop before your vehicle will no longer be able to stop in that short of distance
     
    #52 lech auto air conditionin, Sep 12, 2022
    Last edited: Sep 12, 2022
  13. douglasjre

    douglasjre Senior Member

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    I want to do a lean burn mode of 16.7 to 1 from about 1,300 RPMs to 3000 RPMs. HP tuners software doesn't support Prius. You guys have any ideas
     
  14. lech auto air conditionin

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    constantly holding it at 16.7 to 1. I could understand why the EPA wouldn’t want it lol

    depending on the load conditions there will be some misfire if it’s constant it’s possible burnt valves .
    But it would be interesting to see just not on my engine

    Lien is nice if there’s no load
     
  15. douglasjre

    douglasjre Senior Member

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    We already doing it on Corvettes. I just need the software that supports prius. Anybody got to work around? Like a resistor in line in the oxygen sensor or some other thing
     
  16. douglasjre

    douglasjre Senior Member

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  17. lech auto air conditionin

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    These are continental tires that were rated for 70,000 miles I got 61,000 miles out of this point if I push them to 70,000 I’ll probably have slicks

    I run them at 51 psi all the time. for their entire life from the day I installed them on the vehicle.

    if I try to do the exact same thing with a very wide profile tire like 205- 50-15‘s they will go bald in the center but that is to be expected from a wide tire

    but on a very small tire fin factory size and I carry a heavy load in my vehicle you can see the tires are wearing pretty evenly and the rotated every 5000 miles when I change my oil.

    I have skipped tire rotations two times When I was so busy I cannot change oil at 5000 miles I went to 10,000 miles.

    I cannot find a fourth tire I do not know where I put it to include it in the image 7BE46586-710E-4BE8-A334-9BB771E780BB.jpeg 56CBD5A6-C7EA-4796-90BE-F6BFA46BD33C.jpeg
     
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