Fuel Economy

[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

[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.

[wushumasterku]

^ why do you use 91 or 92??

[Ziv]

Originally Posted by wushumasterku

^ why do you use 91 or 92??

why not? when I was driving my old altima('99), 91 and 92 last better than 87.

[p2filz]

Originally Posted by Ziv

why not? when I was driving my old altima('99), 91 and 92 last better than 87.

higher octane only makes the gas burn slower so that higher compression engines dont knock and ping. i dont know about cleaning agents in higher octane being in higher quantity but what ever like said before if the car specifies higher then do so if not dont those are my $.02

[why?]

Originally Posted by p2filz

higher octane only makes the gas burn slower so that higher compression engines dont knock and ping. i dont know about cleaning agents in higher octane being in higher quantity but what ever like said before if the car specifies higher then do so if not dont those are my $.02

Almost all cars will be able to adjust for higher octane gasoline, so their will be some benefit.

[Idahotom]

I just returned from a very quick trip to Las Vegas and back, no hypermiling, on cruise the entire time, a couple of miles above the posted limit, and there were some 80 mph posted stretches! The rest posted 75 with some 65 around the bigger cities. Once there a little city driving. A little over 1100 miles in all....37.7 mpg average. Now back home, and in no hurry, it'll be my usual 40+ mpg.

My favorite route to town is a 45 mph posted highway, that I drive at 48 to 50, on cruise, and get 50+ mpg, my last motorcycle would do that, but it had no heater or other creature comforts!

[Idahotom]

Originally Posted by why?

Almost all cars will be able to adjust for higher octane gasoline, so their will be some benefit.

If one wants to waste their money on premium fuel for an engine it is not needed for, thinking they are getting "extra power", I don't have a problem with that. I'll continue to use regular.

[swng]

There are people who believe that higher octane fuel can give them better mileage. Some say higher octane fuel will also make cars last longer and maintenance cheaper and easier. I do not want to dispute. People are entitled to make their own judgements and free choices. I only want to point out that higher octane fuel can cost up to 10+% more than Octane No.87 fuel, and it is highly doubtful if one can get 10+% more mileage by switching to higher octane fuel. Also, some people feel that higher octane fuel can make their cars more peppy. If that is true(I don't know), I think it will be up to the individual concerned to decide if the perceived improvement can justify the additional cost.

For myself, if the user's manual says Octane No.87 fuel is o.k., I will use it, as long as my car is properly maintained and not too old.

[GabL]

Should follow what the user manual recommanded to you, I think the manufacturer knows more about the car than yourself!

http://autorepair.about.com/od/engin...hoctanegas.htm

[wushumasterku]

for me, i only use 92 or 94 in my prelude cuz it requires it
and in my xterra supercharged, it required it too.

i was waiting for the day my yaris came in so i can start using 87.

[why?]

Actually in the USA they use 93 octane for the testing procedures for gas mileage and for horsepower. It makes it so they do not have to change fuels for different vehicles.

Higher octane fuel will definately give more power if the vehicle's ECU can adjust for it. Same thing for gas mileage. I'd be surprised if you could find a vehicle that would not adjust for slighty higher octane fuel.

Still, the actual cost vs extra mileage would have to be figured out.

[Ziv]

For those of us in North America, I am sure you guys have heard enough commerical about 'higher octane fuel' will make your car goes better, more mileage, better for your engine.... etc. Matter in fact, Petro Canada have a commerical about keep using their WINTER FUEL would 'clean your engine' effect or sort.

Any of you believe any of that? and how relieable is the source of Petro's Commerical compare to >about.com< for 'high-octane gasoline does not outperform regular octane in preventing engine deposits from forming' ??

For meself, I will stick with my experience (91,92) for now, but the manual DID mention about using 87. Plus I went to the dealer yesterday and they said yeah, use 91, use 91! ha ha......... so it's like a crossroad.

[why?]

Gasoline itself does not clean engines. Additives that gas companies put in their gasoline is what does the cleaning.

Gas companies usually put the most and strongest additives in the highest octane fuels.

[yariman]

The Yaris engine is designed to run on the fuel that is recomended in your manual. ( different parts of the world ) Unless you can change the timing and fuel maps etc. it won't run any better on a higher octane fuel. There are more additives in better fuels such as Chevron has more Techron in their higher graded fuels.