Increase the MPG for a 2009 ex-leased prius

Discussion in 'Toyota Prius Family' started by Cats59, Jul 27, 2012.

  1. Cats59

    Cats59 New Member

    I recently (2 months ago) acquired a 2009 ex-leased Prius with 19k on the clock.
    I was very happy with my 35mpg (a vast improvement on my previous 13 yr old cars 18mpg) Until a Prius driving cab driver burst my bubble. He was getting 44mpg in stop and go Los Angeles traffic.
    This friendly cab driver suggested changing the engine air filter (I just ordered a new one on ebay) and changing the oil ( I don't remember which oil he suggested I change it to)

    So my question is, Is it worth getting an oil change? what kind of oil will make the improvement? Is there something that the previous driver was doing that has permanently reduced my MPG?, could there be a problem with the battery?

    I'm a newbie here with hybrids and do not drive vast distances, I never drive on the freeway and mostly drive distances of less than 20 miles.
  2. lxmike

    lxmike Well-Known Member

    Oh Myyy!! My Friend if you do a lil research here and listen to the tips you get here 44 will seem low!!
  3. southerncannuck

    southerncannuck Well-Known Member

    Off hand I doubt that the air filter would make any difference. If you just got the car you might want to change the oil just so you have a known starting point. Poke around this site and you'll pass 50 mpg. Make sure your tire are well inflated, and learn to anticipate having to slow down....and coast.

    Best of luck!
  4. herm

    herm Well-Known Member

    Cats, where do you live?.. perhaps a nearby forum member can give you some tips.
  5. EVuser

    EVuser Well-Known Member

    Welcome. I'm having a hard time believing a Prius only getting 30 something MPG. Do you let it idle a "large" amount of time? Idling with the AC on is going to lower your mpg on anything if you do it long enough. Numerous Prius owners on the forum.:flag:
  6. phoebeisis

    phoebeisis Well-Known Member

    Welcome-Cats59(why cats- have cats-pets??)

    Your 35 mpg-isn't horrible-and many Prius owners get that in pure city driving.
    My wife gets EXACTLY THAT-and worse-in pure short trip-1,2,3,5 mile trips with a cold motor).Like you say-with your current driving style it is DOUBLE what you got with your old car-YOU should be a happy man.
    BUT- with minor changes-you'll get 40mpg-45-50-55-roughly what I get when I mildly hypermile our 2006 Prius-same trips wife gets 35mpg on.

    1)P&G (Pulsing up to speed then lifting easing off accel until both motors off-no yellow no green on screen-then Gliding gliding with both motors off)-with a normal car-like my Suburban-you would take your foot completely off the gas and glide- with a hybrid if you do that the Prius will automatically add some "braking" to regenerate some electrical energy-it will SLOW YOU DOWN-which you don't want. For regular drivers when they lift completely off the gas- it is because they WANT to slow down-so the Prius computer makes that assumption-and starts "catching" some energy that would be lost to heating brake discs. You DON'T want that-you want to use that hard won kinetic energy (1/2 MV^2) to glide as far as possible.
    But why not just accept the regenerated energy- BECAUSE IT IS INEFFICIENT- whenever you change one "form" of energy into another-mechanical>electrical potential energy-you lose a lot of it-usually as heat.

    1)The oil-helps tiny bit-
    Syn oil-many use Mobil 1 5w30- maybe even 5w20(whatever manual says)
    It will help "a little" over plain petroleum oil- but not much-1 mpg at best(others argue that)

    2)Tire pressure-42 psi is sidewall max-Prius are soft riding-so 42 psi is no problem-and not a safety problem.
    The door panel and manual will say 35-36 psi- if you decide to stick with that-make sure you check it COLD-in the AM- check weekly. 42 vs 35 psi is maybe 1 mpg-some say more.

    3)Air filter-doesn't matter- but change it if it is dirty/old-no mpg improvement- but it needs to be serviceable-

    Pulsing and Gliding- slight tire pressure increase-you will be at 40mpg pretty soon if your trips are all short-3 miles-with cold motor.
    With practice-45mpg- 3 mile trips- is likely
    More practice-50 mpg+

    You can certainly get 5mpg better-with P&G and tire pressure-maybe much much better-depends a lot on your cold engine trip distances.
    If your average trip is 1 mile-with a cold motor-35mpg is good.
    Average trip 2 miles cold engine -42 mpg is ok
    Average trip 5 miles-50 mpg
    Average trip 12 miles-55mpg is ok.
    So cold motor-extremely short trips(1 mile extremely short)-are poison for FE.

    I bet you'll get to 45 mpg in a month or two-
    You might get to 55mpg.

    Don't get discouraged- it takes practice-then becomes second nature-doesn't increase trip time more than about 1-3% in city driving(once you learn your route,lights,stops etc-always anticipate stops-and get off gas EARLY-be careful- if you take your foot completely off gas-you regenerate-fine when you WANT to BRAKE- not fine when you want to glide)

    I run on-DON'T DON'T get discouraged when you ead all the folks here who get 50-60 mpg in a Prius in city/suburban driving(and will imply that is NORMAL) take a bit of practice.

    Oh-EXTREMELY UNLIKELY- that anything the previous owner did permanently hurt your MPG.
    You just are beginning a learning curve-you are in for a pleasant surprise.
    Hey let me know about the cats-some cat likers here-lotta dog likers here-I'm both
    But Cats might be Broadway show- Dancer maybe??or something else??
    If this is too personal-ignore me.
    Pulse and Glide-tire pressure(42psi-check weekly)-Mobil 1 5w30-(yes I repeat myself-sorry)
    Last edited: Jul 27, 2012
  7. ALS

    ALS Super Moderator Staff Member

    The other factor that others haven't hit on is your AC use. With the heat we are having plus short trips that can be one of the major factors on your lower fuel mileage.

    There is also a 12V battery that also may be having an effect on your mileage. Most Prius sites recommend changing out the 12 volt battery every three to four years. If that battery starts getting a little weak it can cause the engine to run longer than normal trying to keep it fully charged. If you live in a hot climate it might be prudent to get a new 12 volt.

    Go with the Toyota recommended weight oil and pump those tires up a few pounds. If you like your motor and plan on keeping the car for many more years DO NOT put a K&N filter in your air box. They do not filter as well as a high quality OEM type paper filter.

    Rule one, Do Not get cheap on filters or oil when it comes to your car.
  8. phoebeisis

    phoebeisis Well-Known Member

    Walmart big box stores usually have 5 qt jugs Mobil 1 for $33 or so-
    A "good filter" maybe $7-$11-
    So $40 DIY oil change
    ALS has a point-don't cheap out on oil filter and don't bother with "performance filters"
    You can online ebay or whatever a genuine Toyota air filter for $25-same story on cabin filter-Toyota OEM oil filters are probably $6 on ebay
    Some folks-me-are lazy-and use Mobil 1 Extended change oil so they just change it once a year-8,000 miles-maybe $38 Walmart-I don't think this is the "best way"-probably Mobil 1 regular and 5000 miles is optimal.

    Read all the P&G info on the site-and in 2 weeks you'll be at 40mpg-4 weeks 45mpg-
    watch tire pressure-once a week-at least door 35psi-pressure
  9. diamondlarry

    diamondlarry Super MPG Man/god :D

    Welcome to the site! As you have seen from several here, 35 mpg in a Prius is terrible. I would make sure the tires are at leas to sidewall max;) and, if you get the oil changed, make sure they don't overfill it. The oil level should be in the middle of the range on the dipstick. My son changes the oil at his shop but, I used to just leave them 3 quarts of oil. Overfilling in a Prius can have a serious negative impact on mpg's.
  10. Ophbalance

    Ophbalance Administrator Staff Member

    I'll second the three quart rule. I don't ever need more than that to get the dipstick to half-way. And if you have a BJs near you, they tend to sale Mobil 1 every quarter or so. It usually brings down a case of 6 quarts into the $25 range. I change my own oil as I no longer trust quick lube places in general.

Share This Page