I modded the fuel usage app that you can get over here:
V1.19 Demo Video
The primary reason for the mod was to support fuel loads greater than 99 liters, but then I added some INI options to add new features, like comparing last laps fuel usage to the average, setting the background opacity, etc. The V1.19 is an attempt to adjust the app even more to be relevant for endurance racing. It can now calculate fuel to add on your next pit-stop as well as show your last laps fuel consumption compared to the average fuel consumption.
Also, the app should never suggest more fuel than you would need to complete the race (plus the specified overage).
From the INI:
;Set Values to 1 to turn them on, 0 to turn them off, unless otherwise specified.
;background toggles showing background.
;backgroundOpacity is a float, but only 1 digit of precision (0.1, 0.2, etc). 0.0 to 1.0 are valid.
;HideIcon hides AC icon.
;backgroundBorder toggles the app border being on or off.
;showBlinking toggles blinking at the start of a lap.
;acceptableOverage is the amount of extra liters used on the last lap deemed "acceptable" (blinks yellow). Default value is 0.05, but anything like 0.01, 0.1, or 0.2 should be fine.
;gui_scaling scales the size of the whole app by whatever floating point number you specify. 1.0 is the default.
;lapsOverage is the amount of extra laps to automatically add to the caculation of how much fuel to add. 1.0 is the default. Any float greater than 0.0 is acceptable.
;lastLapsFuelDelay is the amount of time in milliseconds to "blink" the last laps fuel consumption and laps remaining at that fuel rate. 5000 is the default.
background = 1
backgroundopacity = 0.0
hideicon = 1
backgroundborder = 0
showblinking = 1
acceptableoverage = 0.05
gui_scaling = 1.00
lapstocalculate = 17
lapsoverage = 1.00
lastlapsfueldelay = 5000
V1.17 forces two decimal places on some of the labels and writes to the screen every tenth of a second.
V1.18 removes the app title and adds a gui_scaling option to the INI
V1.19 added ability to calculate liters to add at the next pitstop. streamlined some feature and removed others to reduce complexity.
If you have any questions or ideas for improvements please let me know.