Boys, boys, ,, simmer down..... Everybody drive as fast or as slow as they like. It's just hard for some of us to believe that 'The 600 Mile Club' can be entered without driving slow....
So.. my last tank was 1100.7 KM (683.94 miles), 42.676 L (11.27 US gallons). 26.4 km/l on dash, 25.79 calculated. 800 miles is 1287.5 and that's easily within reach as my last tank suffered a few high speed and very low km/l runs.