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Why are MPG's all over the place?

Discussion in 'Gen 3 Prius Fuel Economy' started by sshaw10, Aug 4, 2009.

  1. sshaw10

    sshaw10 Member

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    I'm buying a Prius this year solely because of the mileage. I keep reading threads about people getting in the 30's and others in the 60's. How can anyone average 35, even if you're abusing the gas pedal? What kind of driving does the government do to test the car and come up with 50? I could understand if one driver does better with various techniques to get higher MPG but i don't understand how there can be a difference of 30 MPG, that's crazy. Should I expect to get 50 MPG as an average driver? If I got anything less than low 40's I'd return the car as a lemon.
     
  2. tumbleweed

    tumbleweed Senior Member

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    The two big reasons are driving styles and geography. Some people really put every ounce of effort they can into getting the best mileage; others just drive the Prius like they did their previous non-hybrid.

    Where you do most of your driving counts for quite a bit too. I'm fortunate enough to live in a place where there is little traffic and a lot of two lane country roads with 50 and 55 MPH speed limits. So I can get pretty good mileage without having to try quite as hard as folks that live in the middle of a big city.

    Some of us use rather high tire pressures and that help quite a bit also. Other factors might include using a block heater in the winter, percentage of alcohol in the gasoline, etc.

    EPA mileage estimates are determined by letting a computer drive the vehicle on a dynamometer. Then they factor in CD, weight, etc. to get a number.

    How Vehicles Are Tested
     
  3. 32kcolors

    32kcolors Senior Member

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    I'm getting around 50 MPG. I'm pretty sure it can get 35 MPG with abuse.
     
  4. morpheusx

    morpheusx Professor Chaos

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    We have a generation 2 and my wife could careless whatsoever about the gas mileage and she still manages to get 50+ MPG when she takes the car for a few days. Her style is just a tad on the aggressive side.
     
  5. bac

    bac Active Member

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    I can't understand how anyone under any situation (lacking 27 2 minutes trips/day) could manage to get such poor mileage. No matter how hard I drive my Prius, I can't get below 45mpg, and my average after over 17,000 miles is well over 50mpg.

    I attribute much of the talk to trolls.

    ... Brad
     
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  6. blippo

    blippo New Member

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    Short trips puts a hurting on gas mileage
     
  7. AlPrius

    AlPrius New Member

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    I'm sure this is a stupid question but why do short trips kill the gas mileage? I thought that the mileage is supposed to be higher in the city than on highway. I guess to me I equate city driving with shorter trips, but maybe it's the the lack of warm up period on a short trip that kills the mileage?
     
  8. nineinchnail1024

    nineinchnail1024 New Member

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    I tried my hardest to get my fuel economy to go as low as possible, just to see how far down I could push it, and I barely got below 40mpg. Check my thread in the 2010 mileage forums. It's titled something like "How low can I get my fuel economy to go".
     
  9. nineinchnail1024

    nineinchnail1024 New Member

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    Close. It's that on short trips, all of the driving is done during the warm up period. With the ICE running, it's hard to get good mileage.
     
  10. sshaw10

    sshaw10 Member

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    I'm with you, I thought short trips and city driving was where the Prius shined. Up a few posts someone else says driving in a city makes it harder to get good MPG. :confused:
     
  11. FLP

    FLP Junior Member

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    That's me, as well. I live and work nearby, ergo not great mileage, so far. On the weekend I do better when I venture outside of my home radius. I still love the car, but don't expect to see 50 mpg in my future :(
     
  12. FLP

    FLP Junior Member

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    It still is much better mileage than I ever saw in my previous car.
     
  13. Leadfoot

    Leadfoot Penny pincher

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    Three factors mentioned within this thread contribute to my "disappointing" low-40's mpg:
    1. We live in a hilly area.
    2. My wife makes numerous short trips, often starting each leg with a cold engine.
    3. My wife is the main driver and lacks any sort of competitive nature to improve her mpg's (picture her rarely coasting, even heading downhill, and always running the A/C.

    Nevertheless, we are content with the mileage and know we could hit the 50's. With me driving, of course! ;-)
     
  14. ksstathead

    ksstathead Active Member

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    Driving on a cold engine (warm up period) destroys fuel economy. That's one reason some people get horrible mileage vs. EPA IN ANY CAR.

    The other big thing is racing from stop to stop with all the other cars which is a city thing if you choose to drive like that. Driven smartly in the city, the Prius really does shine (once warm).

    Steady mpg max's out around 20 mph, and largely falls linearly with speed. Think of 100 mpg at low 20s mph, maybe 30 mpg at 100 mph (not actual, just for an idea). BobWilson4web and others have posted nice charts of this.

    Conserve momentum by learning to glide and anticipate stops. Press up the tires. Reap big rewards.
     
  15. a64pilot

    a64pilot Active Member

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    I get around 60 because it's fun. We have had the car for a little over a week now. When I was gone on a trip, my wife got 44, just drove it like her other cars. I showed her the HSI, and today on a 70 mile day, she got 53.
    My first 5 min. consumption bar is always terrible, so I can see how your mileage would be terrible if you drove mostly 5 min. trips.
    If you drive mostly 5 min trips, I don't think a hybrid is warrantied though
     
  16. ksstathead

    ksstathead Active Member

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    Warm up is more noticeable in a Prius for 3 reasons: 1) "normal" is so high that the hit you take while cold is larger, 2) the displays show you the hard truth where most cars do not, and 3) Prius is very much about reducing emissions, and it sacrifices mpg during warmup to reduce overall emissions.

    Given a top sniper rifle, I still couldn't make the elite shots for various reasons (training, skill, conditions). It's not the fault of the rifle. Prius is such a tool, and to get the most from it requires something from the driver and the right conditions.
     
  17. nerfer

    nerfer A young senior member

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    It's the commute (distance, speed) and weather for the big factors, then comes tire pressure and driving style.

    I generally get in the mid-50's in the summer, in the low 40's in the winter. I have a short commute so in the summer I bike more. The warm weather plus only using it on longer drives raises the mpg, and in the winter all the cold short trips (about 3 miles each way) really hurt it.

    I keep the tires at 40/38, drive with pulse & glide (monitoring it with a ScanGauge) and do the other things to try to optimize my mileage (grill block, anticipate stops, etc.). I rarely go above 60 mph so that helps.

    I got down to the high 30's this past winter on one tank, but it was colder than normal (highs in single digits, fahrenheit) and I had a problem with the thermos coolant pump, so the engine had to start cold every time.
     
  18. tm2913

    tm2913 New Member

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    I can understand the low MPG. After the test drive, I think it was close to 25 mpg. Accelerated like a regular car every time. Accelerated to 70 MPH on freeway. Then learning to drive a hybrid for MPG takes a little time (this is my first hybrid). I've got the mpg up to 50 now (still on first half tank of gas). Wanting to get good MPG and driving for good MPG are the keys. As others have stated, regardless of whether you are driving a clean diesel, Yaris or hybrid, if you exercise poor mpg driving habits, you are going to get poor mpg.

    As evidenced by my short test drive, it is possible to get "poor" mpg in a short loop. I think I can average 55 - 60 mpg while accelerating fast enough to not tick people off.
     
  19. E Todd

    E Todd New Member

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    We've had our Gen II since May. We've had a cool Summer here in Wisconsin...........haven't used the AC hardly at all, maybe 4 or 5 days. Our MFD consistantly shows about 30-35 MPG during the first five minutes of driving. After that, it dramatically improves. With 1500 miles on the car we're getting 57.5 MPG, which I think is phenomenal. Our trips typically are around 10 - 20 miles in length, so the ICE gets warmed up, the battery gets charged up and we can do some coasting and driving on only the electric motor. It's great fun watching the Energy screen and trying to improve the mileage. Toyota has made great cars for decades and the Prius is like frosting on the cake.
     
  20. wfolta

    wfolta Active Member

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    They are confused: city driving and short trips are two different things.

    There are different kinds of city driving, though, with some providing more room for maneuver than others. Personally, I get good mileage in the city and in traffic jams on the local interstate. But if I were in a traffic jam where traffic crept along at 3 mph for a couple of miles, that would mess up mileage.

    Some people may confound the two: they live in a city and all their driving is short distances. But it's short distances that really do it.

    For example, driving our Prius from the parking space to the garage door (up two floors) is 2/10 of a mile, during which I get 15 MPG: warming up, not able to gather any speed, all uphill. It takes several miles to make up for that poor start.