Best way to increase MPG (not including driving habits)

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

  1. HasuPK

    HasuPK New Member

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    Wondering if anyone had any results modifying anything on their prius C to get more MPG? I know tires can make a difference, anything else?
     
  2. PriusCamper

    PriusCamper Senior Member

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    They've already done almost everything possible in your car's design to boost MPG... You could reduce as much weight in the vehicle as possible...

    I also noticed a very slight improvement in MPG in my Gen2 Prius by switching to 0W-20 synthetic motor oil, not good for Winter in real cold climates...

    Also a Prolong hybrid battery conditioning routine Prolong® Battery Systems FAQ – Hybrid Automotive will ensure your hybrid battery is maxing your MPG, especially every 3 months after a full charge and balancing between cells.

    But far and away the best way to boost mileage is Low Rolling Resistance tires with as high of tire pressure as feels safe. The way I did it was kept adding 2-3psi in each tire until I noticed a slight decline in traction under normal driving conditions. In Summer I feel comfortable with 46 psi in the rears and 48 psi in the fronts. In winter driving conditions I lower the pressure by about 5 psi.

    Finally the last option for a major MPG boost is alloy racing wheels that are 4 pounds lighter than standard wheels... Catch is those wheels cost $2K to $3K each, which makes for a really bad day if you hit a curb.
     
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  3. HasuPK

    HasuPK New Member

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    Great write up
    Thank you!
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Try some fuel injector cleaner, one with PEA (PolyEtherAmine), the kind you add to a tank of gas.
     
  5. PriusCamper

    PriusCamper Senior Member

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  6. wjtracy

    wjtracy Senior Member

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    There is a hack known as the "thermistor hack" used on Gen2 and a few Gen3's basic idea is to elecronically fake out the warm-up cycle to get out of the lower-MPG warm-up cycles faster. I know one PiP owner from West Virginny had done it, but the idea lost popularity....guess Prius lost the hobby interest it once had. I do not know if it works on a Prius c. If in Ca. that could be legal issue, as the long, low MPG warm up cycle is CARB's idea to minimize emissions.

    Another idea get out of Hawthorne and get some real gasoline, assuming that is Ca.
     
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  7. pdforever

    pdforever Member

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    I'm sorry, I know that the thread is a bit old, but it came up in my "similar threads" line, so I had to ask...

    Isn't that a bit high? The pressure, I mean. Wouldn't having a tire pressure that high damage the tires? I'd always heard that it should be 30, though I seem to recall reading somewhere that the pressure of the rear tires should be 28 because there's less weight there.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    There's a recommended pressure on the placard in the driver's door opening. I figure it's ok to go a few pounds over but not too much.

    One thing I suspect: extreme pressures will accelerate wear on wheel bearings, shocks and suspension.
     
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  9. ztanos

    ztanos All-around Geek!

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    I would never go 48 psi on a tire that states MAX pressure of 45... I do run 41/42 all around, however.
     
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  10. roadrunner

    roadrunner His (blue) and hers (black).

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    I would suggest the purchase of
    ethanol-free gasoline!
     
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  11. wjtracy

    wjtracy Senior Member

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    Sure that could help...years ago Prius owners had contests about how many miles they could squeak out of a tankful. Yes E0 would be one possible strategy, for those with access to E0. In those days E0 was probably more common.
     
  12. mpg_numbers_guy

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    I've read that tires at sidewall max wear the best - underinflated tires (<40 PSI) and overinflated tires (>50 PSI) have uneven treadwear.

    I run 60 PSI on my Insight and 68 PSI on the Civic. Prius is at 50 PSI for ride comfort (mom's car). Wear hasn't been abnormal at all. There's a guy who runs over 100 PSI in his tires and is fine, albeit vastly increased road noise and suspension wear. Can't recommend that. ;) But sidewall max or just over - definitely recommend.
     
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  13. KK6PD

    KK6PD _ . _ . / _ _ . _

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    Live in a MC Escher reality, always drive downhill.....
     
  14. ztanos

    ztanos All-around Geek!

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    That's a good way to prematurely stretch the beads and wires...
     
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  15. mpg_numbers_guy

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    100 PSI? Yes, that an also a vastly increased amount of wear on bearings and suspension components. 60 PSI? Maybe a little, but I consider it worth it for the MPG gain. Sidewall max? Perfect if you're paranoid about your tires. ;)
     
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  16. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd rather change tires once in a while, and preserve wheel bearings and suspension.
     
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  17. wjtracy

    wjtracy Senior Member

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    I believe MPG guru Wayne Gerdes uses really high tire pressure
     
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  18. mpg_numbers_guy

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    It depends. Inflating the new winter tires on the '08 Prius from 36 PSI to 50 PSI brought highway fuel economy from 43.8 MPG to 47.6 MPG. This is 30 F wintry weather on new tires that haven't broken in yet, so still hurt fuel economy.

    Let's say you only get 50k miles on a set of tires, and gas is $2.50/gal:
    50k mi / 43.8 MPG * $2.50/gal = $2,853.88
    50k mi / 47.6 MPG * $2.50/gal = $2,626.05
    Savings: $227.83 - over half the price of new tires over the life of the tires. Plus better wear at the sidewall max (Michelin X-ICE 185/65R15s are rated at 51 PSI).
     
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