Prius Eco 58 MPG vs Prius 54 MPG - What's the difference?

Discussion in 'Gen 4 Prius Fuel Economy' started by cyclopathic, Nov 18, 2015.

  1. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    84,762
    37,286
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    highest possible LRR and higher factory pressure. you do not know how much they account for.

    so we're back where we started. more efficient tyres, windscreen, lower weight, no rear wiper.
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,254
    11,774
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    What? o_O

    Tires make a difference. I have Nokian Hakkapeliita WRG3s on now and even though they're the same size as my factory tires and they're LRR, I can tell you I'm getting a slight mpg hit over the Ecopias that came as standard equipment. According to your logic, I should see no mpg hit. Or that I shouldn't see an mpg hit if I change to winter tires.

    Also, the factory tire pressure specs are higher on the Eco so it's tested with a higher pressure. Evidence has shown on PriusChat that bumping your tire pressures up can gain mpg.
     
    bisco likes this.
  3. Jeff N

    Jeff N The answer is 0042

    Joined:
    Oct 23, 2010
    2,382
    1,302
    0
    Location:
    California, USA
    Vehicle:
    2011 Chevy Volt
    One of the issues that Volkswagen recently had to disclose recently was that they cheated on some gasoline model mpg estimate testing by inflating the tires above the VW stated recommendation in the owners manual. It matters.

    Same for the LRR tires. The Prius Eco comes with different super-LRR tires that are great at LRR but receive poor reviews on their other tire characteristics by customers at tirerack.com.
     
    austingreen and Tideland Prius like this.
  4. Gokhan

    Gokhan Active Member

    Joined:
    Oct 5, 2008
    463
    183
    0
    Location:
    Paramount CA
    Vehicle:
    2020 Prius Prime
    Model:
    XLE
    Again, it's a small effect. Maximum-cold-pressure rating on most newer tires is 44 psi. Since Eco and non-Eco models have the same suspension and practically the same weight (especially for suspension considerations), you can use either pressure rating (36/35 or 39/36 psi) on Eco or Non-Eco models with 15-inch tires without any concern. Or go up to 44 psi with some risk of increased suspension wear or increased risk of tire puncture from road hazards, increased wear in tread center, along with increased ride harshness.
     
  5. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,254
    11,774
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    Correct, BUT for testing purposes, the Eco model is tested at 39/36 vs. 36/35 for the core models. There's your difference right there. Also, I was under the impression that the Eco model uses a different set of tires (Enasave vs. Ecopia for the core models).
     
  6. Blizzard_Persona

    Blizzard_Persona Senior Member

    Joined:
    Nov 2, 2014
    1,636
    847
    0
    Location:
    Pa.
    Vehicle:
    2016 Prius
    Model:
    Three
    So in essence..... if you are a porker and weigh 60 lbs more than the average human you will barely yield any mpg gain what so ever over the other Prii? Since the weight is the main diff, I dont see how a wiper delete could do much of anything besides piss me off when i need to use my rear wiper. lol.

    Also, why don't they just bump the factory PSI up on all the Prii models and yield better mpg, not just on the ECO.. kinda shady way to claim better mpg. Why not bump them up to max psi and gain another 2 mpg... just saying!
     
  7. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,254
    11,774
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    :ROFLMAO:. I guess. Or use it to offset the weight (rather than a 60 lb weight penalty if you choose a core model).

    Why? ride comfort trade off. Toyota knows there's a specific subset of Prius owners that only care about mpg and are willing to trade off ride comfort since that's what they've been doing for over 10 years by pumping up their pressures to 40/38 in the Gen 2.

    The other models are designed to sell to the average consumer that haven't considered a Prius before.
     
  8. Lucifer

    Lucifer Senior Member

    Joined:
    Aug 23, 2015
    1,011
    479
    0
    Location:
    Nh
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    30% more strength in the body around the doors, the structure is going to use much less energy just coasting

    .9" lower, a little bit of extra aerodynamics goes right into saving gas

    98hp, less overall ice horse power, ok.... I'm thinking, the more memory a computer has, the more it needs, the more hp a car has, the more hp a car needs just to start, and move.

    Pity the dunlop tires have a 20,000 mile life, if that.

    What??? Volkswagon actually cheated on a test, with overinflated tires, "oh my" 'err, were the test's in Boston?
     
  9. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,254
    11,774
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    *95hp. 98hp is the Gen 3 rating.
     
  10. bwilson4web

    bwilson4web i3 and Prime

    Joined:
    Nov 25, 2005
    22,894
    12,781
    0
    Location:
    Huntsville AL with 2014 BMW i3-REx
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Patience, the EPA has yet to post the 'roll down coefficients' which will give us hard numbers.

    Bob Wilson
     
  11. David Beale

    David Beale Senior Member

    Joined:
    Jul 24, 2006
    5,963
    1,935
    0
    Location:
    Edmonton Alberta
    Vehicle:
    2012 Prius
    Actually, if you are a "porker" you will -still- see a mileage difference between the eco and the other models. You will just get the other models mileage in the eco and lower mileage still in the other models.

    I have said it before and will say it again, the mileage measurements are a game to manufacturers. I can't call it "cheating" to put on useless tyres that wear out in a ridiculously short time, but it sure smells like it. ;) They all do their best to "tweak" the car to improve mileage measurements. The EPA has some regs. built in to catch that, but there are just too many variables. Heck, some apparently actually DO cheat! What a shock! ;)

    I don't see much benefit in the eco model. We all know the "rim protectors" the cars come with don't last very long and provide questionable grip. Just replace with your tyre of choice in a non-eco model. I just put Nokian WRG3 tyres on Pearl S. I find they give the same mileage as the OEM rim protectors, based on experience with Pearl, a GII. They also handle shockingly well! But I inflate at 40 PSI front and 38 PSI rear. So I cheat too.

    Oh, and Tideland, I don't think the WRG3 is a "Haka" tyre. At least not according to the Nokian website.
     
    Tideland Prius likes this.
  12. Gokhan

    Gokhan Active Member

    Joined:
    Oct 5, 2008
    463
    183
    0
    Location:
    Paramount CA
    Vehicle:
    2020 Prius Prime
    Model:
    XLE
    If tires are a significant factor, why do Prius models with 17-inch wider tires and much lower 33/32 psi pressure have the same EPA MPG numbers?
     
  13. David Beale

    David Beale Senior Member

    Joined:
    Jul 24, 2006
    5,963
    1,935
    0
    Location:
    Edmonton Alberta
    Vehicle:
    2012 Prius
  14. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    37,114
    25,928
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I've got the 17", Michelin Pilot's. They seem to run neck-n-neck with Michelin X-Ice we use through winter, fwiw.
     
  15. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    84,762
    37,286
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    the cars all get the same epa rating, regardless of wheel size. the testing is complicated, and not simple to understand. the manufacturers know how to play the system.
     
  16. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,254
    11,774
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    Ohh? ok. Must've shortened it for the 3rd gen. Thanks!
     
  17. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    37,114
    25,928
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I know the WRG2 was an "all weather", sort of halfway between all-season and snow tire. The "3" successor does have a unique new tread pattern, but still in same category. There's also a lower priced tire which has tread that's dead ringer for WRG2, called Norseman, Northman?

    The Haka are really another class, soft rubber, very close spaced sipes; run your hand over and it feels like brush bristles.
     
  18. walter Lee

    walter Lee Hypermiling Padawan

    Joined:
    Oct 26, 2009
    1,126
    374
    5
    Location:
    Maryland
    Vehicle:
    2010 Prius
    Model:
    III
    I agree that a big change acceleratior response could be help with the MPG.
    the curb weight has the biggest effect on fuel efficiency when the vehicle is accelerating uphill from a dead stop.
    The slower the acceleration rate and the lower the top speed the more fuel efficient a car will be - lowering the curb weight means less work is needed to accelerate - so my question would be

    Does the 4th gen 2016 Toyota Prius Eco has the same 0-30 mph and 0-60mph acceleration rate as the standard 4th gen 2016 Toyota Prius?

    I agree that a Li-ion battery could help with the MPG
    When the 3rd gen Toyota Prius traction high voltage (HV) battery state of charge (SoC) is over 73% the Prius goes full throttle on electrical power. The Prius transmission "B" mode avoids charging the HV battery when going downhill to prevent overcharging the HV battery. Toyota did this to extend the lifespan of the HV battery - (why? Reducing the the top SOC reduces the *heat* caused during recharging which lowers the lifetime exposure to material stress on the HV battery). Lowering the max electrical power in a battery reduces the electrical assist during coasting time; Electrical assist during coasting is one of the primary reasons the Prius' MPG is so high. Using an Li-ion battery with more electrical storage power would extend the time that a Prius could do electrical assist during coasting - hence a Li ion battery would result in an increased MPG

    The EPA test does not include thermal loss from driving in very cold temperatures. As the driving temperature drops from 55 degrees to 20 degrees Fahrenheit. - the fuel efficiency for most gas powered cars but it affects the Prius's small Atkinson cycle engine even more so because it burns so little fuel in the first place. To Toyota's credit - focusing on improving the Prius' thermal efficiency will make a real difference in real world MPG performance.
     
  19. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    37,114
    25,928
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I'm thinking too the very good numbers early adopters are getting are due to improved warm-up. I don't think anyone's got a calculated tank yet, let alone 2 or 3 tanks, to cancel out vagaries of the dealership: different fill up technique, test drives, possible protracted idling, and so on. And the info so far is the car's display, daily log. But apparently it's close to accurate, from what Wayne Gerdes' testing.

    I looked at the description of the Canadian 5-Cycle test, and there's mention of both cold-start and low temperature testing:

    5-cycle Testing | Natural Resources Canada

    So far, with limited info, it seems Toyota's hit it out of the park.
     
    bwilson4web likes this.
  20. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,254
    11,774
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    We don't have official NRC numbers though. (Although it has been pretty much the same as the EPA)
     
Loading...