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Getting the Most Out of the Toyota Prius: Driving Tips

13

Comments

  • carz89carz89 Posts: 16
    The onboard computer and the "by hand" methods of determining MPG will yield different results for many reasons, but they should be reasonably close, if not for one tank then after many tanks. One reason is the volumetric endpoint at which you decide to stop filling the tank changes from tank to tank. Another reason is that the "by hand" method relies upon the accuracy of both your odometer and the gas pump flow meter, which are both accurate to better than 1%. The car's onboard computer relies upon the accuracy of the odometer and the fuel flowmeter. I haven't found a published accuracy for the fuel flowmeter, but it's probably the least accurate component of the calculation. I'm guessing it can be off by 5% or so. Toyota doesn't use a thousand-dollar flowmeter, so your Prius is stuck with the difficult task of measuring very small volumes of fuel over a period of time.

    Think about this:
    Let's assume, for simplicity, 50 mpg and an average speed of 25 mph. That yields a volumetric flow rate of 0.5 gallons/hour. If your engine is running only half the time, then it's 1 gallon/hour while running. Converting, that's approximately 2 ounces/minute, or 0.036 ounces/second. Using 30 ml/oz and 20 drops/ml, that comes out to 20 drops/second. The computer is constantly computing an instantaneous mpg, then integrating over time. So, small errors in the flow measurement (fractions of a drop) will result in a noticeable error in the calculated MPG readout.

    My Prius computer yields a typical 50 MPG over a full tank, yet my "by hand" method consistently yields about 2.5 MPG lower. I can live with that, especially knowing that my old 1996 RAV4 (2wd, manual shift) got about 22 MPG (downhill, with the wind from behind) ;)
  • gardener3gardener3 Posts: 4
    Thanks for coming back. I'll have to fill up a few more times to check computer and "by hand" readings. It would be good to know what kind of system Toyota uses for measuring use of gas. It is in software which perhaps gets updated/changed with new versions. I'll keep track of gas purchases and this way later get more readings with higher mileage.

    It is interesting to note that your computer reading is higher than your "by hand" method, while mine is the opposite In any case Prius is a great car! :)
  • pathstar1pathstar1 Posts: 1,015
    I believe the Prius uses the fuel injector open times to measure fuel flow. Your mileage is not abnormally low. Try a little more pressure in your tires. I'm getting 48 MPG US, but I don't use the A/C much. I run 40 PSI front and 38 PSI rear.

    The mileage is supposed to improve when the car is "broken in" as well. That can take 10,000 mi or so. Mine is still new as well (not a Touring). Finally, the Touring tires are supposed to drop the mileage a bit, perhaps 5-10%, but are better in wet etc.
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAPosts: 5,896
    If you are a long-term hybrid owner, our Senior Editor, John O'Dell, would love to hear from you! A short email with your maintenance experiences and concerns would be great. Please send to John at jodell@edmunds.com by close of business Wednesday, August 22, 2007. Be sure and include your Forums username.

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  • stevegoldstevegold Posts: 185
    I have a 2004 Prius since 12/30/03. I myself change the oil and oil filter twice a year and the inside air filter once a year. I keep the tire pressure at 40/38 and bring the car to Toyota only for TSB's which are at no charge. The car is great. I get 45+ MPG. On two occasions I had a dead 12V battery, once early in 2004 and again two weeks ago. I must have left something on overnight. My only continuing problem occurs rarely when climbing a long, steep, straight mountain pass, I run out of electric boost after 5 minutes @ 80 MPH. Short or curved passes are not a problem because I can't go that fast and the ICE is adequate. An electric turbo or a big battery with more capacity would solve that infrequent complaint.
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAPosts: 5,896
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  • I have a 2006 model with 22K miles. I'm going on a long vacation, so the car likely won't be used for about 26 days. Is this too long? Manual says one should drive the car for 10 miles or operate for at least 30 minutes once every "several" months.

    I know I've seen posts in the past on this question, but I don't recall the specifics. I do have a friend watching the house that can take the car for a drive if needed, but I don't want him to bother if not necessary.

    Any opinions or experiences??
  • I started out averaging 42mpg on my 2007 Prius. When I complained, I was advised by the Toyota mechanic to use only brand name gas. I did this and it boasted my mpg to 48-49 for about a month, then it dropped to between 32 to 42mpg. I am getting no help from my Toyota dealer or mechanic. With this last fill, I was getting 36mph. I was getting that on my Corrolla!! I always fill at half a tank and never overfill, turn the gas tank cap 3 clicks. What else can I do to get better mph?
  • pathstar1pathstar1 Posts: 1,015
    Well, I doubt that you got that mileage with your Corolla in the winter. You haven't posted where you live (city or area), but cold weather drops the mileage on all cars. We notice it more on Prius because we expect really good mileage, and we have a readout to tell us the good or bad news. I had a rental Suzuki last winter and it only got 19 MPG (this time of year)! It was smaller than a Corolla.

    1. Make sure your tires are inflated properly. I use 40 PSI front and 38 PSI rear. Many use even more. This will noticeably improve mileage. It also improves braking and handling. Including in snow.
    2. Use regular gas. Your mileage may decrease in winter 2-3 MPG due to the ethanol or other oxidizers they put in.
    3. Cold weather is a mileage killer. We just have to live with that. Don't let the car sit idling to warm up. If you drive it warm-up will occur in just a few blocks.
    4. Short trips are a mileage killer. This is especially noticeable with the Prius, as when cold it can't use its' designed in tricks to improve its' mileage. Try to combine trips. As long as the car doesn't cool off between trips mileage won't suffer.
  • I am really surprised that so many words and so much concern are STILL being expressed regarding mileage.

    I have a 2004 with about 34,000 miles on it; I live in MD, just outside of the beltway around D.C.,I am not a particularly gentle driver, and here are my experiences:

    (first, remember that some or all areas of US must change gasolene reformulation for winter and summer conditions - this in turn changes the mpg measurably). I routinely keep the tires at 35 and 33, whatever is stated on the door jamb plate.

    Where and how I drive happens to fall into 2 distinct categories:

    o about 1/3 was at high speed on highways with speed limits of 55 & 65, where I drove about 9 mph over the speed limit, with the air conditioner on most of the time, and the windows closed; the car had 300 pounds of passengers and about the same in luggage; the time of year were generally NOT in the winter, but were in the other 3 seasons.

    - I routinely got between 49 & 51 mpg based on hand calculations. I was and continue to be very pleased.

    o about 2/3 of my driving was what many people wrote to be the worst conditions - short drives of 5 - 15 minutes(maybe up to 30 or 45 minutes, but rarely more), in traffic, stop lights, etc.

    - here I get around 43 [winter] and 46 [non-winter] mpg.

    All in all, I am very pleased. The only two complaints I have are:

    o it is frustrating filling up the gas tank fully - I find that once the auto pump stops the first time, it helps to rock the car back and forth a few times, then fill it up another 1/2 to 1 gal more; and

    o the car (I think it is the tires) is quite noisy at highway speeds, to the point of needing to turn up the radio/CD player quite high in order to hear them. When I get new tires I will look for quieter ones.

    Enjoy the car and don't sweat the gpm so much. :) :)
  • Hello all, hopefully someone can recommend replacement tires for this wonderful (2004) car. I have about 34-35K miles on the original "Integrity - 185/65 R15s. As I wrote above, I have not liked this tire. It is very noisy on highways, and at 35/33# of air pressure, it gives a pretty hard ride on local, bumpy streets.

    Yesterday I called up my Toyota dealer and was surprised to learn that they the Prius comes with either a 185/65 R15 OR a 195/65 R15 tire. Perhaps the 195/65 is what some have written as the "Touring" tire. Here are my questions:

    1) can I put either sized tire on my same (original) rims?

    2) does either size cause a noticeable change in mpg, or noise?

    3) my research (Consumer Reports + various tire sites on the web)seems to indicate that the Yokohama AVID H4 and the Michilin Pilot EXALTO A/5 tires were the best overall (particularly in wet and dry traction, rolling resistance and noise
  • jana6jana6 Posts: 17
    I've found that I have to drive totally different with my Prius to get the best gas mileage. I watch the Energy screen a lot! It is the best way to tell how to drive--the three second delay is a great feedback for all that. I had been told many years ago that, if I lifted up my foot just a smidgen off the gas peddle, the car would go the same speed but I'd use less gas. Now I finally understand that and it does work!

    I do a lot of coasting to stops. I never have had a heavy brake foot and now I'm even lighter! I slow down way before the stop but not enough to get the drivers in back of me ticked off, if you know what I mean.

    Also, now when I'm driving and I notice my speed is too far over the speed limit, I lift my foot totally off the gas peddle rather than just slightly--I love seeing the 99 mpg!

    I do notice that, if I don't pay attention to my driving, I fall back into old habits (not coasting, etc.) and my gas mileage drops.

    I was surprised to see but it is true, gas mileage does drop in the winter.

    I hope this helps some....
  • I am also looking to replace my tires as i had a flat and had to buy whatever inferior tire was available. Costco has a sale on bf goodrich traction t/a T not H and Michelin hydroedge. my concern is about the gas mileage with these tires. did you buy tires yet? does anybody have advice? thank you.
  • pathstar1pathstar1 Posts: 1,015
    You don't say where you are or what kind of tires you want. I put on Nokian WR tires (true all season) and saw NO mileage hit. Big improvement in traction, dry, wet, and snow.
  • tiff_ctiff_c Posts: 531
    You don't say where you are or what kind of tires you want. I put on Nokian WR tires (true all season) and saw NO mileage hit. Big improvement in traction, dry, wet, and snow.

    I've been using Nokian tires for a long time now and just bought a brand new pair for my Civic. Great tires the WR-G2's are the newest of the WR's and they are great! The Prius will be our next car once it's gotten an update and I'd put the Nokians on fro winter over any other tire.
  • I can always tell when the California EPA makes the refiners here in N CA start using the ethanol gas additive to help cut winter pollution: the mileage on my '04 Prius drops from my rest-of-the-year average of about 51.3 to about 48. 6! By the way, only about 3 of us out of the about 10 people I know who have '04 and newer Prius's get over 50mpg. The rest get about 47-48 in the spring, summer and fall.

    I'm having a right rear brake problem. It sometimes grabs when gently braking at very low speeds. At about 5 mph the right rear wheel can lock. I get some help for a few days by stopping the car with the emergency brake a couple of times, and the regular braking system then works. But I'm sure I gotta bring the car in--I can't keep doing the emergency brake bit. It may not be what's helping anyway, just a coincidence. ABS-- I tried to start the car this afternoon, and it wouldn't, and the ABS check light was on. I finally pushed the power OFF, then back on and all was well for this afternoon's trip. The great car has got to go in for a braking system check.
  • I live in the suburbs of nyc. i don't drive far to work, so my mileage in winter is not good if i only go a mile or two. where would i get the nokian wr at the best price? otherwise i think i will get the michelin hydroedge at costco. i like the peace of mind with the road hazard and rotation. thx for answering.
  • tiff_ctiff_c Posts: 531
    I live in the suburbs of nyc. i don't drive far to work, so my mileage in winter is not good if i only go a mile or two. where would i get the nokian wr at the best price?

    Nokian has a website and a toll free # and they will give you the name of all the dealers near you. I get free rotations with my Nokians every 5,000 miles.
    We have had heavy snow, wintry mix, slush and 2" of sleet! My driveway was not plowed so I drove in the sleet with no problems. The Nokian WR is a tire you won't regret buying. If our winter was any worse i would buy Nokian RSi's. I bought those before and they were awesome in snow and ice but terrible on dry pavement.
    The WR's are good in snow and ice and excellent on dry roads.
    http://www.nokiantires.com/en/DEFAULT.ASPX
    This website should help you find your answers.
  • Hi there,
    I just bought my first Prius 3 weeks ago. I love it. I was recently stuck on a typical Southern California freeway for an hour and I became concerned as I watched the battery going down, down, down. When I say stuck, I mean that it took 50 minutes to go about 2 miles. Should I be concerned? Was my mistake that I was watching the "energy" screen? It went down to about 2 bars. Thanks for any help you can give me.
  • You can watch the screen if you'd like. It means little. A full battery gives you 2-3 minutes of power assist, an empty battery requires 2-3 minutes to recharge. A Prius is a well designed small car with an UNDERSIZED engine that uses the battery/motor to assist when you need to accelerate quickly or drive up a short steep hill. That arrangement provides good economy for normal driving (90+% of the time) and good performance for the other 5%. There are a lot more fine points but that's the basic reason you get good economy and good performance. I have a 2004. It is the best car I've ever owned and the most fun. My wife's Highlander Hybrid sucks except it's a 4WD which we need when it storms here in Colorado. Good luck.
  • Thanks very much. I thought I was just obsessing. I absolutely love this car and the advice available in this forum. :)
  • jerry24jerry24 Posts: 3
    i have a 2005 Prius which has not given me any trouble in the 2 1/2 years I have owned it. But I recently had a problem and wonder if anyone can help. I was parked on a steep downhill driveway. When I tried to back uphill the electric motor was not strong enough and nothing happened when I pressed down on the accelerator. I had to keep my left foot on the brake to keep from rolling forward into the garage door. The gas motor finally kicked in after pumping the accelerator a few times. Was I doing something wrong?
  • stevegoldstevegold Posts: 185
    When in reverse, the Prius can only use the electric motor. There is no direct connection between the gasoline engine and the wheels in REVERSE as there is going foward. When you stepped on the gas, the gasoline engine generated a boost of electrical energy to power the electric motor in reverse. It's an interesting situation that I've not run into. (It would be hard to start backing up a steep hill with a manual transmission). I think you did the right thing. I'll ask my Toyota service manager the next time I see him.
  • laurasmithlaurasmith Posts: 1
    I live in the California Sierras at about 4000'. I have a twenty to thirty minute drive to work. I go up about 700', then down 700' on a winding road at an average of 35mph with only a few stops. It does get cold in the winter.

    Does anyone think this typical daily driving falls within the "optimal" range to get 48 mpg? I have read that the optimal range is 30-60 minutes at 35mpg with few stops in warm weather.

    I want to go hybrid, but don't want to waste my time/money!
  • sharon22sharon22 Posts: 28
    I'm wondering the same thing -- I live on a mountain, drive 20 mins. downhill/uphill to work 10 miles away. Rarely drive highway. Will I ever really recoup the expense of a Prius living on a mountain, driving short distances and only once a month (if that) highway miles? I am on a waiting list for pkg. 2, but . . .
  • semenzatosemenzato Posts: 28
    We and our Prius live in the Oakland Hills at about 1000'. Almost every destination (except a nearby grocery store) is at or near sea level, so we go up and down the hill a lot. We still get about 45mpg, with a fair amount of driving in the flats. The hill is steep enough that we use the B gear (engine brake) and typically the battery gets fully charged about 1/2 way down the hill. On the way up we drive at 30mph and 15mpg.

    I think the Prius does quite well with a lot of short ups and downs, and less well with long steady climbs. But we also have an Odyssey, and when I use it for short trips up and down the hill I get 16mpg. I would think just about any car will get worse mpg in the mountains.

    Another data point: when we drive the Prius to Lake Tahoe we get about 40mpg on the way up, and 50mpg on the way down. This includes a long flat stretch between Oakland and Auburn, where the climb begins.
  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAPosts: 5,896
    This discussion is about driving the Prius and getting the most out of it. The posts on battery pack life have been moved to the Toyota Prius Hybrid System Questions discussion and you may continue there.

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  • laughen59laughen59 Posts: 10
    I should be getting my 2008 pkg. 3 next week. Can you explain the B gear, how and when to use it? The dealer didn't explain it well and I don't get it.
    Thank you.
    Barb
  • eprupiseprupis Posts: 30
    The "b" gear is an engine braking gear---similar to a lower gear on a stick shift or automatic. Only use it when descending long, steep hills. The cruise control will be disabled by its use until you restart the car.
  • tommtomm Posts: 31
    Barb - just don't use the B drive - no need and it uses too much gas/engine. Got my '08 3 weeks ago - on a whim - after I saw the golf cart, shoes, hats and clubs fit beautifully, I traded in my luxurious Audi A8 - havn't missed it yet. Averaged 48 MPG since new (a few hundred miles on it when I bought it). I do miss the tilt function on the driver's seat - I feel a bit too pitched forward - but getting used to position.
    Good luck to all those lucky enough to have one - heard they are now selling over sticker - and you can't get one! Tom near Boston
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