Is a 2007 E150's engine considered an ancient engine already? Does this engine do 3km/l? Impossible to get 6km/l from this engine?

What about the 2012 E150s? Do they also do 3lm/l? Impossible to get 6km/l from this engine?

Yes, I need this type of vehicle as I have a big family. Although a Grandia will do the trick as well but the E150 will be more comfortable.