No time difference from full to empty tank

I don't remember my lap times. I always drive the entire session, everything at 100%. In the race I immediately drive qualifying times with a full tank, provided I start with the red set of tires. With yellow tires I drive 1-2 seconds slower. But there is no weight simulation in my game. And if I can compete for victory with a controller, with a strength of 105, at the beginning of my career, with the worst team, as a casual player, because of this bug, something must be wrong.