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Poor :-( Gas Milage !!!

Discussion in 'Gen 2 Prius Fuel Economy' started by xwinger, Jan 9, 2008.

  1. xwinger

    xwinger xwinger

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    My daily morning commute is about 6 Smiles (I live in the SF Bay Area and I call them smiles because almost everyone else I work with has to fight the dreaded Hwy 4 commute from Antioch / Brentwood to work in Martinez, CA.) I've been reading a lot here and understand that the car MUST warm up firsrt (must be a female :eek:). It is MOSTLY a stop sign and go commute of 6 miles. It does NOT get cold here in the mornings ;). I watch the screen and have figured out how to feather the pedal and I've ALWAYS been a person that does not race up to stop signs. I drive to near the top of a hill and then coast. If I see a stop sign ahead I coast. I use B when going down hill and when my coasting speed (on flat ground) is too fast for the distance I will be travelling. I get this from compression braking on my ST1300 and many years of motorcycle riding.

    Anyone else out there live in Pleasant Hill / Martinez area?

    Any pointers will help.

    Thanks.
     
  2. Codyroo

    Codyroo Senior Member

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    What kind of mileage are you getting? What kind of mileage did your F150 get over the same commute? From what I've read on this site, you don't really want to use "B" unless you are going down a really long grade, so that may help a bit.
     
  3. efusco

    efusco Moderator Emeritus
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    What mileage are you seeing? What's your tire pressure? How many miles have you driven? Have you read my MPG article?
    Oh, and stop using B-mode, it's not helping and may be hurting your fuel economy.
     
  4. Earthling

    Earthling New Member

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    What do you mean by that?

    It gets better mileage after warming up, but to get good mileage you need to warm up while rolling down the road, not sitting in your driveway.

    Harry
     
  5. xwinger

    xwinger xwinger

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    You know, like Fore-Play, Warm Up???
    Just being sarcastic!
    Sorry if I offended you!
     
  6. 524

    524 Guilty but not Responsible

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    I didn't know about the not using brake assist thing, I use it alot! :eek:

    I just don't like being that be-otch on the freeway that always hits her brakes. Guess I'll have to re-adjust the way I drive yet again.

    and winger it sounds like you need to answer the actual mpg question. What are you getting now that you think sucks.
     
  7. nerfer

    nerfer A young senior member

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    Yes, B mode allows engine braking, but that doesn't recover kinetic energy like the regenerative brakes on the wheels do. If you take your foot entirely off the gas pedal, the Prius actually applies a slight regen brake to simulate the slowing down a normal car does when in gear with no gas applied. If you depress the gas pedal a little bit (at least when under 41 mph and a warmed-up engine), then you get into the glide mode, which is much like coasting in neutral in a normal car.
    So if you can plan ahead, you can usually slow down most of what you need by just taking your foot off the gas, except on hills. And really big hills do require B mode, but it reduces your mpg.

    Also keep in mind that since the batteries get their energy from recovered energy, using the batteries to accelerate (engine->wheels->brakes->battery->wheels) is not as efficient as using energy directly from the gas engine. So don't try to start off really slowly to maximize time in battery mode, it doesn't help. The whole idea of the batteries is to provide expected acceleration when combined with the engine. So when you really need it it's there, but from a smaller, more efficient engine.

    Of course, the doctor's reference has more information for this.
     
  8. xwinger

    xwinger xwinger

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    OK. I measured my commute this morning. It's actually 5.3 miles and has 15 stop signs / lights enroute. Terrible way to measure gas mileage. O ly had the car 3 weeks now and have put on 600 or so miles. Will be going to Bakersfield this weekend. Will let you know how she does on monday.
     
  9. efusco

    efusco Moderator Emeritus
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    Yeah, you need to have patience padiwan!
    Your highway trip should give you a lot better idea, your current commute will make it tough to get good FE...it's very short and has a lot of stops...not good at all as it makes it hard to even get warmed up. An engine block heater would definately benefit you...at least on the way to work...if you can plug in at work all the better.
     
  10. ny biker

    ny biker Member

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    My commute is only 4 miles each way with plenty o' stop lights and stop signs. In the summer I was getting 47-48 mpg for these trips (50-55 mpg highway). My worst tank so far this winter (all short trips, no highway driving at all) was 37 mpg. Disappointing but still way better than my old car was getting.

    I have no engine block heater (no outlet available to plug one in), am too mechanically incompetent to block the grill, and pay very little attention to tire pressure. In summer I keep the A/C on and drive with the flow of traffic (i.e., 65-75 mph on highways). In winter I actually don't turn the heat on much because the car usually hasn't warmed up enough before I get to my destination, but on longer trips I do use it.

    All of which is to say, if you do some of the things that can help your gas mileage, like installing the EBH and raising your tire pressure, you will probably be able to eek out decent mileage even with your commute. And whatever you get is still better than you'd get with most other cars.
     
  11. japoust

    japoust New Member

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    I have the exact same situation. I just bought a used 2005 Prius. The first tank of gas gave me about 37 mph. So far, on my second tank I am getting 29 mph. I am sooo disappointed. And I don't know what I am doing differently with this tank than the first.
     
  12. Codyroo

    Codyroo Senior Member

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    Well, knowing what I know about Pleasant Hill and Martinez.....

    Are you taking Alhambra Valley Road or one of the other main streets, or basically cutting through the neighborhoods? I'm going to guess that despite the 5 mile commute, with that many stop signs/lights, you probably take at least 15 minutes to get to your destination. If so, take a look at your first 5 min bars vs the second (and third if you have one) and see how you are doing.

    You'll do yourself a ton of favors if you can coast to the stop signs well in advance of them. Rolling the stop signs will be bad (expensive ticket). Just get back up to speed and ease off the throttle and enjoy the coast to the next stop sign.

    Best of all, once the winter weather leaves, you can ride your bike to work (almost as fast as you drive) and get lots of fresh air, exercise and tons of gas mileage savings! :D
     
  13. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The weekend is coming up. I'd like to suggest an experiment:

    1. Saturday morning - reset the MFD and trip meter
    2. Drive about 2 miles - record the MFD mileage and trip meter miles
    3. Reset MFD and trip meter
    4. Drive about 10-20 miles - record the MFD mileage and trip meter miles
    This exercise will demonstrate the impact of the morning warm-up, even a rolling warm-up.

    Bob Wilson
     
  14. ny biker

    ny biker Member

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    What is the weather like where you live?
     
  15. richard schumacher

    richard schumacher shortbus driver

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    Something is unusual to be getting such (relatively) lousy MPGs. What's the pressure in the tires? Are you certain that the parking brake is completely released? Are all of your trips less than a mile or so? Do you drive it alot shifted in "B"? (Don't!) You're telling us the MPGs reported by the car's display, right?
     
  16. xwinger

    xwinger xwinger

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    HI YA'LL

    Thanks for the advice in the postings. I thought taking my foot OFF the pedal and coasting (with green bars going back the battery) was the "BEST". I've learned that I need to find that "G" spot where the car is totally coasting (no lines appearing on screen). I was actually able to do it. :D It kind of like driving a video :eek: game and trying to beat it. F:DN. I also learned that VERY SLOW take offs from stop signs / lights DOESN"T really work with this car. I've been getting the car up to speed sooner and then making sure I get the lghts going BACK to the battery from the EM. It seems like the gas mileage JUMPS when I can this. I thought it was better to have the EM and the ICE BOTH going towards the front wheels.

    Practice, practice, prcatice,

    I may get a plate "VIDEOGM"
     
  17. xwinger

    xwinger xwinger

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    I live on the border of Pleasant Hill and Pacheco. There are NO places whith long straight aways :( I know i'm doing MUCH better than I did in my F-150.
     
  18. bruceha_2000

    bruceha_2000 Senior Member

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    After you have had it a while, you will see that the car chooses its 'happy place' based on the current conditions: engine temp, battery state, what you are asking of it, etc. On a specific stretch of road, on different days, you might see ICE only, ICE and battery charge, ICE and battery use, battery only. I've seen high 90s MPG at 55 MPH with both ICE and battery driving the wheels. Clearly the ICE is no higher than idle. On a different day, it might be ICE only and 35 MPG. I have also seen 99.9 MPG with battery only doing 65 down a hill on the interstate.

    I've driven I-5 between LA and SF, though not in a Prius. Don't expect great mileage if you are going with the 75+ MPH traffic. At 55 MPH I get over 55 MPG with plenty of up and down hills, nothing special, just set the C.C. (I managed 59.6 for 110 miles a couple of weeks ago). At 65 MPH, it is 10 MPG lower. Have never done 75.

    As far as your daily commute -
    If you can, choose a route that doesn't go down hill just to go back up again.
    If you find a line of cars at a stop sign, stop behind the last car until the engine shuts off (it won't kill the people behind you if you don't move for 7 or 8 seconds, the stop sign isn't going away). Then let the car 'idle' forward on the EM, feathering into glide when appropriate. Try to never hit the brake pedal again until YOU reach the stop sign. If you use the ICE to move forward, it won't shut off again for several seconds and you have blown the basic premise of EV :)

    I don't think you ever did tell what your 'poor' gas mileage was.
     
  19. jiw395

    jiw395 New Member

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    has anybody tried closing off the air intake in the front of the car {winter driving}?? I just did and I got to say my mileage picked up from 43 to 49mpg. I haven't refilled yet, but in 2 days it jumped up great....I used cardboard on the lower grill and foam pipe insulation on the upper grill, doesn't look bad, BUT sure did increase my mpg's. I lve in the midwest area, Indiana and it does get cold here.......:)
     
  20. edthefox5

    edthefox5 Senior Member

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    your kidding right?