Hey guys!

I have had a 6.5L previously (1992) and have sold my DMax in favor of returning to simpler (read as cheaper) times. I don't like the idea of getting hung with $450/piece injector after 100K miles.-:t

Anyway, please vote for what you have installed that netted you better fuel mileage. I have a bone stock 98 (see sig) now and have ordered a 4" exhaust, 3" downpipe, and the larger (2.25"?) crossover pipe that is to be installed next week. I am trying to find out what others have installed to net better fuel mileage (as that is the direction I am heading with my mods). Longevity is a concern, but the truck has many highway miles and I am not afraid of an eventual rebuild anyway. Any and all comments about your mods (whether + or -) are more than welcomed. Comments regarding your experiences with specific vendors are also welcomed (can be PM'd if not comfortable broadcasting)...

:grd:

Thanks!

also consider changing the axle gears to a higher (lower numerically) ratio.

also consider changing the axle gears to a higher (lower numerically) ratio.

You have a good start with the parts you have ordered. I would also go with a chip, turbomaster, an intercooler, and change all your oils in engine and driveline to synthetics. As long as you keep your driving habits mild mannered, these mods will show an increase in mileage by making the engine more efficient. Also, don't forget to do the intake mods like making sure there is no snorkle in the fenderwell behind the airbox, radiusing the inlet tube of the upper intake, a GOOD airfilter, and make sure you do not expose the air intake to underhood (hot) air. The stock airbox is better than some of the aftermarket open air elements on the market.

Oh, and one more thing will make a huge difference in mileage. If you plan on keeping the truck for a while, it might be worth your while to get an aftermarket overdrive unit like the ones made by Gear Vendors. If you make the engine as efficient as you can and then run it in the peak of the torque curve(around 1800rpm I think) , you will acheive best mpg.

i think getting a new airfilter, fuel filter, and gutting the exhaust gave me the most improvement!! The chip was a very close second. As some of you know I was trying to do an optical pump the other day and somehow screwed it all up! Now it is runing fine but isn't getting as much fuel as before, I ran out of daylight before we could play anymore and didn't feel like messing with it at night! Well since it isn't getting as much fuel now I have gotten my best milage of the summer! lol I am almost tempted to leave it like this but I like the black smoke! :-)

also consider changing the axle gears to a higher (lower numerically) ratio.

I did that at about 37,000 miles and I figured it took about 60,000 miles to pay for it but those calculation were at $1.30 gallon Diesel. Two best MPG changes were exhaust and gearing. With 192,000 miles I'm way ahead of the game. If you don't tow heavy consider it. I tow up to 8,000 lbs with no problem. If your towing at or under 5,000 lbs. I would consider about a 3.25 ratio and if you don't tow or only tow about 3,500 lbs I would consider 3.08 ratio.

Goldsburg is that a a short box with six bolt wheels or the HD with the 8 bolt wheels?

I did that at about 37,000 miles and I figured it took about 60,000 miles to pay for it but those calculation were at $1.30 gallon Diesel. Two best MPG changes were exhaust and gearing. With 192,000 miles I'm way ahead of the game. If you don't tow heavy consider it. I tow up to 8,000 lbs with no problem. If your towing at or under 5,000 lbs. I would consider about a 3.25 ratio and if you don't tow or only tow about 3,500 lbs I would consider 3.08 ratio.

You can also the same effect, just in smaller amounts, by adjusting tire size, going larger, at your next tire change.

You can also the same effect, just in smaller amounts, by adjusting tire size, going larger, at your next tire change.

Maybe.......some guys have gone larger (wider & taller) and have had a decrease in MPG because the larger tires have more rolling resistance and areodynaic drag and on the body with raised height. So tall skinny tires are best if your going to that route.

Yeapper I didn't say "wider " Just taller tires. Also some tires are stiffer and have less resistance and better MPG.

This is good info!

Let's keep it coming...

TTT

Yeah, I put my 35x12.5 tires on and noticed a decrease MPG. Then I did my exhaust and it came right back up. I here a new chip will increase the MPG as well. Right now I'm due for some new injectors (~106k miles), so hopefully I will see a little improvement with these as well. But with the possibility of solid front axle conversion and regearing to 4.10's, it's going to throw it all out the window. :muahaha:

I dont know about anyone else but I did the DSG timing gear set and got a better running truck and a good MPG improvement. The timing chain was still in spec when I replaced it.

I've done the 4" exhaust, 3" down pipe and Air intake, got maybe a 1/2 MPG more on the highway. No change really in town. Not complaining since the truck was new and getting about 18MPG in town and 19MPG (19.5MPG now)on the highway. I need to get some new injectors aswell so when that's done I might see better numbers then.