Tailgate
 

Yeah, I know this is old hat.....BUT.... What are your thoughts on removing the tailgate and the rear bumper and spare tire from a 1997 Nissan Truck? That's got to add up to some serious weight.

Prolly would remove a lot of weight, but might mess up aerodynamics. I think you might be better off working on an aero bed cap, :), you can do both though, :p

Not in the grand scheme, maybe a couple hundred pounds. The amount of force needed to roll you vehicle depends on the weight, and the rolling resistance of the tires. Weight is pretty straight forward, and rolling resistance ranges from ~.006 to .016, so a better bet would probably be LRR (low rolling resistance) tires, since you can likely see way more of a gain there. For instance, if your truck weighs 3500lbs, with the likely Crr of .010-.012, going to a LRR tire may net you a bigger gain. So

weight reduction-3300lbs*.012=39.6lbs
LRR tires- 3500lbs*.008=28lbs

I mean, it'll be an improvement, but it's better to go with LRR tires and have a full sized spare than the other way around.

edit- Ohhh, 4x4 eh? Run dual transfer cases so you can have really low highway OD gears, that could really improve mileage. :thumbup:

The one and olny Scangage test I ran on my F350 diesel showed that lowering the tailgate helped about as much as a plywood bed cover. The difference wasn't much, maybe 0.5 mpg as I recall.

Ooh a hardbody! I put 100k on one of those myself. Mine was 2wd. I tried a few mods in the name of power and economy.

9.5 to 1 pistons
240sx cam
different intakes
taller tires
shorter tires
profiled plugs
tailgate up, down, off
a bed topper

I always seemed to get the same mileage. But I didn't have any instrumentation. And the truck was never properly tuned for the pistons. I generally averaged around 24-26mpg 85% highway. Best ever was 27.1mpg. I generally did full fills.

if you take the tail gate off, what are you going to do with the stuff you are hauling?
I say shift earlier, you have torque to haul over half a ton, in other words you have a monster under your hood, if you have an empty bed, then don't drive like you are hauling a load.