I use an app to track my gas consumption to see what kind of mileage I'm getting. Most of my searches on the Internet have the Mini tank at 40 liters but, while looking through the owners manual, I saw it has the tank at 44 liters.

Which is it?

 

It's 44 L.

 

Caution: Don't do like a few and run the tank dry just to find out. The result is often a burned out fuel pump with accompanying cost of replacement.

 

Yeah probably as bad as topping off a MINI fuel tank, which can lead to a faulty Leak Diagnosis Pump and/or damaged charcoal tank filter....