Ways to pull fuel economy out of my truck?

Question

i have an 86 gmc sierra 2500 4x4 (reg. cab, 8' bed) the driveline consists of a slightly bored 454, a th400 trans., unsure of transfer case and front diff. but i know the rear is a 14 bolt stuffed with a detroit locker and 4.10's. i plan on adding an aftermarket fuel injection system and a gear vendors overdrive, any other tips without anything drastic like drilling holes in the frame, pulling the mirrors off, and taping over all the gaps? i already know the obvious things like accelerating slowly, keeping the tires inflated, and driving in general with sanity.

thanks in advance for any help

Answer 1

I put a cover over my bed. If you installed a 5 or 6 speed tranny, that would help. My 95 chevy 1/2 ton with a mild 350 will get 22 mpg on the highway at 65 mph. You may want to change your gearing too. Try going with either a 3.73:1 or a 3.42:1 ratio in the diffs.  

Answer 2

Are you trying to get up to like 10 MPG? If you want to get economy, put in a small engine and 3.42 gears. You should be able to get 15. Or just buy a cheap car to run around with

Answer 3

You named the best stuff for economy. And use cheap gas, but with sufficient quality. Unless you don't want to use overdrive, slowing to 55 mph isn't going to make much difference in your mileage:

Use a tachometer to watch the engine speed: At 35 MPH the engine speed is probably the same as 65-70 in overdrive. At 25 mph the engine speed is about the same as driving 55 since the tranny is in a lower gear, but for a longer trip duration. At highway speed there is wind drag, but there is total time of the trip you can finesse. With all these balls in the air, I'd say get there in the shortest time and shortest distance and all the other stuff you've decided on and there can't be much more improvement than that.

These days, I see people get to a down hill and HIT THE DOGGONE BRAKES  because they want to keep it at 55mph. You and I are smarter than that- down hill is a free boost and they waste it all in the brakes. If you have to live with a big engine, take it easy, but sensible. None of the gas saving tips are going to put gas back in the tank and I think some folks believe slowing down does just that.

There are folks who believe that creeping at idle up to a red light saves gas. The engine is going to idle, vehicle moving or not, but if you can avoid stopping altogether you may save a quarter teaspoon of gas you'd need to break arrested inertia. Creeping is a little dangerous, though. Actually, creeping faster than 6 MPH keeps the engine from idling- it runs faster from the torque converter in automatics pulling the engine. Your engine is supposed to idle at about 700rpm, but while creeping 10 mph the engine speed is held at about 1100-1200 rpm. You might as well go to the line and stop with the red light.

I guess the only thing you didn't mention- we didn't mention- is tires with lowest rolling resistance. Maybe that can save a little gas. The petroleum needed to make the tires is gone, never to return and the money to spend on a new set of tires will help the economy.

Enjoy that 300 horsepower while you can. Keep the slowpokes behind you, out of your way.

Answer 4

I'd recommend a sledgehammer and 15,000 dollars.

Answer 5

i would set the truck aside and use it sparingly if you don't want to give it up, and invest in something smaller

The savings would more than make up for the use of the more efficient car and you'd still have your truck when you need it

however, if you use your truck for work, then i would consider documenting everything so that you can get a small tax break