The most fuel-efficient cars- Consumer Reports

Discussion in 'Fuel Economy' started by JohnM, Oct 28, 2014.

  1. JohnM

    JohnM Well-Known Member

    Measuring fuel economy is among our more than 50 tests we conduct on each car we purchase. Our fuel economy numbers are derived from a precision flow meter and are rounded to the nearest mile per gallon (mpg).

    The chart that follows features the most fuel-efficient cars currently sold that Consumer Reports has tested:

    https://autos.yahoo.com/news/most-fuel-efficient-cars-100000918.html
     
  2. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    John, any chance you guys could test tire rolling resistance? Or have you already?

    BTW, your fuel economy results seem strangely low, doubly so with present company. Also, with the Prius 4: you have a city value of 32 mpg, and highway value of 55 mpg. The official ratings for this car show higher mpg for city use.

    I'm by no means an effective hypermiler, just a duffer who tries. That 32 mpg city translates to 7.35 liters per 100 km. Personally our worst tanks were still in the 5.~ liter per 100 km. And our OEM tire is the low profile 215/45R17. And for almost 5 months of the year we're rolling on Michelin X-Ice2 in 195/65R15.

    This is a bit of a head shaker.
     
  3. seftonm

    seftonm Veteran Staff Member

    Their city test could be exceptionally hard. FWIW I have seen around 8-9L/100km averages in the Prius taxis here.
     
  4. timw4mail

    timw4mail Well-Known Member

  5. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Their city test , unlike the EPA's , starts with a cold engine. Big difference.

    All testing is done differently : EPA has one result , CR has another , I have mine , Wayne has his ( slightly higher,lol ). Find some testing regimen you can relate to , then use that to compare cars.
     
  6. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    A cold engine start seems like a fair test of real world
    settings. I sometimes feel that the tests we see done
    just represent "best case" for the particular environmental
    conditions. Nothing wrong with that, just somewhat
    misleading to those who don't think about test conditions.

    Cheers,
    Bill
     
  7. RedylC94

    RedylC94 Well-Known Member

    Very good points, Edwin!

    In general, CR's tests, both city and highway, are aimed at imitating an "average" ordinary US motorist, not a typical CleanMPG poster, and not the EPA.
     
  8. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    A cold engine start will drastically skew the numbers depending on the trip distance. Is it a 15 mile trip or a two mile trip ? People ( slack-jawed ignorant consumers) NEED to learn a few things about cars. A short trip will always return lower fuel economy than a longer trip with any ICE vehicle. I'd say the EPA testing is a good way to measure city fuel economy.

    USE FOR COMPARISON ONLY. YOUR MILEAGE MAY VARY. Duh !


    And I don't much care for CR , if you couldn't tell.
     
  9. phoebeisis

    phoebeisis Well-Known Member

    C-R City method ac-tually cl-osely matc-hes what many "normal" drivers report for pure c-ity driving.
    Now 32 mpg ci-ty for a Prius-is about what my wife gets when she does her"tanks" of short trips (-maybe just .9- mile but averaging maybe 2-3 miles)- with dead cold engine.
    And C-Rs terrible ci-ty mpg-for 1/-2 ton pickups-pretty muc-h what "normal" drivers report when they aren't lying.

    Oh keyboard got sweet tea with lime c-hunks spilled on it-henc-e the - - after C-'s and zeros
     
  10. ksstathead

    ksstathead Moderator

    If normal drivers only get 32 city in a Prius, then we can educate our way to energy independence, because that is frightfully low.

    Hard to square that with a 55 highway mark that is respectable. Cleanmpgers would do better, but only a little.

    We should normally double their city mark.
     
  11. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    The Pepsi Syndrome, lol.
     
  12. some_other_dave

    some_other_dave Well-Known Member

    Switch to 7up: It won't cause a meltdown; it's the un-cola!

    -soD
     
  13. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The numbers are surprisingly low for all the vehicles. Just no way in some cases. I know of nobody that has averaged 31 mpg in a Prius. Nobody.

    Wayne
     
  14. waltermlee

    waltermlee Well-Known Member

    If I didn't hypermile - I probably would get fuel efficiency closer to the Consumer Report MPG rating on my 2010 Prius. My sisters in Michigan are getting about 45 mpg (they don't hypermile)

    The following lowers fuel efficiency on a Prius
    ===============================

    (1) Driving temperatures lower than 50 F ,
    (2) trips shorter than 5 miles,
    (3) frequent stops and accelerations at the bottom of a steep hill,
    (4) speeds over 55 mph,
    (5) getting into traffic jams (stop and go city driving less than 15 mph) for longer than 15 minutes , and
    (6) using cruise control at speeds under 60 mph.


    The reason these driving scenarios lower the Prius fuel efficiency
    =============================================

    (1) When outside driving temperature drops below 50 degrees Fahrenheit and driving at speeds under 40 mph the ICE shuts down frequently to conserve on fuel usage - but at colder temperatures the engine and the coolant system can lose thermal energy quickly. When the emission system temperature drops below its peak efficiency temperature range the Prius ICE will startup automatically to reheat the emission system and keep it running hot regardless of whether the car is moving or not - this can lead to a lost of 7 mpg per trip as measured by a Scangauge II in cold weather. In cold stop and go traffic - this can happen very often - grill blocking can mitigate thermal loss at low speeds but not when traffic jams last longer than 15 minutes. In stop an go traffic - especially in cold weather, the Prius needs to be in power mode so that the ICE is used as often as possible when you need to move forward - because the ICE needs to run to keep the emissions system warm.
    This is not a problem on the highway. When the Prius is constantly going over 50 mph - the ICE is rarely turned off automatically so the emission systems stays hot .... no grill blocking is necessary, and fuel efficiency tends to be pretty good in the winter if you constantly drive about 40 to 50 mph for over one hour.

    (2) The Prius aggressively runs the ICE for the first five minutes of a cold start to heat up the emissions system to its optimal temperature range at the expense of fuel efficiency - however, once the emission system is at its optimal temperature, the Prius fuel efficiency jump. Operating a Prius for less than 30 minutes/7 miles at a time reduces its fuel efficiency but a Prius' MPG performance tends to really look good when your commute is over 45 minutes/12 miles. Toyota's 400watt Engine block heater can mitigate to cold start warmup penalty for a regular Prius Hybrid.

    (3) To get a Prius going over 25 mph uphill from a dead stop can often causes the ICE to run in power mode where it is least efficient.

    (4) The Prius MPG peaks when driven at about 25 mph (about 80 to 90 mpg ) for over one hour and drops linearly as the Prius' speed increases to 80 mph (about 35 mpg) where the fuel efficiency levels off more or less around the 30 mpg at 100 mph.

    (5) In stop and go traffic jams where speeds are less than 15 mph and that last longer than 15 minutes, the Prius' tendency to use the electric motors will quickly deplete the High voltage (HV) battery power reserves and cause the the Prius to automatically and aggressively recharge the HV battery back up to a 50% level - often while the Prius is standing still. This will cause the Prius' overall MPG performance to drop like a rock. This can be mitigated by putting the Prius in power throttle mode and relying on the ICE to move the Prius at low speed via hypermiling mini pulse and glides - while driving in extended traffic jams - the Prius does not have a only ICE button - using the electric motors persistently in a traffic jam is less efficient because the kinectic power derived electric motors driven by batteries which were recharged by burning gas to run ICE create electricity is less than the kinetic power derived from an ICE burning gasoline. The challenge with using only gas at low speeds is that it is very easy to accelerate too fast and burn too much energy in stop and go traffic jam scenario with a Prius. A Prius is heavy and will roll at a low speed longer than most cars as long as the regenerative brakes are not activated - often a mini pulse and glide doesn't need to be too fast for the Prius to *roll* for a very long distance. The best solution is to avoid being in a traffic jam either by changing your route or the time that you are driving.

    (6) if the Prius avoids using its regenerative brakes and allows the speed to vary - it is more fuel efficiency because the loss of momentum/speed due to variable aerodynamic drag when going less than 60 mph is less than the loss of energy from translating kinetic energy to electrical energy via the regenerative braking system. Cruise control will use regenerative braking to keep the speed constant but the energy recovery from 10% to 50% - at speeds lower than 60 mph variable aerodynamic drag from driving at a variable speed from 40 mph to 60 mph is less of an energy loss factor than the energy loss from using regenerative brakes to keep a constant speed - hence at lower speeds from 40 mph to 60 mph - Driving with Load (allowing the car to vary its speed rather than using cruise control) can increase MPG performance considerably. At speeds over 70 mph aerodynamic drag loss is more significant and regenerative braking occurs less and cruise control starts to make sense.

    clear as mud? awe heck just drive the car and forget it. :)
     
    Last edited: Dec 27, 2014
  15. thunderstruck

    thunderstruck Super Moderator

    Will be interesting to see how the Jetta with the EA288 does, now that is uses urea. I can and have beat their results in my Passat. I've managed to get over 60 in edge of city driving a number of times. It's all about motivation.
     
  16. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Nathan:

    Even journalists are crushing EPA in the EA288s although there is that new over report problem with themand the Audi's. :(

    Wayne
     
  17. The Doctor

    The Doctor Old Dude, New Car

    The forum software tells me I've not posted in quite a while, and I'm encouraged to post, so here goes:


    I'm Hurt! Not one mention in all those test results, about the Kia Soul.
    My little 2013 Soul, Base Model, with 1.6L, 4 cyl., DOHC, VVT, engine, is a real power house and gives me great performance, plus really good mileage.

    Thanks to this forum, I have the Scan Gauge II installed in my car and I let it help me drive my car for the best economy.

    Twice a year (or so) I make the trip from the Ocala, FL. area to Daytona Beach for one event or another. Most of the trip is on US 40, a 55 mph two lane highway. So it's easy to set the cruise control at between 55 and 60 and just sit back and relax and enjoy the trip.
    I like to watch the SG-II and be amazed at what good MPG my little Kia Soul can actually get.

    [​IMG]

    Of course, that will change some, as the road rises or falls. It's never really flat!

    As I pass I-95, going east, it's all city driving, from there to the end of Rt 40 and then down Rt 1-A to Daytona Beach. But even with all those city miles, the average MPG for my last trip was a very nice 35.9 MPG.

    I try to use as many of the tips I've learned here, to improve my overall mileage, but when I'm at home (I live out in the country, on sand roads) my Soul is a working car.
    She (I call her Gertrude) grades my sand road, skids logs, pulls people out of sand pits and just generally Works for Her Living.

    She even spends a lot of time sitting still, with her engine running.

    [​IMG]

    At the "Old Mud Hole" recently, she had to help a friend with a little JUMP.

    So, when I check my mileage for a tank of gas and it's only in the mid to low 20's, I don't feel bad at all, because I know that she's just doing what I ask of her.
    She's a Working Car and she does it very well.

    The mating of the little 1.6L engine and the six speed AT, is truly a work of art.
    I'm an experienced Gear Jammer, but there's no way I could ever shift a six speed tranny as well as the computer does.

    If anyone can't tell by now that I love my 'Gertrude' they've missed the whole point of this post.

    Wishing y'all a very Happy Thanksgiving!
    The Doctor :cool:
     
  18. The Doctor

    The Doctor Old Dude, New Car

    Addendum:

    I frequent the Kia Soul forum, and when I try to impart a little wisdom about getting good mileage, that I've learned here, and with 55 years of driving experience, you'd think I just brought a cat to a dog show.:biglol:

    I change my oil every 3k miles, come rain or shine, and I use the worlds most expensive oil additive, "Prolong" and I run my tires at a safe but more efficient 42 psi.
    I use the K&N Drop in air filter, because it helps my engine torque up quicker and gives me better performance and a little better MPG. But, I get flamed for that too.

    I might not win on the forum, but I definitely win on the highway.

    Happy Holidays!

    The Doctor :cool:
     

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