Dash calculated fuel consumption average vs hand calculated average

[RikDavis]

My hand calculated mileage since I got the truck is 15.3 . The evic is no where near that most of the time and is always high. Maybe the last batch of computer updates will address that.
Since I run 2 tanks I am usually resetting at 800 miles or more. I could try some shorter runs using just one tank to see if it is more accurate.

 

[photowrite]

I have read with interest on this thread and with all the math and opinions that have been thrown around, it appears that there is one key factor that has only been "assumed" in all the calculations...Tire Size. The EVIC's are calibrated with the OEM stock tire size, if an owner puts a different tire size on the truck then all bets are off on a reasonably accurate calculation. A stock 265/70/17 tire has a height of 31.6" and a rolling circumference of 99.2 inches, while a 285/70/17 has a height of 32.7 inches and a circumference of 102.7 inches. This is about a 3.35 percent change, which at 14MPG is a difference of 0.4mpg. So with all the math and discussion, we have to assume that we all are running stock tires, OR everyone has calculated for the difference in tire size from stock.

Correct, a very valid point. And this is exactly why for an article series I'm working on for later in 2015 I test odometer error for all tires, stock, and aftermarket. For data to be accurate and valid we must try to eliminate inaccuracies and variables.

 

[Sticks]

WOW. I thought it was well established way back when, in the before time, when they first started putting them in the trucks that we called them Lie-O-Meters for a reason. Both the Fuel gauge and the MPG gauge are notoriously inaccurate when it comes to Dodge/Ram products.

Even my gasburner is optimistic (on all three options) as to what my MPG is. No less than 1.7 mpg high. I just know that when the low fuel light comes on, I have +/-50 miles to find it some food.

 

[Trowel2013]

For you guys that brought it up, my truck is completely stock. Stock 17" rims, stock Transforce AT tires stock everything. Almost 16,000 miles.

 

[jacknife]

i fill up the tank and drive . when it gets to half my transfer flow fills it back to three quarters. When the filling light comes on I stop looking at the fuel gauge . When it goes out I look and wala ! back to three quarters and you can't beat that ! LOL.