Solved

Acceleration or fuel economy

Making changes, I have realized that it is better to have 10 fuel savings over acceleration. How is it possible that 10 fuel savings are so noticeable and 10 acceleration practically nothing?

Every area in this game is described by an inverse exponential function. This means that 10 dp applied where you have 50 points will have an higher impact than another area where you have 190 dp.

Said this, keep in mind that you are in a no refueling league. When you have 180 liters in your tank, an improvement of 10% in fuel economy means 18 liter less which is a huge improvement. You should prefer fuel economy in no refuel while it is worth (it's your role understanding how much and how long).

thanks¡