The Basic Fuel Calculator is now a view of the Fuel Calculator PRO
Since version 6.26 there is one Fuel Calculator, in the PRO plan of Raptor Racing Overlay. The old basic one is still there: it's a view you pick inside it.
The BASIC view shows the same as the old calculator: the FUEL in the tank, how many laps it LASTS (green if there's spare, amber if it's tight and red if you must refuel), each row's USAGE per lap, and at the bottom TO FINISH and SPARE or MUST REFUEL.
As always, it only reads iRacing data: you set your pit stop fuel yourself.
The BASIC view: not enough, refuel 6.38 L.
How to pick it
In the Raptor Racing Overlay menu, open the Fuel Calculator PRO settings: in the THE MATH tab, at the very top, is VIEW, with PRO (the default) or BASIC. You can also change it by right-clicking the calculator, under View.
Everything else is in the Fuel Calculator PRO manual.
