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What did I do wrong?

Discussion in 'Prius c Fuel Economy' started by Bentg, Apr 14, 2014.

  1. Bentg

    Bentg Member

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    I recently took a long-ish road trip (300 mi. round). It was 95% highway, but 80% of that very flat. Temp outside was mid-30s to low-40s (F). On the highway, I barely got 40 mpg. In fact, on the way up, the readings on my car said 38 mpg, which probably means even less than that. Most of the highway speeds were 75 mph and I had my CC set.

    What was I doing wrong? Even at 75 mph, shouldn't I get better than high 30s mpg? My car is still very new (hit 1000 on this trip), so does it need to break in a bit? I got 48 mpg with my first tank, and only 41 mpg on this one with the long trip. Is this typical?
     
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  2. Easy Rider

    Easy Rider Active Member

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    Yes probably......to all of your questions.

    The C is optimized for CITY driving. That does not mean 75 MPH.
    Yes it needs to "break in" some.
    Yes your mileage will drop off DRASTICALLY above 60 or so.

    Give it some time and check your mileage in the city or on a trip on 2-lanes at 60-65.
    My long term average (~3000 miles) so far is about 51.....but that includes almost NO time on the freeway above 60. With a little care, I can get ~60 around town or on a leisurely country cruise around 50 MPH.
     
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  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Cold temps are your enemy, speed is your enemy. Cruise Control should be fine if it is dead flat, it is your enemy on hills.

    Bob Wilson did a MPH vs MPG curve for the lift back, for the c the low speeds should be better, (it is a city car) and the high speeds worse (it is a city car)
    [​IMG]

    Notice that it was over 80 degrees out when he tested.
     
  4. Bentg

    Bentg Member

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    According to that chart, 75 was at 50 mpg. So...the C should expect 10 mpg lower than that? EPA estimate is 46 hwy, so what speed does EPA count as highway speed?
     
  5. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    It is too bad you did not read any of the text I wrote. 50 MPG at 82 to 86 degrees will NOT yield 50 MPG at 35 to 45 degrees, even in a liftback. I have no trouble assigning 3/4 to temp and only 1/4 to aerodynamics.

    You may wish to search for grill blocking, or even Engine Block Heaters if desperate. I live in MS, (it was 81 yesterday) so I only grill block about 2 months, in MN grill blocking may be a 6 month strategy with EBH for 3 months each winter.

    Fuel Economy Top 10 Tips in order of % effectiveness? | PriusChat

    Engine Block Heater for 2012-2014 Toyota Prius c - PriusChat Shop

    The traditional EPA test never exceeds 58 MPH, a 2008 enhancement, which the automakers could ignore until 2012, adds a 80 MPH burst.
    The Truth About EPA City / Highway MPG Estimates - Feature - Car and Driver

    Here is a Gen 1 owners month by month MPG in MN

    http://john1701a.com/prius/documents/Prius-2001_MPG_Graphs_Lifetime.pdf
     
  6. Bentg

    Bentg Member

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    I actually read all of it. Thanks for the attitude, though. It was definitely needed.

    FUN TIMES!
     
  7. bisco

    bisco cookie crumbler

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    wind and elevation come into play, and tyre pressure as well.
     
  8. fuzzy1

    fuzzy1 Senior Member

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  9. PriusC_Commuter

    PriusC_Commuter Active Member

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    The Prius is not a magical creature that just gets 50mpg right off the bat. It takes a little bit of a learning curve to get higher mpg with it, and as you drive your car more you'll learn how to optimize the mileage, if you care to. Yes, it takes driving it a little more laid back than you would a car meant for speed. My coworker traded in his Mustang for a Prius a few months ago, and gets consistently 46 mpg, but drives it almost like he used to drive his Mustang leaving it in PWR mode all the time. He doesn't care because 46 mpg >>> 16 mpg which is what he was getting with his Mustang.

    You might want to check your tire pressure, maybe it's a bit low. The temperature makes a huge difference too, especially in the C, as it's battery is smaller it's not as efficient as it will be in the summer. Once you get up to 60s and 70s you'll notice a big difference. Do you have the heater on? The heater is drain on mpg. As stated in previous posts highway speeds aren't as efficient for the C as well (the C does stand for City after all). Try driving 65mph and see if you notice a difference as well.

    Another thing about the Prius I did not know about when I got my first one is that the engine needs to warm up before it can switch to EV. This warm up is almost like a penalty for shorter trips, especially in cold weather, as gas is wasted heating up the engine at the beginning of your ride.

    Try not to get too frustrated with it, and good luck getting your mpg up in the future! Alternatively, accept that you're getting much better mpg than your previous ride (I assume) and just drive it as you would any other car.
     
  10. The Electric Me

    The Electric Me Go Speed Go!

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    Well you only have 1000 miles on the vehicle as a whole.

    One thing I have said in other threads to other new Prius owners, is don't worry or evaluate based on single trips, or even singular tanks. You've got to look at your average...maybe on a monthly basis, and over a longer period of time.

    So far you have one tank at 48 mpg...pretty good. And one tank at 41? And I'm assuming those are your first two tanks?

    Almost look at it from a medical/illness standpoint. If your Prius really is "sick" and has a problem? It won't get better, and the symptoms (poor gas mileage) will become undeniable. Then you will know...

    At this point, with only two tanks, and 1000 miles, you just can't say. I'd expect you are fine and everything is "normal" but I also think you should expect better than 41 mpg gallon on average.

    So just keep driving. And pay attention. See what your average is after your 4th tank and at 2000, 2500 miles.

    If your overall average is still hovering in the very low 40's..then I think you can start to worry. I wouldn't at this point.
     
  11. Bentg

    Bentg Member

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    The problem with this is that I can't drive it as I would any other car because it's much wimpier than most any other car. I knew that would be the case going in, but my way of thinking was the tradeoff would be awesome gas mileage. If I'm not even breaking 40mpg on a long, flat trip where nothing else changes from my typical driving except that my speed is increased, consider me sad.
     
  12. fuzzy1

    fuzzy1 Senior Member

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    ????

    Wimpy? Only by the standards of the 1990s and early 2000s Horsepower Wars. As another poster repeatedly stated, a Prius as all the power an adult needs, but not all the power a boy could want.

    Did you ever spend any time driving cars built in the decade or two after the 1970's energy shortages? My Prius would blow the doors off my '84 2.3L Mustang, which still had all the power I needed.
     
  13. Easy Rider

    Easy Rider Active Member

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    I'm sorry you are sad......but did you notice the sticker on the window that showed the mileage in the city to be HIGHER than it was on the highway ??
    The C was not intended to get a lot of highway use and certainly not at high speeds.
    If that's what most of your driving IS, then you probably got the wrong car.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    That is really just an artifact of the EPA MPG scale with different empirical fudge factors for city and highway. Don't read too much into it.
    While the highway may not be the ideal niche of the 'c', and it won't get quite the MPG of the liftback at highway speed, it would be harsh and misleading to say that it is not intended for highway use.
     
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  15. Easy Rider

    Easy Rider Active Member

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    The design was optimized for low speed driving, as evidenced by the FACT that most all owners really DO get better mileage in city driving than they do on the freeway.

    And as long as we are nit-picking semantics:
    I did NOT say "it is not intended for highway use"........now did I ??
     
  16. DKTVAV

    DKTVAV Active Member

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    Just like others said just a couple more:

    1. From 20 MPG down to 16 MPG you see only 4 MPG lost (20%). From 50 MPG to 40 MPG you see a big 10 MPG lost but still 20%.

    2. Full loaded passengers and luggage is different than 2 people: how many people in your trip?
     
  17. SageBrush

    SageBrush Senior Member

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    40mpg is low.

    Check tire pressures
    Verify handbrake is off

    Perhaps an unlucky day with the wind?

    If you averaged 75 mph though, a lot of your driving was over 80, and in that case the result would be in range of expected.

    Bob Wilson's chart is a gem. Look what happens at 75 MPH and a 10 MPH headwind.
     
  18. bisco

    bisco cookie crumbler

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    this is the result of an ambiguous epa testing system. i assume you are a young person, who up until now, was ignorant of this fact. learning the hard way is always difficult, i hope you can get past it. unfortunately, every now and then, someone will post here with an "i never expected this with a prius" complaint, and go on to trade it in, taking a bigger hit than the lost mpg's might cost.
     
  19. fuzzy1

    fuzzy1 Senior Member

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    That, and the EPA MPG inversion between highway and city, are no different than other versions of Prii. Many drivers see this result, but not all do.
    I felt that was a reasonable paraphrase of your full sentence: "The C was not intended to get a lot of highway use and certainly not at high speeds."

    Yes, the highway is not its ideal niche. But the 'not intended' phrase is often common vernacular for 'should not be used for', even if formal English doesn't produce the same meaning. This is where I disagree. If the 'c' is a better fit to a car buyer's budget, parking space, style preference and cargo load than is a regular Liftback, there should be nothing wrong with putting into 100% Highway service.
     
  20. Easy Rider

    Easy Rider Active Member

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    I don't think your "paraphrase" was reasonable at all.

    And if one decides to put it into mostly highway service AND AT HIGH SPEEDS, they should not be complaining about the poor gas mileage.

    THAT is the only thing "wrong" with that decision. They probably could get similar mileage out of something else with a tiny gas only engine and pay less for it up front.
     
  21. SageBrush

    SageBrush Senior Member

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    The Prius 'C' will get very respectable (as in better than any other non hybrid) highway MPG at 70 MPH. So while truly unreal MPG is a city phenomenon, we should avoid inadvertently adding to the idea that the Prius is not a good highway car. It is in fact a very impressive highway car.

    I'm not trying to pick on anybody, I just want to encourage useful feedback for the OP.