What is the best rpm to run at on the highway to get the best gpm? I have an 01 X with 7.3 psd.

 

2,000 rpm.

 

1800-2000 around 60-70 MPH will get you the best miliage like Rick said.

 

The only problem I have is, at 2,000 rpm, I am doing 62 mph.

 

Gallons per minute???
That's a LOT of smoke.

 

i used to think that, but found that is not the case in my truck.

i would run 2k, ~68mph, and average 18mpg. since i have dropped down to 55, ~1700rpm, i am averaging 20-21mpg.

not all trucks are the same, so you may need to do some experimenting with yours to find its sweet spot.


otoh, i have found mashing the pedal from a dead stop does best for gpm.

 

Dan, that was my first thought, but did not comment on it. Thank you sir. I find my best mpg at 1850, which is 63 mph for my setup.

 

I can't go 62 mph on the interstate. I would get run over in no time here in SW Louisiana. Kind of like in Houston, speed limit 70 mph, you better be going 90 mph to keep up with traffic. I get what I get, and thats what I get.

 

My sweet spot is 1800rpm to give me 22mpg!!! Whoo Hoo!!! It's only about 60mph for me, so I get there slow, but I get there cheaper than most!!

 

I've yet to calculate my empty mpg with economy driving habits, but I drove home on 1/2 tank going about 600 miles. Keep in mind my tank holds 55 gallons

 

I get between 20-21 at 1850-1900 which is about 67-68 MPH. in 80E, 3.73 gears. 285x75 Michelin LTX 60 PSI front - 55 PSI rear. I know, TMI, but all these factors have an effect on MPG.

 

Are you kidding me? 20mpg? That's awesome! I don't think I'm anywhere near that unfortunately. I'm geared and tired up just like you, but no tuner or fuel system/oil mods like you have.

 

No I'm not kidding you. My latest MPG check was slightly laden, some camping gear and 10 cases of beer, about 300 lbs, and from my house to La Sal, UT a round trip of 820 miles I averageg 20.2. That was at elevations at between 5000 ft to just under 8000 ft. When the truck was stock I got 19 mpg. Don't forget to figure in odometer error for the larger than stock tires. My odometer only registers 97 miles for each 100 driven. I add that 3% to total miles for a more accurate MPG figure. That can make a difference. 19.5 MPG uncorrected will be 20.09 corrected.

 

I can get 23-24 sticking to 1850 rpm, the few little mods I have are good for 3 to 4 mpg, so it does not take long at these prices for the mods to pay for themselves.

 

1400 -1600 RPM's probably net the greatest MPG's, but you'll be going pretty damn slow...