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Driving tips for best gas mileage

Discussion in 'Gen 2 Prius Main Forum' started by MechBob, Jul 8, 2005.

  1. MechBob

    MechBob New Member

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    Just picked up my Prius on Saturday. Have driven 150+ miles. For the first 100, I averaged 40.8 mpg according to the screen. I'm only driving 4.5 miles each way to work plus some other around town driving. I had hoped to get into at least the upper 40's if not into the 50's in terms of mpg.

    I try not accelerate too fast. If I accelerate any slower, I'd be honking the horn at myself for going too slow.

    Any driving tips or comments to maximize mpg will be helpful. Otherwise, I'm thrilled with the car and the envy of everyone at work. They call it Bob's spaceship.

    Thanks for any suggestions!
     
  2. ajturner

    ajturner New Member

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    Congrats! I actually just picked up mine on Monday as well (the dealer had 3 available on the lot!) and have driven the same. A couple of points that I've heard/learned:

    1) It will take a little while for the car to "break-in", approx 2-3k miles
    2) I've found getting up to speed at a reasonable acceleration, but then maintaining that, around 60-65 on the highway, gets me the best highway MPG (currently around 45-50). Also, no hard turning/swerving, as this increases your tire resistance and therefore lowers your mileage.
    3) The limited city driving I've done (to/from the freeway) I'm getting 60-70mpg (sometimes the 5min interval histroy has shown 100mpg!) just by trying smooth accelerations.

    I'm looking for more tips as well - and will post anything else I figure out along the way.
     
  3. Marlin

    Marlin New Member

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    The one thing that would improve your mpg the most would be to move another 15 miles further away from work, but that would be a bit self-defeating.

    The Prius gets what we consider to be poor gas milage (but is actually quite good compared to other cars) for the first 5 to 10 minutes of driving when cold. The car actually purposely operates less effeciently in order to warm up the engine. Therefore if you are lucky and don't have a lot of stop signs and red lights for your first five minutes, you might get around 35 mph. For the second 5 minute block of my commute, where I'm cruising at 40 mph with no stops, I get near 50 mpg. After that I usually get 60 mpg or more.

    It's the short trips that kill you mpg. It's a little disheartening, especially on the first 100 miles or so of a tank when the average fluctuates the most. I can get to work after 30 minutes of commuting with a mpg of 57 mpg or more, and then a couple of 1-2 mile trips during the work day will slam it back down to around 46 mpg. Then my commute home and back to work might get it back up to 54 mpg, only to drop down to 48 mpg the next day at lunch time. It will eventually level out at around 50 at the end of the tank.

    So, for your short commute, 40 mpg is about all that you can expect. With careful driving and perhaps limiting or eliminating lunch trips, you might be able to get 45 mpg.
     
  4. efusco

    efusco Moderator Emeritus
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    4.5 miles, on the right roads/speeds is adequate for mileage in the mid to upper 50s in the summer. My kids' daycare is only about 3.5 miles from my house and I can get in the 60s with this warm summer weather.

    But I've got well over 25k miles of experience, a broken in car, and have a route that requires a maximum of 3-4 stops on a bad day and a maximum speed of 45mph.

    YMMV.

    As mentioned, don't baby the acceleration, there's no advantage and you're probably being less efficient by doing that. Briskly accelerate up to 30-40mph, then back off a bit until you reach cruise speed.

    Anticipate stops and keep a longer following distance than you're probably comfortable with. Don't accelerate to a light. As soon as you know you can't make it through the green light take your foot off the pedal and maybe even add a little light braking. I often go into a 'glide' if I'm not sure if I'll make it or not, but that's Prius driving 401.

    Just realize that if your foot is on the 'gas' you're costing yourself mpg. So any time it's reasonable to be off the gas get off of it. Also, if you can avoid coming to a complete stop and maintain a little momentum that's good too. IOW, if you see a line of cars stopped at a light 1/2 mile ahead start slowing down...you probably have a decent sense of the timing of the lights and traffic along your regular route...as you approach hopefully the light will change and the line of traffic will begin moving and you'll never need to completely stop...that's a bonus.

    150 mile is nothing and you'll definately improve. Take a look at my lifetime numbers for some idea of what kind of improvement you can expect (click link in my signature).

    Also, if you REALLY want the deep scoop on mpg read my knowledge base article....
     
  5. Marlin

    Marlin New Member

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    <div class='quotetop'>QUOTE(efusco\";p=\"105384)</div>
    There's no way I'll ever get in the upper 50s for the first 3.5 miles of my commute. I live at the bottom of two long hills, so no matter which way I go, I've got to go uphil. I've got to go from a stop to 50 mph up a fairly steep incline for about the first minute of my commute. During this, I average about 8 mpg just to get up to and keep speed. Then I can cruise for about 15 seconds before I have to stop at a light. An 1/8 of a mile later is another light, followed by yet another light a 1/4 mile later.

    It's a real drag on my mpg and the first 5 minutes will be around 25 mpg.

    Now on my drive home, everything is flat at the beginning, so if I luck out and catch the two lights on green right at the beginning, then my first 5 minutes, if not using the air conditioner, might show as much as 50 mpg. Usually it's more like 35-40 mpg.

    Once I get going, the MFD usually shows well over 50, but the first couple of minutes always drags my mpg down.
     
  6. efusco

    efusco Moderator Emeritus
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    Yea Marlin, notice the "on the right roads/speeds" part of my post. Clearly there are a lot of variables. I'm lucky to live on a rural street. I can actually drive about the first mile at sub-35mph speeds and have one long downhill followed by a long uphill. I usually get about 2-2.5 miles when my first 5 minute bar pops up. In the summer I can usually get that bar in the 40-60mpg range (usually ~40 though). My second 5 minute bar, if it pops up before I shut down to ditch the kids, is usually around 70-75mpg with my mpg in the mid-50 to low 60s range. When traffic is light I can often keep my top speed at around 40mph which really maximizes things. If there are folks behind me I try to stay at the speed limit which means about 2.5 miles of 45mph driving. Belive it or not that makes about a 5mpg difference in my mileage for that short run. If I have to come to full stops for the 3 lights and drive 45mph I'm going to be in the low to mid-50s at best and in the winter usually in the high 40s.
     
  7. catsbox

    catsbox Member

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    There are many hills near where I live, and I do have to make many short trips. I have learned to let the ICE warm up before I hit the road. Seems like idling uses less mpg than trying to warm up and drive at the same time. I have also discovered that when going up a hill, I do better if I accelerate hard for about half way up, then I let off the gas and "coast" or use the battery for the remainder. This really has saved me mpgs. This method allows me to make up the mpgs on the downhill stretches. I also use the cruise control on city streets where there are few lights. It seems that for me the cruise control feathers the gas better than I can. These are lessons learned after about 1500 miles. Good luck and enjoy!
     
  8. Marlin

    Marlin New Member

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    <div class='quotetop'>QUOTE(efusco\";p=\"105394)</div>
    I actually like it when there's heavy traffic on my route. About half of my commute has a speed limit of 45 mph with the rest at 35 or 40. When traffic is light, I feel compelled to go 45, because the road is never empty and there's always one or more cars behind me. (They would rather go 50-55, but they can just stuff it 'cause I'll do the speed limit and no more on that stretch)

    However in heavy traffic, the cars on the road slow down to almost a perfect 40 mph. With a light touch I can use the electric to maintain speed and a good down hill where I have to brake the whole way charges the battery back up.

    It's just the first few mintues of my commute each way and the two 1 mile trips I make at lunch that kill my mpg. (Well, that and anytime my wife drives the car)
     
  9. rflagg

    rflagg Member

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    Also remember, patience is the key with this car. After 30,000 + miles on my prius, the mileage keeps getting better. Yes, there was a decent break in around 5k miles or so, but I seemed to have a significant break in around 28k or so as well. Patience, grasshopper - be open to learning, don't get too upset if your mileage goes way up and down on the first few hundred miles of the tank (imagine saying that for another car!), and also, don't be afraid to try different things. Since your drive to work is consistent, you can make small changes and see how they affect your mpg (accel. faster, for example, on one or two days). While 40 can seem low for this car, especially with some of us getting high 50s, there are a lot of variables, and I'm positive in time you'll be reaching the 50s mark.

    -m.
     
  10. tstreet

    tstreet New Member

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    Does anyone know if the penalty from short trips for the Prius is greater than the penalty for other cars. Also, the average differential from EPA from the Prius seems to be greater than the differential for the Civic Hybrid. Thoughts?
     
  11. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(tstreet\";p=\"105407)</div>
    I don't "know"--that is I don't have facts to back up my suppositions. I suspect it might be, on a percentage basis, a bit greater for the Prius. I suspect that b/c the Prius intentionally burns richer (it's programmed in and I don't think it is so in other cars) during the first few minutes to get the emissions control features up to temperture as quickly as possible. That is, the goal of the first few minutes is not best MPG, but best emissions. Once that goal is achieved it drops back to maximum fuel efficiency mode.

    I think other cars just run at the preset richness no matter if the cat is hot or cold and thus other than being less efficient in the first few minutes due to the ICE being cold it doesn't suffer that pre-programmed penalty of burning richer.

    I could be totally off the mark on this though.

    I don't think I agree with your observation about the Prius being farther off the EPA numbers than the HCH. I exceed the EPA numbers on both HWY and City driving now. I do not know of any formal testing that compares exact routes mpg and then figures how that compared to the EPA numbers.
     
  12. tstreet

    tstreet New Member

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    Efusco:

    If your theory is correct about startup penalty, then wouldn't it follow that differential from EPA would be greater since EPA warms up the car before it does the testing?

    As far as the Honda goes, that's just based on my personal experience so far. Of course, that could just be a function of my driving style and terrain. In any event, need more data and more miles driven.

    The EPA differential would appear to be backed up by greenhybrid.com but then I guess that's inconclusive because they mixed CVT and manual.
     
  13. efusco

    efusco Moderator Emeritus
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    EPA uses a warmed up car for the HWY portion, but a cold car for the City.

    See: http://www.fueleconomy.gov/feg/fe_test_schedules.shtml

    Note, also that EPA's actual testing numbers are adjust downward 10% for City and 22% for highway from what the test drivers actually get on the dynometer.
     
  14. efusco

    efusco Moderator Emeritus
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    While you're looking at that note that the hwy average speed is 48mph in a warmed up vehicle. If you let me drive at a steady speed of 48mph (which is NOT what they do in the EPA tests--the speed varies up as high as 60mph) at 86 degrees with no AC and no stops on I'm going to get mpgs in the 60s EASILY.

    Note that the range of temps they test at is quite large too...68-86 degrees. Using Wayne Brown's simulator I get 68mpg calculated at 68 degrees with no wind, no A/C, and 200lb load. At 86 degrees with all other conditions the same I get 74mpg calculated!! I think those are actually very realistic numbers. Clearly they're better than the EPA's due to a combination of the variation of speed that the EPA does and the downward scaling they do.

    68mpg - 22%(15mpg) = 53mpg pretty darn close to the EPA's official estimate and I don't know what other factors they figure in (i.e. wind speed, weight in vehicle, etc), also, as I said above, the 68mpg estimate assumes steady speed and will be lower due to the variation of speed that occurs during the EPA tests.
     
  15. Sid

    Sid New Member

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    Another Pennsylvanian who got a Prius this past Saturday! Me too!
    I have about a 85-mile round trip a day for work, and according to the Prius, it's averaged 50 MPG! This is a combination of turnpike and local road driving.
     
  16. tbstout2

    tbstout2 Member

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    Evan,

    Your article is the "Holy Grail" for us newbies! I began driving the Prius like I would my old 30MPG Toyota - and was pleased with the 52MPG. After a few miles I started to change my habits - in the wrong direction - by slowly beginning each take off from a dead stop. My MPG dropped to 46!

    I have followed your advice and am now up to 55.9 on my 50 mile commute up I95 from Fredericksburg, VA almost to Washington, D.C. During my "city" driving today I brought this tank up to 58!

    To think, it will only get better once I change the oil to synthetic and break her in a little more.

    Thanks!!

    Ted