How are you figuring fuel mileage

[DalDMax]

I keep seeing people posting fuel mileage numbers and am curious as to how everyone is determining their mileage.
I keep a fuel log. Take the figures from the pump, divide my miles since last fill up and use that number. However the problem I have is that when filling up, you never know exactly what level you are filling the tank up to, because of the foam. Sometimes I get a lot of foam, sometimes I get very little foam and I'm sure that this is skewing my numbers back and forth.
Before the Juice, my DIC numbers never jived with my figuring so I didn't and don't trust it.

[Bigwheel]

Well, all I know is when my Low Fuel light comes on I know I have about 5 gallons left, when I came back from a trip last couple weeks ago, I had 430 miles on her and filled up. I read the gas pump and says 23 gallons, I had 3 gallons still left, so I divide 430 with 23 gallons just filled, hence 18.7 miles per gallon. Foam or no foam, the pump still measures fuel comming out of the nozzel, I don't think pump would miss-measure because foam hitting nozzel so it shuts off. Or I may be incorrect. :rolleyes: :eek:

[AbqGeorge]

Like others have found, the DIC readings on my truck are a bit too conservative 10-20%. I use a log book and always fill it as full as I can get it.

[sdaver]

simple math miles divided by gallons.....fill the neck slowly.... :D dave

[Flyboy]

I fill mine 'till it won't hold another drop. Go slow at the end to top off. The automatic shutoff nozzels mix air with the fuel causing a lot of foam. Have to wait until the foam settles. Don't top off gas vehicles, you'll put raw gas in the vapor canister.

[DMAX Daddy]

fill at same pump everytime on slow til it shuts off, use pencil and paper.

I get roughly 14mpg, which isnt bad considering my 99 gas suburban got about 9 or 10 on the same stop and go 6 mile drive to work. Most mornings I warm up for longer than it takes to drive it!

[Tsckey]

I use the same technique as Flyboy. The foam is annoying, but pull the nozzle up a little from full insertion and be patient. As the foam dissipates, squirt a little more fuel in and wait, squirt and wait until you can't get anymore in and you're done. If you're careful you won't spill any and you'll never have to guess at the fill level. I don't have the DIC in my truck and use a little solar calculator and the ancient method of dividing the miles by the gallons. Works pretty well.

TC

[TBC]

I fill to same point, full into the top of the neck of both tanks. Divide miles by gallons. I never trust one tank to give me an accurate MPG average. I track every tank full and keep a running average. I watch each tank full for any radical changes. Especially when towing and on a trip where conditions are changing, ie terrain, weather, roads, I expect variations and sometime big ones. Last trip over 1500 miles was everthing from hills, to mountains and high winds. Low tank was 8.2 and high tank was 13.3 and other figures in between but an overall average of 10.5.

Caution is to be sure you taking a real average for a trip or for everyday driving or whatever other situations you find yourself in. The number vary but don't trust one tank for accuracy. A lot of folks do that and consequently you get some inaccurate data. My lifetime over 34000 miles is 13.9 MPG covers all my driving trips.

Tom

[richp]

I think the best fuel economy figures result from multiple tanks over lots of miles, evening out fill-up variations, ambient temperature fluctuations, fuel quality changes, driving variations, terrain, wind, etc.

I've kept a log of all fuel, mileage, and associated vehicle costs since day one with my K2500. Periodically I crank those numbers into a spreadsheet and look at the results.

Best mileage was 24.39 MPG -- I never believed this particular number, since most other high-mileage tanks are in the 20 MPG range.

Worst mileage 7.63 MPG -- towing a tall trailer fast against a headwind through western Nebraska on a VERY hot day.

Overall mileage for first 59,777 miles -- 13.23 MPG, with about 2/3 of those miles towing a 32' fifth wheeler.

Overall cost of ownership -- $0.73 per mile and dropping about a penny every 1,000 miles.

For what it's worth.

Rich Phillips
member #28

[chuntag95]

My DIC doesn't have mileage, so I have to do it by hand. redface.gif Well, actually Excel :D which I chart 3 different values. One is lifetime, total miles and total gallons for 15.897 miles/gallon (28786/1809.26). The second is last 10 tanks at 16.106 and the final is last tank at 16.976. I do wish I had numbers like MaxRock at over a 20 average lifetime, but I don't drive a hand shaker either.

[Idle_Chatter]

You could try my Excel spreadsheets in the link below (the "big" one is a little bit over the top, but that's the way I do it :D ) Having two tanks, I try and shift at the low fuel light and put in the same amount each time - 23.5 in the main and 32.0 in the aux.