My Truck
 

This is the truck that is currently getting me about 18mpg. It's got a very loose auto-tranny with a lockup torque converter that doesn't kick in until about 50mph.

http://i7.photobucket.com/albums/y26.../Retard001.jpg

There is a headache rack that sticks above the roof by about 4in, and has a metal screen that is difficult to see in the picture. What difference do you think lowering this below the roof line will make for highway fuel economy at 60mph? I've also considered a grill block to get temps up faster and improve aero.

All of this might be for nothing though, as I may sell it and buy my grandpa's '03 Chevy S10.

http://i7.photobucket.com/albums/y26...kes/truck2.jpg

Don't expect any better from the S-10.

unless that s10 happens to have a 5speed manual its the rong kind of s10 to get better mileage in. being that model s10 itll be tougher to get better mileage being the offroad style

What year is your truck? What engine does it have?

I have found that using OD OFF will save a bit of gas on my truck, if I am driving in town and know that I am not going to get up to above 45 MPH.

^^HA! I love the aero cat GIF.

Chop and lower the bar, use it as a pivot for an openable BZP-style aero shell. That's got to guarantee you at least 2MPG. In fact, just read BZP's thread and copy all his mods :D

Also, if you can lower it and use street tires...

No doubt the S10 will likely get worse mpg, but it has low miles on it and grandpa wants to buy a new Tacoma and sell this to me cheep. I can't justify 2 trucks, a Jeep, a car and a motorcycle. Jeep and one of the trucks has got to go.

Year 1998.5
5.9L Cummins turbo diesel (electric fuel pump)
3.55 rear axle ratio

I'll have to try the OD off trick. Perhaps I can find a way to wire up a TC lock switch.

The tranny is tired though, and I just can't see putting $2-3k into it. Speedo stopped working, and I think that causes the grid heater to stay on longer than it needs to.

I like this idea, except I went the other direction on tires. 285/75-R16. I made that tire decision back when I was paying $1/gal for reclaimed fuel.

Here are the tires I'm using currently.
http://i7.photobucket.com/albums/y26...-57-31_501.jpg

I doubt changing the rack will do much of anything measurable. As far as the grille block goes, here's how I did it:
http://ecomodder.com/forum/showthrea...wer-19810.html

Just do a little re-shaping on that brush, throw a tarp over it and you've got an aero cap :D

What MPG improvement did you see from the grill block?

As you can imagine, the load acted as the opposite of an aerocap. The wind resistance was tremendous, and I drove about 50mph for my 70 mile trip. It was early morning and the State Patrol would observe me a while before deciding not to pull me over. Still, I averaged 18mpg overall for that tank.

http://i7.photobucket.com/albums/y26...-57-50_733.jpg

I never really quantified the mpg improvement from the grille block. I did it in several stages, and the weather was changing all the time. My best guess would be around 5% improvement.