Hint
What is the most optimal refuelling in the championship mode in the first level?
Track 1 (2 laps): You can cross the track without refuelling.
Track 2 (1 lap): You can cross the track without refuelling.
Track 3 (1 lap): On the last station get fuel only above red line.
Track 4 (4 laps): In the second lap get maximum fuel and you don't need anymore.