Fuel Economy

[swng]

Yes friends, winter hurts our fuel economy in a number of ways, several of which have already been pointed out by some of you above. It is "comforting" (forgive the not too appropriate choice of word), however, to understand that many other cars are probably more hurt than our Yari.
Anyway, to help form an impression about how big the damage is, please keep on updating your numbers here throughout this winter.
Within safety limits, let us try our best to achieve good results despite everything.

[Pars]

Seem like the cold weather and winter gas is going to take about a 4mpg hit on the Yaris. Probably more if you have more then a few cold starts per day and are driving short distances.

[swng]

Yes! Also, IMHO, tires become stiffer in the cold, producing more rolling resistance. Snow tires may be better but only to a certain degree, and most of them inherently have greater rolling resistance than summer tires. The engine takes longer to reach the ideal working temperature, and in many a case, it has to work against oil that has been thickened by the cold, at least initially before the car warms up fully (synthetic oil may have an advantage in this respect).
Besides, people tend to eat more, wear more, and carry more stuff in winter (it is prudent to have a blanket to keep warm, some first aid stuff, a few coins for emergency phone calls, a chocolate bar and other things, e.g. a battery operated torch, in the car just in case we get stranded anywhere in the cold weather far away from home). All these make the load heavier. I have been told but forgotten the source that a mere addition of 5 lbs can produce a noticeable difference in the fuel economy numbers in the long run.
Limited visibility and poorer road conditions may also prevent us from driving at the optimum speed(s) for fuel economy. Reduced traction can render the using of some fuel saving driving skills inappropriate. For example, in summer, we can let the car cruise down a slope at the highest possible speed as far as it is safe and then use the momentum to make the car move on for a while after the slope ends. In winter, the roads are more slippery and our downhill speeds must be reduced for safety and hence less momentum can be gathered for later use.
These are but a few factors which affect our mpg numbers adversely in winter. I can think of more and I am sure many of us know a lot more such factors, technical or otherwise..

[BMGYaris]

well my first take was 29 mpg, but i drove really really fast on the interstate so no surprise. Then i took it in to get the alignment fixed the same time i filled up. My second tank has just yieleded 23 mpg all interstate never over 80, mostly abotu 70, tire pressure is checked oils and all checked, nothing really to explain it so its going in to the shop monday and they will run some test and all...lets hope they can fix him or they give me an awesome trade up:)

[Yaris]

Originally Posted by swng

I have been told but forgotten the source that a mere addition of 5 lbs can produce a noticeable difference in the fuel economy numbers in the long run.

I've noticed my mileage fluctuating depending on whether my wife gains or loses weight.

[swng]

Originally Posted by BMGYaris

well my first take was 29 mpg, but i drove really really fast on the interstate so no surprise. Then i took it in to get the alignment fixed the same time i filled up. My second tank has just yieleded 23 mpg all interstate never over 80, mostly abotu 70, tire pressure is checked oils and all checked, nothing really to explain it so its going in to the shop monday and they will run some test and all...lets hope they can fix him or they give me an awesome trade up:)

Good luck and please keep us posted!

[swng]

Originally Posted by Yaris

I've noticed my mileage fluctuating depending on whether my wife gains or loses weight.

Lovely! How humorous and how observant!
Actually more advices say a 100 lb difference in load can mean a 1 - 2% difference in the fuel consumption rate.
Please see:http://www.google.ca/search?q=fuel+s...ient=firefox-a

Incidentally, the advice below is from:http://www.tdc.ca/savinggas.htm

"Personally lose some weight. Yes, if you are overweight and need to lose A FEW POUNDS - do it and you will save gas because the weight in the car you are driving will be reduced. We know that there are a high percentage of people who live in North America who are definitely overweight... what a great incentive to lose A FEW POUNDS when you rationalize it by saying you can save a few dollars on fuel as you lose some of your personal weight"

I have capitalized a few words. Please go to the middle of the linked page to see the paragraph in its original form.

Good health to your wife and you!

[eTiMaGo]

It's quite true, on a lightweight car the weight of the occupants can be a large percentage of the total weight, and reducing this total weight should include a good diet

[BMGYaris]

PLEASE READ:

I posted a few post up. I havent gained any weight and my fuel is of the same quality (dont think we get much winter mixture down here in south carolina) but i have an update on my problems.

Just last night i was driving, engine still cool, no problems though. i turn at a redlight, get giong about 25, tap the gas and suddenly there is a loud high pitched..whirrrrrrrr and

i was hardly accelerating at all. i let go of the gass...i turn of my music, tap it, whirrrrrrrrrrr,

i quickly feel the automatic clutch, its in drive, i pop on the light to confirm, not in neutral, not in third, in drive, i check the parking break, its fine, i tap the gas, whirrrrr

i start to pull over and tap it one more time and its smooth as butter, regular deep voice of automatic transmissions shifting gears. no problems the rest of the night.

I suppose what ever has caused my drastic decrease in mpg all the way down to 25 all highway driving at average 65mph is also causing this problem. Anybody have any ideas what is wrong before i head of to the shop on monday let me know.

[ECHOKnight2000]

Originally Posted by BMGYaris

PLEASE READ:

I posted a few post up. I havent gained any weight and my fuel is of the same quality (dont think we get much winter mixture down here in south carolina) but i have an update on my problems.

Just last night i was driving, engine still cool, no problems though. i turn at a redlight, get giong about 25, tap the gas and suddenly there is a loud high pitched..whirrrrrrrr and

i was hardly accelerating at all. i let go of the gass...i turn of my music, tap it, whirrrrrrrrrrr,

i quickly feel the automatic clutch, its in drive, i pop on the light to confirm, not in neutral, not in third, in drive, i check the parking break, its fine, i tap the gas, whirrrrr

i start to pull over and tap it one more time and its smooth as butter, regular deep voice of automatic transmissions shifting gears. no problems the rest of the night.

I suppose what ever has caused my drastic decrease in mpg all the way down to 25 all highway driving at average 65mph is also causing this problem. Anybody have any ideas what is wrong before i head of to the shop on monday let me know.

I really couldn't tell you, the "whirrr" I assume is from the engine not the tranny? Since you said the car is still cool, it doesn't shift into the overdrive gear (4th) but once the engine warms up or gets to "normal" opperating temps it shift, that's if you have an automactic but otherwise I don't know, I'm just guessing. Hope its nothing too serious.

[sanchez]

my yaris with the way i drive( undernormal conditions) can get me at least 370 miles on a full tank

[swng]

370 miles = 590+ km. Not bad !

[palsan]

The owner's manual suggests filling up when the tank is down to about one quarter. When I got the car a month ago and I read that I thought - visits to the gas station more than once a week, that sucks

HOWEVER ... I do about 450kms a week and three quarters of a tank are plenty for that!

Filled up yesterday for the first time since installing winter tires: 497.3Km, 34.78L or 6.99L/100

I can keep filling up on Tuesday or Thursday nights (the cheapest times to buy gas in Toronto) every week and still keep more than a quarter tank

[regulus]

Woot! First estimate.

48 miles for 1 bar of gasoline

comes to about 35 miles/gal

mostly city driving-hurray!!!!

[BMGYaris]

Originally Posted by regulus

Woot! First estimate.
48 miles for 1 bar of gasoline
comes to about 35 miles/gal
mostly city driving-hurray!!!!

dont get too excited , as some other have commented, the top seems take longer to run down, maybe due to the shape of the gas tanke, maybe something else i dont know, but that 35 is probably looking around 30-32...could be less. Dont pretend you have any idea until your down to the last 2 man:) even then its very iffy till you fill up. i hope it goes well though

I mean think about it, if your tank is 11.1 gallons, and you have 8 bars, then each one theoretically is 1.39 gallons per bar. Which is what you used and got with 48/1.39=34.5mpg However, if the bar didnt drop until 1.5 then it is 32, and if it didnt change until 1.6 then it is 30mpg. so for ever .21 gallons the reader is off on the first bar then you are geting - 4.5 mpg. What kind of margine of error you think it has? id say def larger than 0.21 on the first bar

[swng]

Here is a free tool to help estimate annual fuel costs:

http://en.autos.sympatico.msn.ca/fin...estimator.aspx

Enjoy!

[regulus]

Originally Posted by BMGYaris

dont get too excited , as some other have commented, the top seems take longer to run down, maybe due to the shape of the gas tanke, maybe something else i dont know, but that 35 is probably looking around 30-32...could be less. Dont pretend you have any idea until your down to the last 2 man:) even then its very iffy till you fill up. i hope it goes well though

I mean think about it, if your tank is 11.1 gallons, and you have 8 bars, then each one theoretically is 1.39 gallons per bar. Which is what you used and got with 48/1.39=34.5mpg However, if the bar didnt drop until 1.5 then it is 32, and if it didnt change until 1.6 then it is 30mpg. so for ever .21 gallons the reader is off on the first bar then you are geting - 4.5 mpg. What kind of margine of error you think it has? id say def larger than 0.21 on the first bar

True, if what youre saying is true it will make me a sad panda. Will have to wait for the whole tank and see. Thanks for the info :D

About the margin of error im not sure, however I made sure not to take into account the first bar. I think my estimate came from the 3rd bar.

The thing is that if you fill up the whole tank you cant control the amount for the first bar, so best thing i guess is start counting from the second bar until the 7th vanishes. Ill try that

[swng]

Originally Posted by regulus

True, if what youre saying is true it will make me a sad panda. Will have to wait for the whole tank and see. Thanks for the info :D

About the margin of error im not sure, however I made sure not to take into account the first bar. I think my estimate came from the 3rd bar.

The thing is that if you fill up the whole tank you cant control the amount for the first bar, so best thing i guess is start counting from the second bar until the 7th vanishes. Ill try that

May be you do not have to ignore the first bar if you use the calculation methods described in this web page:

https://www.fueleconomy.gov/mpg/MPG.do?action=calcMPG

Please note, however, that variations may exist between different fill-ups. Take a long term average to minimize errors and deviations caused by various factors.