[Big Dave]

This might get moved but I think it speaks to the direction we should be moving.

I have two four-wheel vehicles: A 2000 F-350 with a 7.3L diesel and a ZF6-650 transmission; and a 1996 Chevy Impala SS with a 5.7L (LT-1) engine and an automatic transmission (4L60E). Both vehicles are 4x2 and have 3.08: gears.

The Impala weighs a little more than half what the F-350 weighs. (Curb weight forboth).

The Impala has a smaller frontal area and probably a lower coefficient of aero drag.

Both vehicles' tires are aired-up rock hard and both have fresh front end alignments.

I drive the F-350 with very moderate hypermiling (a bit of engine-on coasting and timing of lights) and it pretty much gets 26.5 to 27 MPG routinely.

I hypermile my brains out (coasting, timing lights, drafting, brakes-free operation (it corners much faster)) in the Impala and struggle to get 21 MPG on occasion.

The F-350 gets better MPG in the winter than the Impala gets in the summer.

Does this not speak volumes for the superiority of the combination of diesel engines and manual transmissions or what?