Fuel Economy

[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.

[BMGYaris]

Originally Posted by regulus

so best thing i guess is start counting from the second bar until the 7th vanishes. Ill try that

I never meant to ignore the first bar in your calculations. I just meant that the gas fuel guage is not precise, it is just rough estimates as to how much gas is still left in your tank. Thus no bar or number of bars represents exactly what it does mathematically (mathematically each bar equals 1.387 gallons, but in reality it will not drop at that precise moment). Suppose that on your first bar it was off .21 gallons off. that would be something about 15% more fuel consumed than what you mathematically yield should have been used on your first bar. But the more bars that are gone then the less the margin of error impacts your calculations.

So what this means is that on one bar the margin of error is going to represent some range of fuel consumption, lets say anything from 5-25% more than what you would expect that first bar to actually represent. However, as you use more gas, the actual margin of error (say .21 gallons) should remain pretty consistent (within a range). That means that if .21 gallons creates a 16% inaccuracy when guestimating from your first bar, you will find that the % inaccuracy decreases as your fuel consumption increases. Thus as the total gallons consumed increases the error will represent a smaller portion of your gas consumption. Meaning the more gas consumed the more accurate your bar guage will be, though no one particular bar will be any more accurate than any other. You should always calculate with all available information

Note: im only talking about rough guesstimating before fill ups. Obviously the only way to get true readings is to fill up many times at the same pump. I just didnt want him too be too shocked when his 35 mpg city turned in to 29 or 30...hopefully 32.

[regulus]

Thanks both for the info :D

Ill keep you posted

[swng]

You are welcome and good luck!
BMGYaris' advice makes lot of sense to me. I admire the meticulous calculations.
In my layman's language, all bars do not necessarily represent the same amout of fuel and hence mileage. Depending on how full the tank is filled up, the first bar usually represents anything from more to a lot more fuel than the others. Trying to estimate a car's fuel economy with the data collected from just one bar can lead to a rather unreliable result. The bigger is the database, the better.
Long term averaging and consistency in filling up location(s) and method (I would say) can help minimize the effects of many possible errors.
Good research friends!

[keesue]

Very first tankful = 35.6 miles/gallon

[swng]

The result is quite good keesue, considering that it's your first tank and that winter has arrived (weather should not be severe in San Francisco right now though). I presume you are reporting in miles per US gallon. That will be more than 42.5 miles per Imperial gallon.
Please keep on posting your results from time to time and describe your driving style and the traffic and load conditions leading to your results every now and then if you don't mind.
Thanks!

[keesue]

I sure will. These miles are 85% commuting. I drive at an average of 65 miles/hour. I expect, as the engine breaks in, to get another mile/gallon. I'll keep you posted.

[swng]

Originally Posted by keesue

I sure will. These miles are 85% commuting. I drive at an average of 65 miles/hour. I expect, as the engine breaks in, to get another mile/gallon. I'll keep you posted.

Thank you in anticipation keesue!

[spkrman]

average of 30 mpg over almost 4 gallons, lots of idling (approx 30-40 mins worth)... lots of agressive driving/acceleration, and mostly city miles... pretty awesome given the circumstances!

BP regular gas, btw.

[SimplyYaris]

First tank of gas - 80/20 city/highway 36 mpg. Yes!

[swng]

Latest Tank (not good because of up to 35% of hilly/stop and go city driving):
Fuel Cost
$37.66 (Canadian)

Distance Travelled
533.9 km
331.77 miles

Fuel Amount
39.07 litres
10.32 US gallons
8.59 Imperial gallons
Cost of Fuel
$0.96 per litre
$3.65 per US gallon
$4.38 per Imperial gallon

Fuel Economy
7.32
litres per 100 km
32.14
miles per US gallon
38.61
miles per Imperial gallon

Mileage Costs
7.0538
¢ents per km
11.35
¢ents per mile

[gonzo452001]

my last tank of gas i got 43.1MPG But this tank isn't going to be as good bad weather having to run my deforst a lot wish that had't linked it to the a/c

[palsan]

Originally Posted by gonzo452001

my last tank of gas i got 43.1MPG...

I'm assuming from your profile that you are in French Lick, Indiana, so I'm guessing your numbers are in US gallons. So, how is 43.1MPG (5.46L/100Km) possible? (If it's imperial gallons I apologize in advance)

Have you stripped the interior of the car, removed the seats, removed the spare tire, stripped the paint, ... ?

I mean, Toyota rates the car as follows:
Manual (city/hwy) 6.9/5.5
Automatic (city/hway) 7.0/5.6

Real world results are normally worse than the manufacturer spec sheet, yet you are reporting BETTER results than the 100% hwy numbers. How is that possible?