notsoricer

Is it just me or are my calculations showing better gas milage when i fill up from a 1/2 tank vs from empty? usually when i fill up a half tank, my calculation show 16-16.5 mpg vs a full tank showing 15-15.5 mpg. i would think the opposite would be true because of the weight loss through full consumption.

FlameRedJK

I have no idea if it makes a difference or not but I usually never put more than a half tank in at a time...I figure it's less for someone to try and siphon and at a lil over 8lbs/gallon that's like 80-90 less pounds I'm hauling around...not that 80 something pounds makes a difference considering all the heavy shit we put on our jeeps

Ezekiel97

I seem to get good mileage from 4/4 to about 1/2 then below that it seems like my mileage drops bad

DRS-JK

Same here.

notsoricer

thats what I'm saying! so I'm not alone.. but why is that??

nvertflyer

these fuel posts for jeeps really crack me up...but...the computer fuel calculations are only estimations and subject to a whole crap load of variables, but since i make my living as a pilot fuel consumption is actually a pretty hot topic for us...there is a old saying and it goes...it takes fuel to carry fuel,for us this includes a change in cg lift to drag ratios etc etc but the one thing we have in common with these aerodynamic nightmares we call jeeps is a change in weight as fuel is consumed.fuel weighs aprox 6 lbs per gallon,in a jk with a 22 gallon tank thats only a whopping 66 lb difference between a full vs half tank...is this enough of a weight difference for the computer to detect and display to the driver...i doubt it.

dognights

Lol crackheads. Sorry all the MPG posts just are out if control. The reason why it seems like you get worse mileage out of your tank from 1/2 to empty is because of where the fuel float sensor is set to. When you are reading half a tank you are actually at less then half a tank. Plus all of your tank is not used as a measured amount. Your fuel light comes in with almost two gallons left in the bottom.

ronjenx

The OP said he calculates his fuel mileage, so that would eliminate the computer display, and the fuel gauge's lack of linearity.

But then, when he says he calculates the mpg, does he really mean he uses fuel pumped, and distance driven?

notsoricer

Thanks, you must be really smart. But not smart enough to read that I CALCULATE my milage and not rely on any fancy on board computer. When I fill up approximately half (11gal), I get better milage than a full fill up (usually 20 gallons). I use "gas cubby" app and I sometimes do the math on paper. The app is just as accurate plus it saves all your data.
This isn't another "how can I get better mpg?" post but thanks for you concern and constructiveness.
Btw, crack is wack.

ronjenx

How many times have you observed the difference between a 1/2 tank fill-up, and an empty tank fill-up?

How far do you drive right after each fill-up before parking the Jeep?