Well, I think it is more than 2.8L.
I just poured engine flush in my engine this past Monday (when I had complete, regular maintenance work done for my ride. I will explain all the details later in this thread, IN SHA ALLAH) and let it idle for 10-15 minutes, and then drained engine oil. New Engine oil quantity poured was 3L (i.e. more than 2.8L), and it is just touching the max. mark. So IMO, quantity of oil poured after engine flush can be slightly more.