another thing to consider is how the engine is used:
for example, there was a road and track that gave mileage for some fun vehicles, such as a porsche gt2, used on a race track.
how quick the tank went, mileage, etc...
the gt2 got 6mpg, and killed its tank in an hour...
so, when driven all out, the same engine got far less mileage...
but that's besides the point...
end of side note...
