how bad are big vans are aerodynamically

[aerohead]

Originally Posted by racprops

And the Toyota gained 14.76.

I am disregarding your highs as I am not throwing in readings of taking a Toyota and a Hyundai from 32MPG an getting readings of 60 and 70 MPG using Hydrogen systems as we could not do them twice…Yes a unicorn….but it happened on two cars (out of 14) and one drove home complaining to us about ONLY getting 62 MPG on two fillups…after we saw 72 on one drive test.

Rich

The longer you stay in the game, the more you'll realize that your vehicle will demonstrate a natural mpg variability, especially on a coast-to-coast run, with zero change to modifications.
I provided an entire mpg breakdown, tank-by-tank on my road trips for 2014 and 2017, with all route data.

[cRiPpLe_rOoStEr]

I was more familiar with the 4th-generation Toyota HiAce, which was still fairly compact. The newer one is quite large.

[cRiPpLe_rOoStEr]

Not sure if such setup would effectively have less of an aerodynamic penalty than the equivalent US-spec van of the same era...

[aerohead]

Originally Posted by cRiPpLe_rOoStEr

Not sure if such setup would effectively have less of an aerodynamic penalty than the equivalent US-spec van of the same era...

That would have been the 1st-gen GM, Chevy S-10 / GMC S-15, circa 1984- 1991. They were around Cd 0.475, naked, as a pickup, and as low as Cd 0.315, and 211-mph, with the aero modifications made to the Gale Banks Bonneville LSR race truck, circa 1991.
A 'level' bed cap would have helped. The one depicted is adding frontal area, so it would be cutting into the drag reduction. Maybe break even.

[cRiPpLe_rOoStEr]

Originally Posted by aerohead

That would have been the 1st-gen GM, Chevy S-10 / GMC S-15, circa 1984- 1991.

It's a square-body C-series. Brazilian versions had a slightly different design.