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How do I get high MPG?

Discussion in 'Gen 3 Prius Fuel Economy' started by priusfella, Dec 8, 2011.

  1. priusfella

    priusfella New Member

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    I don't understand how so many of you guys are getting 55 or even 70 MPG. I drive conservatively and am consistently getting 48 MPG. I drive a mix of city and highway driving. I drive at or below the speed limit. Even at 55 MPH on the highway I'm only getting around 50 MPG. Any suggestions?
     
  2. rogerv

    rogerv Senior Member

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    One major factor is tire pressure. You can inflate the tires to the maximum cold psi shown on the sidewall safely. Check them at least once a month. For the Prius Toyota suggests 2 psi higher in the front than the rear. The owners who are getting in the 60+ mpg are most likely hypermilers, using some fairly extreme techniques. Cold temps bring the mileage down.
     
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  3. spiderman

    spiderman wretched

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    Fill out the questionnaire (sticky) and that will give everyone a better idea of the situation.
     
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  4. Maine Pilot

    Maine Pilot Senior Member

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    I've tried hypermilling and found that it's a lot of work. Also, you're constantly monitoring the HSI display instead of concentrating on traffic conditions--a very unsafe practice. I'm sure the hypermillers will chime in here and say it's a piece of cake, but for me, it just isn't worth the extra effort and being oblivious to the road & traffic, just to gain bragging rights of higher MPG's.

    You have no right to feel "inadequate" when you're getting 48-50 MPG--remember what you got with your former car?
     
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  5. fotomoto

    fotomoto Senior Member

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    Surfside Beach=wind and lots of it. Having just completed my first years ownership here along the gulf coast, I can tell you first hand our (nearly) constant offshore breezes kill mileage; especially highway, I've seen as low as 30mpg over 30 mile legs into stiff headwinds.

    Our short winter, with both its cooler temps and calmer winds, give me my best FE. I got 54mpg on my last tank but my current tank with this cold snap have dropped it back down to 47mpg.

    Take mpg figures with a BIG grain of salt as few post their speed avg too.
     
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  6. bisco

    bisco cookie crumbler

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    what's a cold snap in texas like?
     
  7. fotomoto

    fotomoto Senior Member

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    Well I know we never mention this <grin> but Texas is a big state so it depends on where you are. Up in the panhandle, they have "real" winters but down here freezing temps and/or ice are a super big deal. :p This recent cold snap had overnight lows in the 30's with highs in the upper 40's but it will be back in the 70's in a few days (whew). Needless to say, no grill blocking down here.
     
  8. priusfella

    priusfella New Member

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    - Have you read This Thead Yet? Just did good info.

    - What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations) 48 trip computer

    - What fuel economy are you expecting and why? 50 but when I read post saying 60 70 mpg I get jealous.

    - What are the approximate outside air temps? 50 F

    - How long are your trips? 10 to 30 miles

    How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here) 1 year not sure how to check.

    Have you had your alignment checked? Any pulling or abnormal tire wear? Have not had it checked but seems fine.

    - How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving?
    Equal city/highway avg speed 29. A little stop and go but not much.
    - What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.) mostly flat but a few big hills.

    - What are your tire pressures? They were all in the low 30s but just filled to the correct psi

    - Is your oil overfilled? (i.e. above the full mark on the dipstick)

    - Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.) 2000 Ford Focus I4 manual. 25 mpg

    - What region/state are you in? (if you haven't set your location) coast of Texas

    - How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking? Electric as much as possible soft long breaking.

    - What modes are you using, if any? "normal", EV, power, eco? ECO

    - Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on? NO

    - Are you driving using D or B mode? D

    - HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? Both, auto, mid 70

    - Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15). Yes 15s

    - If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute?

    I welcome feedback about these questions and the length of the questionnaire. Please post your comments (NOT questions about your fuel economy situation) at proposal for mandatory/copy & paste fuel economy questionnaire
     
  9. F8L

    F8L Protecting Habitat & AG Lands

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    Hypermiling makes you even more aware of traffic because you must react early to changing conditions for max mpg.
     
  10. bisco

    bisco cookie crumbler

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    "electric as long as possible" there's your problem right there, a real mileage killer. try to drive without using gas or electric.
     
  11. walter Lee

    walter Lee Hypermiling Padawan

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    You should be able to get 55 mpg on the highway as long as you driving under 62 mph. If I were to make an educated guess - I would say that you are probably driving at or below the speed limit but your top speed limit is likely 75 mph.;)

    btw - I'm a hypermiler novice ( 18 months, 17700 miles, 2010 Prius, overall Fuel efficiency of 61 mpg). My mileage log is under "HyperDrive 1" at Cleanmpg.com. My mpg drops in the winter ( as low as 52 mpg) and rises in the summer ( as high as 70 mpg).

    I have my tire pressure set slightly higher than most (50 psi front/ 48 psi rear, max sidewall 44psi ). Warning = If you are going over 55 mph - then you should not go over the max tire pressure like me. Inflating by 6 psi over the max sidewall pressure rating can be done safely because I am driving under 55 mph, normally I'm driving between 30mph to 45 mph, and my area doesn't have excessive crosswinds (e.g. >20 mph head winds).

    When the driving temps dropped below 55 F, I started grill blocking (100% lower grill intake, 0% upper grill intake). If you are driving on the superhighway longer than 30 minutes and you don't have a temperature gauge then grill blocking is not advisable.

    I monitor the Prius using ScangaugeII (Fwt, SoC, RPM, GPH), when I am using the gas engine I try to keep the GPH between somewhere between .80 to 1.20 (1.5kwh output level) with the RPM somewhere between 1200 to 1600 RPM. This is an efficient operating range for the Prius ICE. From a cold start, I try to get the FwT up to 140F asap and once the FWT is at around 180F - I try to keep it there. I try to keep the SoC over 50% (4 bars on the SOC display).

    Normally, the windows are rolled up, AC is off, Heater is off, and the defroster is used very sparingly. The radio/CD is off.

    I accelerate slower that most people and often my target speed is from 25 mph to 40 mph. I am in ECO all the time because I have a lead foot by nature. I 've planned my route so that I don't have to drive too fast and don't have to stop too often. Traffic lights are better than stop signs because I can sometimes avoid stopping by timing the Prius to the lights. To achieve this kind of Fuel efficiency - I need more time to travel than most - about 25% more time. The longer the Prius ICE is on the more fuel efficient it becomes - my commute is 16 miles by the time I've travelled about 8 miles my fuel efficiency is about 50mpg most of the time. After its fully warmed up - and I if I'm luckly - between the 8th and 12th mile I can push the FE up to 60 mpg - and between the 13th to 16th mile I can push the FE up to as high as 80 mpg for that trip. However, if I'm only going about 1/2 mile down the road to the grocery store and then back home, the FE is about 15 to 25 mpg. IF YOU ARE ALWAYS IN A RUSH TO GET SOMEWHERE THEN HYPERMILING WILL PROBABLY WORK AGAINST YOU.

    For over the last 18 months I have been trying to learn how to hypermile (Drive Without Brakes, Driving with Load, Pulse and Glide, warmup Pulse and Glide, SuperHighway Mode, Steath Warp Mode, ridge riding, etc). Hypermiling requires that the driver stay totally focus on driving - or it doesn't work. At speeds > 60 mph, driving with load is the most important hypermiling technique to master.

    For non hypermilers(given that your tire's max sidewall pressure is 44 psi), set your tire pressure to 42 psi front and 40 psi rear, set the trip B odeometer to zero, get on the superhighway and set your cruise control to 55 mph, and drive for over 60 minutes. After driving for one hour on the superhighway (55 miles), your trip B odeometer should say you are getting about 60mpg but calculated you should get about 57 mpg using E10 in the summer time.


    hope this helps

    Walter Lee
    Cleanmpg.com "HyperDrive 1"
    2010 Toyota Prius III, Blue Ribbon/dark grey, oem floormat
    Yokohama Avid S33 (50/48)
    scangaugeII (FwT, SoC, RPM, GPH)
    100%grill blocking (100% top, 100% bottom)
    Odeometer = +17800 miles, overall 61 mpg
    last tank (12/8/11) = 636 miles/ 10.0gallons/63.6 mpg/E10RFG
     
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  12. priusfella

    priusfella New Member

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    What is driving with load, warmup pulse and glide, super highway mode, stealth warp mode, ridge riding? Also my max highway speed is 65. With most highway driving 55.
     
  13. cycledrum

    cycledrum PSOCSOASP

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    I'm having a tough time staying over 53 mpg on gage. Temps dropped in last week and I've had a lot of < 10 minute trips. I'm 1/2 psi over stock right now.

    Never seen anything near 70 mpg steadily in a Prius. Seen 55 with longer trips and warmer weather.

    I might go up to about 38/36 on tires soon, see how that feels.
     
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  14. walter Lee

    walter Lee Hypermiling Padawan

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    The HSI display is just a learning/feedback device - a hypermiler isn't suppose to constantly
    monitoring the HSI display or the ScangaugeII (if you have it). Most of a hypermiler attention goes to monitoring traffic conditions to determine which hypermiling technique is applicable/doable.

    My preliminary results suggest that hypermiling can increase FE by 20%.
     
  15. walter Lee

    walter Lee Hypermiling Padawan

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    You should either watch the video link on the PriusChat sticky or go to Cleanmpg.com (and read the FAQs there ) if you want to know more about hypermiling. (BTW: since one is often exposed to longer periods of sunlight when hypermiling - I put on sunscreen especially design for the face before driving)

    If you set your tire pressure to 42 psi front, 40 psi rear, then set your cruise control (CC) to 65 mph THEN the Prius should get about 52 mpg if its driven for over 45 minutes. Wind resistant from high speeds decreases the Prius' fuel efficiency. To get higher Fuel efficiency, lower your CC setting to 53 mph; at that speed the Prius gets about 64 mpg (calculated, MFD = 68 mpg, but you need to drive over 45 minutes most of the time) .

    hope this helps
     
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  16. priusfella

    priusfella New Member

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    I don't understand how electric is a mileage killer. My mpg indicator goes up to 100 when I'm all electric?
     
  17. cwerdna

    cwerdna Senior Member

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    DWL and RR are covered at Beating the EPA - The Why’s and How to Hypermile - CleanMPG Forums.

    As background about SHM, see http://priuschat.com/forums/gen-ii-...-ugh-what-exactly-super-highway-mode-shm.html. But, that's a Gen 2 thread and I don't know how to know parameters needed for SHM on Gen 3 since I don't have one.
     
  18. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    Hybrid 101: charge in your battery comes from your engine burning fuel.

    So in a hybrid:
    EV: gasoline -> engine -> motor -> inverter -> battery [store for later] -> inverter -> motor -> wheels
    ICE: gasoline -> engine -> wheels

    Essentially, for use of the motor to be better it has to operate efficiently and be displacing inefficient use of the engine, so that the car can overcome the conversion losses. That generally means at times low demand when it only takes a little energy to move the car and it can use a motor and turn off the engine. If you're trying hard to keep it in EV mode (e.g. just left of the center in the HSI) that generally means it would be more efficient to turn the engine on.

    In fact, the most efficient way of driving the Prius is pulse and glide* below 45 mph with absolutely no use of the battery: engine runs to accelerate (pulse) and then with a light touch on the gas pedal you move with the engine off and draw no charge from the battery (glide).

    But, you can't always pulse and glide, and the hybrid system provides the next best thing.
    - It allows the Prius engine to run in a way that favors efficiency over power as electric assist can be used on the rare occasion that there's really high demand. In fact, it's this that makes the maximum efficiency of the Prius much higher than other cars.
    - It allows the engine to be completely shut down when it would otherwise be consuming excessive fuel just to idle and provide a little torque.
    - It allows small amounts of motor assist to be added to the engine output so that the engine runs steadily and efficiently when it is on.
    - It allows energy that would otherwise be wasted to be recaptured using regenerative braking.

    * Pulse and glide is in fact the most efficient way of driving manual transmission vehicles. It doesn't work with most automatics because of inefficiency of the transmission during acceleration.
     
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  19. sidecar

    sidecar Member

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    All I look after is tyre pressures, and mine are not as high as some here (41-40 psi) and I glide a bit. My driving environment is a mix of small towns, country roads, some twisty some straight. Temps here average higher

    Gliding is not going throttle off down hill, just give the slightest pressure on the pedal and you will feel the car fee up a little going downhill

    The very best advice I read here (and I cant remember who it was) was 'drive like you haven't any brakes', this keeps you from braking too much and too often, and makes you a smoother driver. Brakes waste fuel

    mileage converter - MetroMPG.com
    4.2 L/100km, 23.81 km/ L, 56 MPG (US), 67.26 MPG (Imp).
     
  20. NYPrius1

    NYPrius1 Active Member

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    As for MPG
    1 Drive the speed limit.
    2 Drive like u have no brakes.
    3 Learn to anticipate stops and slowing ahead.
    4 Tries at 42/40 PSI.
    Best of Luck to You!