Would greatly improved aerodynamics make a significant improvement in fuel economy on my '88 Chevy S-10 Extended Cab pickup? I have the 4.3L V-6 and an automatic transmission. I get acceptable gas mileage compared to fullsize pickups, but I'd like to do better. I'd also like to come up with some radical aerodynamic changes just for the sake of doing something different.
I've noticed that many famous race cars have very small frontal areas. Cars like the slant-nose Porsches, Ferraris, Dodge Daytona Chargers, and Plymouth Superbirds, LeMans racers, etc. have almost wedge-shaped noses. Land speed record racers are super-low, thin, and smooth. NHRA Funny Cars are basically a fiberglass wedge that we're supposed to believe is a Mustang or an Impala.
I've thought about various slant-nose cars that maybe I could adapt such as the slanted-grille Vegas, early-'80s Dodge Charger nose sections, various Corvette front ends, or just making something out of metal or fiberglass. I also thought about a radical roof chop with slanted A-pillars and maybe a larger windshield from a car.
I realize that I could buy a tanker load of gas for what it might cost to build a radical S-10, but I'd also like to do it to stand out from all the other S-10s in the world.
On a more practical note, would taping body gaps, door openings, making a mostly solid grille cover, smoothing around the bumpers, and adding a big front spoiler make much of a fuel economy improvement?
It's pretty basic physics that the less wind resistance a vehicle has the less power (or fuel) it takes to move it. Less weight is another basic way of improving efficiency.
As a matter of increasing fuel economy your ideas are false economy, but as a way to build a unique street truck they have merit. An S-10 that's as low and slippery as a Bonneville Salt Flats racer would be neat but not practical unless it had an adjustable suspension to get over speed bumps and potholes. Study photos of actual Bonneville cars and take your styling cues from them.
A chopped top would be great. If vehicle laws aren't an obstacle, how about going for a super, super low lid like those on iconic '34 Ford coupes from the '50s? Those coupes had "mail slot" windows. You could recess the front edge of the roof so a larger windshield could be used for reasonable forward vision while keeping the roof height to a minimum.
Spun-aluminum racing discs (also known as Moon discs) on tall, skinny tires would be part of the Bonneville look and offer less rolling resistance than heavy and wide wheels and tires. You could fabricate rear wheel skirts, but that might confuse the look with a kustom or lowrider. A hard tonneau cover would be a must.
People who want to run a street car on the dry lakebeds have been known to "streamline" them with duct tape. Anything that reduces air resistance improves performance/fuel economy. This includes a low stance, front spoilers, side skirts, tucked in bumpers, shaved emblems/handles, aero mirrors (consider some motorcycle mirrors), and a solid nose (old Superbirds had a small air inlet down low on their extended noses).