Anything over 14 doubles the fuel mileage that I get with my Ford V 10, when “NOT” towing anything! memtb
Ha ha.
I bought a C class with that motor in it, drove it from Fresno CA to Eastern WA......................yep, 7 MPG.
All the torque I needed to get it up some hills along the way, and there are a lot. Some big ones too.