32 MPG average on the last 10 000km

Discussion in 'Gen 2 Prius Fuel Economy' started by morglum, Dec 26, 2014.

  1. morglum

    morglum Junior Member

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    Hi everyone,

    I am getting what appears to be a low fuel economy, as I am getting the same fuel economy using my 2009 Touring Prius (canadian edition) than I was with my old 2005civic. I havent done the total over multiple refills, but every refill I seem to be getting around 32 MPG (7.5L/100km). The in-car display claims I am getting 6.5 L/100 km (37 MPG), but that really doesnt feel right. Also, my Torquqe app instant reading for L/100km are always a good 0.5 L /100 km higher than the onboard display.

    This is the consumption since I bought the car in July (2009 touring at 157 000 km). I live in Canada, so this means frezing temperature at night since early October, and freezing during the day in November. In the summer the onboard display was around 6.2 and slowly made it's way up to 6.5 over Fall.

    Lately, I have driven 2 500 km on te highway at 74 mph and the onboard display has been oscillating between 6.4 and 6.5 L/100km (37 MPG) , so I guess that is what my most recent use is.

    I havent noticed an uneven wear on my summer when I installed them in the fall, but I am very surprised that they will need to be replaced after only 15 000 miles.

    The 12V battery is new from 2013, reads 12.2V without load and 11.2V with load

    - Have you read This Thead Yet? Link is dead, but I think I have in the past.

    - What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations). 37 MPG according to onboard display, 32 MPG according to sporadic calculations from refills

    - What fuel economy are you expecting and why? Please tell me ! :)

    - What are the approximate outside air temps? LAtely it has been between 0C and -10C

    - How long are your trips? It's normally short trip where the car doesnt have the time to warm up completely. However, I just did 5 300 miles trips in the last 2 weeks at 74 mph and the average hasnt moved.

    - 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?

    - What region/state are you in? (if you haven't set your location in your profile) Quebec,Canada

    - What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.). The highway drives are on flat terrain.

    - Is your oil overfilled? (i.e. above the full mark on the dipstick) Dont know, will check

    How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here) . 12.2V no load, 11.2V under load. No driving for the past 3 days.

    Have you had your alignment checked? Any pulling or abnormal tire wear? Not checked, no pulling, wear is even but appears very fast.

    - 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). factory whels, fromt are hankook optimo 4s, back are nokia hkkapelitta RSi,

    - What are your tire pressures? all around 36 PSI

    - 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.) 05 Civic manual. That car would consistenly get 7.5L/100 km on the highway at 74 mph(32 mpg). before that I had a 98 tercel, manual that would consistently get 6.7L/100km on the highway at the same speed.

    - How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking? I am not trying to stay in electric only. I minimize braking and I try to pulse and glide / stealth warp when situation allows.

    - 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 mode.

    - HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? in winter: no AC, auto mode around 23C

    - 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? not that I know off

    Spark plugs may be old. I havent cleaned MAF sensor/throttle body. air filter is new.
    thanks everyone
     
  2. nh7o

    nh7o Off grid since 1980

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    The Prius is sensitive to misalignment, so that is something I would check first. I am not sure if those tires you mention are rated as LRR, but that is a factor if they are not. The car should feel like it coasts very easily compared to normal vehicles, when doing a "no arrows coast" below 66 kmh/40 mph. That is one of the fist things I noticed when I got mine, so if it feels at all sluggish when coasting, something is not right. Was the car ever repaired?

    On flat level road with no wind, at a constant speed of 70-80kmh, you should see closer to 5 l/100 km if all is well.

    Your 12V is probably OK. Just to make sure, your ICE does go on and off and you can access EV mode once the car has fully warmed up, yes? The ICE is not running continuously? The ICE will run more in cold weather to keep the heater going, so fuel economy will go down.
     
  3. fuzzy1

    fuzzy1 Senior Member

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  4. morglum

    morglum Junior Member

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    thanks for replying!
    The car does coast better than any car in front of me when doing the glide part in the pulse and glide.
    The car has had its front bearings repaired, so maybe that caused a misalignment. Again, my summer tires wore very fast, but evenly and without pulling.

    I can get 0.0L/100km when gliding once the car has fully warmed up. In cold weather this can be surprisingly long (20 minutes) but it usually needs around 10. Having the heating on sometime does prevent the ICE shut down even if the ICE is warm.


    I did get around 5L /100km when doing 80 km/h this summer for a whole 500 km trip. That was awesome, so maybe the car isnt doing anything wrong?

    I'll try and have alignment checked anyway ( cheaper than replacing tires every second year!). Is replacing spark plugs useful6
     
  5. morglum

    morglum Junior Member

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    I'm curious though: when on cruise control at 119 km/h (74 mph), my ICe is feeding power to the battery about 90% of the time on flat terrain, is that normal?
    cheers!

    Thanks fuzzy1, i had read that PDF a while ago, but it's definitely worth another read. I am not expecting to beat the EPA, but to at least beat my lead-footed friend with a 2008 prius with an onboard display that says 5.5...
     
  6. nh7o

    nh7o Off grid since 1980

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    Yes. The actual amount of current flow may not be much, however. Just enough to run the various loads. If you want to get an idea of actual quantities of power being moved about, you need to use one of the monitoring methods that use the OBDII port. Torque, Priidash, etc.
     
  7. bisco

    bisco cookie crumbler

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    12.2 volts is pretty weak, and the car could be using some energy trying to keep it charged.
     
  8. bisco

    bisco cookie crumbler

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    74 mph isn't helping. a good base to work from would be a nice long drive in the country at 30-40 mph. if you get up over 40 mpg, everything is probably fine, and a little tweaking here and there might get you close to 50.
     
  9. Blizzard_Persona

    Blizzard_Persona Senior Member

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    Speed limit is 90kph around where you live, ok, maybe it's 100 on route 50, stick to those limits and use cc and watch your number rise.

    Also pump your tires up, 36 psi is doing you no favors.

    Are you blocking your grill? If not look it up and get er done., it will help with keeping the car at a optimal running temp and should warm up quicker. ..It gets cold up there, I should know, I used to live about a half hr from you...
     
    #9 Blizzard_Persona, Dec 27, 2014
    Last edited: Dec 27, 2014
  10. morglum

    morglum Junior Member

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    Hi all, thanks for the replies, very appreciated. I think the take out of this is to increase tire pressure, have my alignment checked and maybe block the grill ( I have Torque to monitor temperature). When these tires die, replace them with LRR tires.

    The car is probably fine, Im just not sure exactly why my lead-footed friend get much better MPG than I do.

    It seems that my car usage is simply one where the prius doesnt do anthing better than my old civic. it's either a 10 minute drive to work (where the ICE just burns gas trying to warm itself up), or high speed highway drives where the hybrid system isnt used. The touring actually has wider tires than my civic, so that may be hurting the MPG.

    I am not really planning on reducing speed: 119km/h is above the speed limit, but it is also totally accepted. If that means that the prius can't do better than my old civic at that speed then too bad for me. Gas is money, but so is my time.



    I have torque, but for some reason the HV battery gauges dont work.

    I'll check it again later after doing some driving, that is after 3 days sitting in the driveway at minus something temperatures. Could replacing the 12V battery actually pay for itself? Again, I am not after lower MPG for MPG's sake, but rather after economic sense.

    cheers!
     
  11. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Your tire setup seems strange: is that all seasons on the front and snow tires on the bank. Not sure that it would impact mpg seriously, but seems far from optimum/effective. And temps could go up to around 40 psi.

    The 12.2 volt no-load reading of your 12 battery is very low, consider charging or replacement.

    Try setting your cabin temp a lower than 23C, maybe 20C?

    Speed? Yeah, I know, you're not about to start obeying the posted speed limits. What can I say, lol.
     
  12. morglum

    morglum Junior Member

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    Hi Mendel,
    thanks for posting! I know those tires are weird. They came with the car when I bought it this summer. The hankook are called "all weather" tires (whatever that means), but they do have the M+S icon, so they really are winter tires. The bad news is that they are new, so I am stuck with them for a while, so no LRR tires for a while.

    I could charge the battery (we do have a couple charger for tractors on the farm), but shouldnt the battery be more than full after 5 hours of highway driving anyway?

    I'll give a look at the HVAC settings I said 23C by memory and 20C would definitely be reasonnable.

    cheers
     
  13. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Driving will maintain a battery, one that's in good shape, but with a 12.2 volt reading, charging might help. You're obviously just delaying the inevitable, but hey.

    Look for a smart charger, 3~4 amp.

    I use a CTEK 3300, but there a lot of choices.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    Beware that the M+S marking doesn't make it a 'real' winter tire. All Season tires, which are a level below real winter models, carry this M+S symbol. This is sufficient to be an approved winter traction tire in my state.

    The better winter rating is the mountain peak - snowflake symbol. Though your link suggests that your 'all weather' tires should have this symbol too.
     
  15. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    "All Weather" is an expression also used by Nokian, for the WRG2/3, also have snowflake/mountain. They seem to be halfway between an all season and snow, as far as traction, wear.
     
    fuzzy1 likes this.
  16. dolj

    dolj Senior Member

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    I hear this argment quite a lot to justify higher speed, but in reality going 19 km/h faster is only going to increase your overall average speed by a few km/h and therefore not going to get you to your destination quicker by any significant margin. You should do some cost/benefit experiments (100 km/h vs 119 km/h) to prove it to yourself.

    The short answer is no, unless your 12 V battery was in primo condition and you did 5 hours of driving per day, in more or less one stretch. However you said your normal usage pattern was "normally short trips where the car doesn't have the time to warm up completely", so I'd recommend you monitor you 12 V on Torque and charge externally when you notice your resting voltage getting below 12.7 V.

    If you do not have an automatic smart charger (with an AGM setting) that will drop to a maintenance charge once charged, then purchase one. A good charger should not be more than CA$50, but you will pay a little more for a CTEK, which I can also recommend. Any such automatic charger will pay for itself in longer battery life a couple of times over, so is a good investment for your toolkit.

    I also second the advice you have received regarding tires and pressures.

    hope this helps.
     
  17. bisco

    bisco cookie crumbler

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    increased mpg will take a long time to make up for the cost of a battery, but the other problem is that you could get stuck somewhere with a no start if the battery falls much lower.
     
  18. Blizzard_Persona

    Blizzard_Persona Senior Member

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    My commute home is 18.5 miles. About 10-11 miles highway where I use cc and the first few miles are city and few are suburban. If I drive 55mph aka 90kph I get home in 28-30 mins depending on traffic lights.

    When I had my hemi charger and my mazda speed 3's I def drove A LOT faster than I do now. Why you ask, well because hemi, because turbo.. :)

    And as stated in above post guess how much time I shaved off my commute driving like an ahole?

    Maybe 2-3 mins saved if that...

    It is so much more relaxing to set cc at 55-60 and listen to my favorite xm channel. Plus I like seeing my mpg stay at or just over 50 mpg at those speeds in my persona. 75+ mph = mid to low 40's for same commute.

    Now those savings will sure add up over the years by way of cash in your pocket not in the pumps.

    But if those 2-3 mins mean that much to you by all mean have at it.

    Your mpg will def go up to at least mid 40's from the 37 you state if along with airing tires up you stay at or below 100 kph. Try it for a tank full see what happens? If I can do it you can too. :)

    Btw, I'm not a total bore that drives like a granny all the time as I do own a motorcycle that's quicker that most any car on the road.. Now that takes some self control to not wring that throttle. Lol. Although on a closed course in Mexico it might happen from time to time....
     
    #18 Blizzard_Persona, Dec 27, 2014
    Last edited: Dec 28, 2014
  19. morglum

    morglum Junior Member

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    Guys,

    When doing shorter jaunts I do drive like a granny. What I am talking about is a 5h, 500+ km drive that is all highway from Ottawa to an island just East of Quebec city. That 4h30 hours drive would turn into a 5h30 hours drive if I was to drive 20% slower. I have an 18 months old in the back. No way we're adding an hour to the trip to save 9$. I had to do the round trip three times in December due to exceptional circumstances.

    Anyway, I did take the care to the mechanic today. He replaced the tie rod ends and sent me in for an alignment. Numbers didnt look good, now I am back in the allowed interval but I still have big numbers.

    Question: are these numbers acceptable?

    BEFORE
    Front Left
    camber: -1.06 (allowed: -1.33 to 0.17)
    caster: 3.37 (allowed: 2.42 to 3.92)
    toe: -0.22in (allowed: 0.05 to -0.05)
    Front Right
    camber: -0.70 (allowed: -1.33 to 0.17)
    caster: 3.87 (allowed: 2.42 to 3.92)
    toe: -0.14in (allowed: 0.05 to -0.05)

    Rear left
    camber: -1.52 (allowed: -1.00 to -2.00)
    toe in: 0.18in (allowed: 0.01 to 0.14)

    Rear right
    camber: -1.61 (allowed: -1.00 to -2.00)
    toe in: 0.18in (allowed: 0.01 to 0.14)


    AFTER

    Front Left
    camber: -1.10 (allowed: -1.33 to 0.17) . higher than before alignment
    caster: 3.17 (allowed: 2.42 to 3.92)
    toe: 0 (allowed: 0.05 to -0.05)
    Front Right
    camber: -1.33 (allowed: -1.33 to 0.17). higher than before alignment and barely inside the allowed interval
    caster: 3.65 (allowed: 2.42 to 3.92)
    toe: 0 (allowed: 0.05 to -0.05)

    Rear left
    camber: -1.49 (allowed: -1.00 to -2.00)
    toe in: 0.19in (allowed: 0.01 to 0.14)

    Rear right
    camber: -1.64 (allowed: -1.00 to -2.00)
    toe in: 0.17in (allowed: 0.01 to 0.14)
     
  20. morglum

    morglum Junior Member

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    I found the 12V battery receipt. the battery is actually 11 months, bought in February 2014.
    Do you guys still think I need a replacement, or just a charge?
    thanks
     
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