[ThrustVectoring]

There's a tradeoff to be made with amount of fuel loaded into the car. If you put more fuel in the car, it weighs more, and so will corner and accelerate worse and have worse lap times. On the other hand, it'll have more fuel, so it won't need to make a pit stop as soon.

Qualifying laps are structured differently from the actual race itself, in a way that incentivizes putting less fuel in the car. Essentially, only the qualifying lap times matter, and not the advantages from having more fuel loaded. The obvious strategy is to put the bare minimum in the tank for qualifying, and more during the start of the actual race.

The new regulations forbid that strategy - you're allowed no more fuel to start the race than you had used to start the qualifying laps.