How Many Gallons Are In Your Tank?

GJ,

Are you getting the gas mileage quoted with the build at the bottom of your posts? If so, that is damn good. I have some lame ass all seasons and am thinking about getting the Wrangler Silent Armor's. Was wondering how much that will lower the gas mileage.

 

I get 400 to 425 mpg between fill ups, and yes the light is on.

Typically, 18 gals or there about to fill up and I make sure to fill up the stand pipe until it's just about over flowing.

The major difference is when I installed the AFE dry air filter from the stock one that came on the truck at approx. 15k. No, it wasn't dirty I just read some of the reports on TW.

I watch my RPM's and try to stay below 2K.

Hey, I've been driving for 52 yrs so I don't do jack rabbit starts off the light, like I might have done 40 yrs ago...

Hey, my company pays the vehicle payments and the gas, but I still am a conservative, and careful driver because it's ultimately my truck.

When I retire I plan to drive it until the wheels fall off, and I've got the 8 yrs 125 mile extended warranty that's advertise on Toyota Nation. What a savings.

Enjoy the outdoors, hike more and take a friend.

 

This is a 'how many gallons are in your tank' thread, not the 'what is your gas mileage' thread. Please note the gauge needle location or if the light just came on... and tell us how many gallons went in at that point. Okay to tell us how many miles you traveled, but the gallons in the tank at certain points is the point of this post.

 

Okay, filled up today at 'just below' the 1/4 tank line, and overall my mileage was lower than normal this tank (15.6 mpg). Using that mileage for the 3/4 of a tank, and noting my odometer when the needle was over the three marks (3/4, 1/2, 1/4):

At 15.6 MPG:
Full to 3/4 tank was at 75 miles, 4.8 gallons (same as above)
3/4 to 1/2 tank was at 130 miles, 8.3 gallons (down 0.9 gal. from above)
1/2 to 1/4 tank was at 215 miles, 13.8 gallons (down 0.5 gal. from above)
1/4 to E would be at 288.6 miles, 18.5 gallons*
E to Empty would be at 327.6 miles, 21 gallons*
* based on the assumption we have 2.5 gallons when the needle is on the E line.

Please join our survey and record your mileage at the various gauge points, and your gallons at 1/4 tank, light on, or E line fill up. Filling up at 3/4 tank and 1/2 tank lines would be good, too... if you had the time.

 

the total amounts come out well, however you can see the discrepancy of a whole gallon and then half gallon.

i stress the importance of doing this multiple times and then taking note of your best mileage 1/4 tanks as well as your worst. this will give you the most consistent full tank when it comes to mileage in order to get proper gallon capacity for the 1/4 tanks.

If any one or more of your 1/4 tanks did not average exactly 15.6 mpgs then your calculations will be off and this can be as much as a whole gallon or more margin of error. data like this will only get us in the ballpark. to be within .2 or so of the actual gallon capacity you must gather a lot of data and then use your best and worst 1/4 tanks as i explained.

I think we have nailed it that it is a 21 gallon tank and that there is approximately 4 gallons at the E-light and 2.5 gallons at the E-mark. it is the other marks that are in question here. i think if done properly by everyone we can get some similar results.

I filled up yesterday and am starting my "top off" data results. i will still be able to use this data to continue to supporting my previously posted data concerning gallon capacity. I was able to stuff approximately 2 extra gallons passed the normal fill up of the tank.

 

The entire mpg vs. 1/4 tank marks on your gauge is off target.

First of all .... the more you drive (with everything remaining constant) your mpgs will go UP ..... this is because the weight of your vehicle decreases as your vehicle consumes fuel.

When the first oil embargo fo the 1970's occurred airlines did two things. They stopped topping off their tanks and they removed paint from their planes. Both of these decreased weight thus better usage of fuel.

Second - your dash board gas gauge is just that - "a gauge" - not an exact meter.

Many people say, "I get more miles from full to 3/4 because I travel xxx amount of miles before it reaches 3/4. It then goes xxx miles from 3/4 to 1/2, etc".

Just my $52.68 worth .... that is what it would have cost me at WaWa this morning if my tank were empty.

 

Yah, exactly... and for the others who think this is a mileage test... it is a gallons test. We know the mileage would improve with less weight from less gas, and that gas consumption is dynamic. This is about how many gallons are in your tank at various markers. Now, if I happen to be by a station when I am at 1/4 and 1/2 mark, I will be happy to top off and record the gallons... But, either I haven't been or was too busy working to pull over... so, I estimate the gallons at those marks by the milegae I figured when I did fill up. This is on-going, and I will continue to post my results, as I wish others would do, too!

Until we get data (more data) of gallons put in at light and E line... then we shall continue to presume the light means 4 gallons and the E line means 2.5 gallons left in the tank. We are open to data that changes this!

 

For what it's worth... I was at 75 miles at 1/4 tank, missed seeing the needle at 1/2 tank, 225 miles at 3/4 tank... and not near a station so I am pushing on to when the light comes on and hope to be close to a station so I can fill up right then (and see how close to 17 gallons I am then!

 

Just updated the 1st post with about 4 more tanks of data. i now have 12 tanks worth of data and my numbers are about as accurate as all possible.

I don't think it can get better than this. this IS what you have in your tank at the specific markers....

Highest possible- 339 miles to E-light/17 Gallons/19.94 MPGs
5.51
4.11
4.31
3.06
(add these numbers to check our math and you get 17 Gallons which allows us to know we did it right)

Lowest possible- 261 miles to the E-light/17 Gallons/15.35 MPGs
5.27
3.97
4.42
3.22
(Add these numbers and you get 16.9 Gallons which is close enough for me)

Old Average possible- 307.14 miles/17 Gallons/18.15 MPGs
5.37
3.95
4.39
3.04
(Add these numbers and you get 16.8 which is still pretty close and good enough for me-we ARE working with average miles, Average MPGs and average individual 1/4 tank miles)

New Averages since last update: 306.33 Miles/17 Gallons/18.01 MPGs
5.47
4.06
4.38
3.08
(Added up and you get 16.76 still pretty close. again, these are averages so a .25 Margin of error isnt too bad)


Here are the numbers stacked side by side.

High----Old Average----New Average--------- Low------Margin of error
5.51---------5.37 ------------5.47--------------5.27----------.34 (due to difference in fuel ups most likely)
4.11---------3.95 ------------4.06--------------3.97----------.14
4.31---------4.39 ------------4.38--------------4.39----------.08
3.06---------3.04 ------------3.08--------------3.04----------.02

I feel like this is pretty accurate data considering i calculated it 3 different ways and the margins of error are pretty damn good if you ask me. the top 1/4 tank with .3 margin of error and 18mpgs is only a difference of 6 miles.

Soooo in the end you can be sure that your tanks are as follows:

Full to 3/4 ---= 5.4
3/4 to 1/2--- = 4.0
1/2 to 1/4--- = 4.4
1/4 to E-light = 3.0

 

My truck:

Gauge on E...light came on...just a few miles later I gassed it up...it took 18.06 gallons to fill up.

So, I guess I have 3 gallons from the light to empty.

btw...I had 371 miles on the trip-odometer from the last fill-up...I believe that works out to 20.54 miles per gallon.

That's as scientific as I need.

 

Isn't this fun! LOL

Today, my E light came on ... and I got to a gas station in 8 miles (1/2 gallon)... The fill up was 17.3 gallons less the 0.5 gallon for the 8 miles beyond the light activation (I got 16 mpg). Which means this time, for me... the E light came on with 16.8 gallons used or 4.2 gallons to go!

 

Yeah the E-light is the only thing that will vary between us and your right, some just want to know whats left after the light or the E-Mark and don't care about the individual quarter tanks.

I personally like to know exactly what i have left in gallons so as to properly gauge how much more fun i can have out in the wilderness before i have to get back to town

 

Full to 3/4 ---= 5.4
3/4 to 1/2--- = 4.0
1/2 to 1/4--- = 4.4
1/4 to E-light = 3.0

Full to 3/4 -------= 4.8 gallons
3/4 to 1/2------- = 4.6 gallons
1/2 to 1/4------- = 3.9 gallons
1/4 to E-Light----= 3.5 gallons

We are only 1/2 gallon apart (0.6 in the first half and 0.5 in the second half)

 

yeah we are only a little bit off but its really because you havent had enough tanks and the data that you do have is a little inconsistent...

Your data that you have put up so far is this:

F-3/4--------81.6----75
3/4-1/2------78.2----55
1/2-1/4------66.3----85
1/4-E mark---88.4----73

Your 3/4-1/2 tank can not be accurate with a difference of 23 miles or so.
Your 1/2-1/4 has the same problem
Your 1/4-E Mark is not as bad as the above mentioned but has 15 miles of difference.

you cannot get accurate information with data like that. you can get close though, which is why our numbers are not far off.

You need numbers like my last F-3/4 tanks...they were 100-102-103-100.

The reason for this is as follows:

on the 1st tank you averaged 17 MPGs but it is certain that on the 1/2-1/4 mark you did not get this MPG. This is going to throw your information off when you try to divide 66.3 miles by 17 MPGs. you probably should have been dividing by a lower number than 17. Same thing for the high numbers. Some of the 1/4 tanks probably should have been divided by a higher number than 17 since 17 was just an average...if your 1/4 tank miles are erratic, then your average MPG is not a good # to be using to divide with.

this is why you need consistent data. The only catch is that its almost impossible to get consistent data throughout a whole tank so you need to do this over 10 times while trying to get the best mileage possible. I'm talking, 5th gear in a 35mph zone and 4th in a 25mph zone, no hard pressure on the pedal when taking off, no passing vehicles, coasting to a stop when you see red lights up ahead, keeping rpms between 2000 and 1000, shifting at 2000, etc...

Once you have tried all this for 10 or more tanks you can now take the best tank of all your data and add them up, divide by the amount of gallons it takes your tank to fill up from your bottom point (E-light or E-mark) and that is the consistent MPG for your "Ideal" tank. now divide your total miles by that "Ideal" MPG and there is your gallon capacities.


our numbers are close but i think we can get them closer once you have a lot more data so as to get the "ideal" tank numbers.

 

Firstly, no my MPG wont go up, SIGNIFICANTLY that is. Gas weighs about 6 lbs and that is only a difference of about 100 lbs to my E-light. this is not going to hurt my mileage by even a .5 gallon!

Secondly airplanes is not a good comparison because you are talking about a lot of weight when you dont "top off" an airplane. also Airplanes travel vast distances and over a long period of time you would see a difference.
It's like saying i saved a penny every day this month and comparing it to if i save a penny every day in the next 5 years! obviously these numbers are bigger.

Thirdly, the gauge in each respective vehicle is exact for that specific vehicle. Your vehicle does not give you a different reading every time you get to 3/4 of a tank. You will have just as much gas left in your tank when the needle shows 3/4 as it did the last time it showed 3/4. This is not going to change.

Just so you know the word "Gauge" does not always mean estimate. it can also mean:to determine the exact dimensions, capacity, quantity, or force of; measure.
The reason we get different mile readings throughout our whole tank is because of the SHAPE of the tank. Due to the fuel line and shape the top 1/4 tank is always going to hold more than the bottom quarters. That is why it always gets more. it is not a perfect square so parts of the tank hold more and less gallons.

 

The best way to determin what's in 1/4 tank amounts is to fill up at each 1/4 mark. We have been using our mileage per gallon to estimate the gas consumed per 1/4 tank level. It just isn't always convenient to stop and fill up after just 1/4 tank or 1/2 tank.

 

gj, did you notice that our tanks alternate between who has a 1/2 gallon more, per quarter tank?

Your first quarter tank is 0.6 gallon bigger and then the second quarter is 0.6 gallon smaller than mine... the third quarter has you bigger again by 0.5 gallon, then the final amount (to E light) mine is up by 0.5 gallon... ??? Interesting, no?

In the end, we are the same at 16.8 gallons to the E-Light.


Yours vs. mine, so far!
Full to 3/4 ---= 5.4
3/4 to 1/2--- = 4.0
1/2 to 1/4--- = 4.4
1/4 to E-light = 3.0

Full to 3/4 -------= 4.8 gallons
3/4 to 1/2------- = 4.6 gallons
1/2 to 1/4------- = 3.9 gallons
1/4 to E-Light----= 3.5 gallons

We are only 1/2 gallon apart (0.6 in the first half and 0.5 in the second half)

 

yes the total amount is the same, however its the in between amounts that have a discrepancy.

If you look at this you will see what i mean...

The .6 on your 2nd 1/4 belongs on the 1st 1/4. and .5 of your 4th 1/4 belongs on your 3rd 1/4...then we are exactly the same

This is only because you don't have a lot of data and what data you do have is pretty inconsistent. As i have said before, i bet if you started new, took consistent data for the next 10 tanks, then took the data for the best 1/4 tanks, added it up, divided by the gallons it takes you to fill up from that point, took that MPG number, and divided it into the 1/4 tanks that your numbers would come out right on those individual 1/4 tanks.

all the tanks are about a .5 Gallon different from each other. you have one of them being almost a whole gallon different than another. Of course the reason for this is the data used. trust me. if you did 10 tanks and took the best from them you would get proper results.

like you said we are not far off, but its enough to show a decent difference.

 

OK...come clean, you guys are the dudes from the TV show "Big Bang Theory"...right?