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10mpg increase

Discussion in 'Gen 2 Prius Fuel Economy' started by WNY-HYBRID, May 18, 2014.

  1. WNY-HYBRID

    WNY-HYBRID Member

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    So, I've been steadily getting 42mpg on average. 12v is fine, and dealer just serviced. Had a look at the tire pressure, and they all had 30 psi. Sidewall says 40. Called dealer and complained... He said that the tech believes 30 psi is correct, despite that obvious recommendation from the manufacturer. I filled the tires to 40-42 and boom... 52-55 average mpg. With a little pulse and glide ( not enough to be annoying to others) the mileage is back.

    Check your pressures often!

    Anyone here use nitrogen in the tires? Any mileage increases?
     
  2. KhaPhoRa

    KhaPhoRa Member

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    I use a 78% nitrogen blend, but haven't noticed any difference.
     
  3. ursle

    ursle Gas miser

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    Nitrogen will increase the duration of time between filling your tires back up to 40psi, for example, instead of topping up the tires every two weeks, it might be 6or8 weeks, good for the 50's with a gen2
     
  4. fuzzy1

    fuzzy1 Senior Member

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    I have difficulty believing that all of that improvement is from tire pressure. Did the weather improve too, warmer and drier?
     
  5. bisco

    bisco cookie crumbler

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    agreed. ^^^ maybe a few mpg's but 10 has to be other factors as well. why would a dealer recommend pressures lower than the mfg.'s recommendation? sounds like a lawsuit waiting to happen.
     
  6. WNY-HYBRID

    WNY-HYBRID Member

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    No, nothing else changed. 28-30 psi in each tire, 42 mpg average. Now 42 psi in each tire, and 50-51 average. Instant improvement. Weather is the same. Really don't care what you believe, just stating what happened.

    I don't like it when people assume your not telling the truth. Really annoying .
     
  7. WNY-HYBRID

    WNY-HYBRID Member

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    Regarding the dealer-

    Bought from a brand new honda dealer. A bunch of idiots over there.. Among other things, got my title in the mail, no lien holders, and I have a loan on it.
     
  8. CatsAreGods

    CatsAreGods Junior Member

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    Could be worse, I had it the other way around on my last car years after paying it off.

    Nexus 4 ?
     
  9. xraydoug

    xraydoug Active Member

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    78%? is that just regular air?

    question if you keep filling up your tires with 78 % and the oxegen and other gas in air leaks out quicker how long until you have 99% nitrogen? sounds almost like a story problem from school.:p
     
  10. CatsAreGods

    CatsAreGods Junior Member

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    That was so subtle, I missed it the first time!

    Nexus 4 ?
     
  11. WNY-HYBRID

    WNY-HYBRID Member

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    I actually fill my tires with kittens. I believe That's why my mpg has increased. Not air. Not nitrogen. Small, fluffy, cute, kittens.
     
  12. KhaPhoRa

    KhaPhoRa Member

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    This happened to me with my last vehicle. Nissan Motor Acceptance Corp had the loan and one day they figured out they weren't on the title. They called and at first I agreed to send them the title but the next day when fedex tried to deliver the prepaid return envelope I refused the delivery. I had no bad intentions, I just panicked that I didn't check into who really called me and I worried it was some trick. They kept calling and resending that envelope but never mailed me anything on official NMAC letterhead and at that point I figured I would keep it anyway. I was worried they would try something more drastic like calling in the loan or take it to court but they never did. I made all my payments on time and paid her off. After she was paid for they sent me a different title that showed them as a lien holder, so they were able to get another one issued anyway at some point. I still have the clean title as a memento.
     
  13. KhaPhoRa

    KhaPhoRa Member

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    Obviously that will help.. once you start moving those little kitten legs are going to try and run with the car to avoid spinning around increasing your emm pee geeees.
    I saw it on dateline.
     
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  14. KhaPhoRa

    KhaPhoRa Member

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    HA!! That's exactly what I asked my friend who insisted his $20 nitrogen fill ups were worth it! Great minds (right or wrong) think alike! After just the second top off you'd be at almost 99% if nitrogen doesn't leak at all (it does anyway).

    "So oxygen leaks out a lot faster than nitrogen?"

    "Yes! Nitrogen is too big to leak out."

    "So my free air is almost pure nitrogen by now?"

    "Huh?"
     
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  15. WNY-HYBRID

    WNY-HYBRID Member

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    This thread is entertaining!!
     
  16. xraydoug

    xraydoug Active Member

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    It would seem so after a few years the tire will have mostly nitrogen if the theory that it leaks out more slowly. also with the lack of oxegen inside the tire is supposed to last longer?? all my tires have worn out on the outside long before they wear out on the inside!! I guess over the years I have had one tire sidewall failure so it is concevable that nitrogen could of had an effect on that situation. but I think it is unlikely that it would have made any difference.
     
  17. vskid3

    vskid3 Active Member

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    Were you doing pulse and glide before filling the tires? Tires being a few below Toyota's recommendation probably cost a few MPG, and going to 40PSI probably added a few more MPG over that. Add in the P&G and 10MPG increase is about what you'd expect. Tire pressure can make a big difference. The only increase from using nitrogen is in the profits of the dealer.
     
  18. xraydoug

    xraydoug Active Member

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    I buy my tires at costco they use nitrogen but only put what the door sticker says for psi, that doesent work for me so I pump them up at home. Glad I have an air compressor! I find that with higher psi I am able to pulse and glide much better the car almost coasts forever:D
     
  19. bisco

    bisco cookie crumbler

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    not assuming you're not telling the truth, just think you don't know every factor that might be coming into play. no offense intended.:)
     
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  20. fuzzy1

    fuzzy1 Senior Member

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    How did you figure that?

    I'm not seeing how differential leakage could cause a tire maintained at 35 psi with regular air, to ever fall below about 6% oxygen at sea level, or about 5% at higher elevation. The partial pressure inside should not fall below the partial pressure outside.
     
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