Interesting Fuel Milage report.

[brobeson]

I recently had the opportunity to make the same run from Troutdale to Pendelton Oregon and back several times allowing for a very accurate MPG test. The truck was empty.



Filling up at the same flying J fuel stop after each run of 195 miles each way (390 Miles round trip) I was able to get very accurate results.



Run #1) 55 MPH, no wind, 390 miles, 19. 4 gal. of fuel = 20 MPG.



Run #2) 60 MPH, no wind, 390 miles, 21. 6 gal. of fuel = 18 MPG.



Run #3) 65 MPH, no wind, 390 miles, 26 gals, for only 15 MPG.



Run #4) 70 MPH, no wind, 390 miles, 30 gals, 13 MPG.



Conclusion, my truck likes 55-60 (2000 RPM) for good fuel mileage, but anything more than 65 my mileage drops fast.



Also, this can help explain the vast differences we hear about fuel mileage reports.



While my truck is a dually, 4x4, HO, with 4. 10s, I bet this puts my truck on the low end of the scale, but it would be my guess that this ratio happens to all of our trucks, just the speeds may very.



If a 5 speed, 4x2, 3. 55 did the same test, it would be my guess that the it would get 2-4 MPG more at the same speeds.



Bob

 

[Batman]

Interesting, very interesting. Guess I know why my mileage is fairly low

 

[KatDiesel]

Normally I hover around 14. 5 to 15mpg due to my in town driving habits. A recent trip to KC and back yielded some interesting figures. Including 8 dyno runs and about 2 days of included city driving, I should be right around 18mpg. This is driving 70mph... . I'll fill up later and verify. Going to make another run to KC tonight to race..... so we'll see how that tank goes.

 

[mikel]

On my truck I get right at 19mpg combined highway at 72-75 and Houston around town. I get 2000rpm at 70mph with my 3. 55's. The truck's only got about 3500 miles on it, so we'll see if this improves



Mike

 

[Todd T]

you guys probably dont care about this but here goes,



I have kept track of every drop of fuel I have every put through my truck. here are some interesting facts I have gathered.



total gallons ran through=2113. 53



total cost=$3040. 75



average cost per gallon=$1. 438



over all average MPG (city,highway,emtpy, loaded, etc. )=19. 003MPG



best per tank MPG=21. 16



worst per tank MPG=13. 63



the only other thing, I would like to keep track of, is my average speed. but I would need a GPS to do that.

 

[Archive]

Worst 13.6???

Todd. . 13. 6 is your worst. . I wish I could say that. . Tractor pull this weekend had a good wind and some hills, after about 150 miles the computer said I was only getting 8mpg. . finished the tank with an average of 8. 5 on puter and calculated. . Did better on the way hole with the wind. . but not as windy on the trip bad. . I have gotten in the high 8's many times pulling one tractor. . or two. . (the added weight doesn't seem to make it go much lower. ) This was on the 2001. 5

Bryan

 

[Big White Beast]

I average 12 MPG

Utility bed kills the MPG. Like having a big sail slowing me down. 10K Lbs doesn't help either. Or driving an average of 70-75.



My all time best was 13. 1 That was my first tank after installing the EZ. 10. 5 before that.



I averaged 12. 5 untill I put the DD2's in. Lost a ½ on that.



I have had 4:10's, 3:54's and now 3:73's on the truck and neither made a bit of difference on the mileage. Every tank is a mix of freeway & town driving so what I gained on one end I lost on the other as far as mileage. The 3:73 combo is the sweetest of them all though. Hopefully the transmission mods will help my around town mileage a bit. Right now it seems to just spin and eventually decides to move.



Garrett

 

[Big_Daddy_T]

I get thirteen. If its in 4x4 13. If im on the highway 13. If im in the city 13. If im towing 13. I have a very heavy right foot. Kid in the candystore syndrom I reckon. Although like i said Ive never seen any worse or better with these mods. Before the mods I drove 520 miles on my smallish gas tank with no fill ups. I did the math and pulling two snowmachines I got about 26 mpg. The reason being the roads were crap and I rarely broke 50 mph. Some of this trip, maybe 15 percent was even in 4x.

 

[Cobra]

I don't drive mine enough to be accurate. I generally use it to haul my slide-in. Then I get about 12. 2, however empty it does alot better but as I said I never ran far enough to run a whole tank out. I see 18 to 19 on the computor tho.



Has anyone ever heard of mileges using one of those splitters? I thought about looking into that but with my camper I'm so heavy that I doubt it would be beneficial.

 

[mvaughn]

Mileage

I've got about 4500 miles on my truck and tow a 31' 5th wheel. My mileage empty has been 17-18mpg when running 55-60mph and some city driving added in. Towing is done at 60mph (About 2000rpm)and I get 11mpg. The HO engine seems to like that 2000rpm area.





01 QC 3500 HO Dually 6speed Patriot Blue,PacBrake,K&N Filter

 

[tcoombs]

Batman....

You use fuel, but don't rack any milage while spinning the tires!

 

[DSmith1]

I have done like Todd T and kept up with every drop of fuel that has gone into my truck. My results are almost identical as his with my best being 21. 3 worse 14. 1 and average of 18. 7. This is after little over 8000 miles. My truck has yielded the best mileage at 65 mph on the highway flat 21. 3. If I go 70 which puts me at 2000 rpms it drops to 18. 7 I have done about 2000 miles of towing my boat weighing 5k which once yielded 14. 1 through the foot hills of N. C. when truck was brand new. Based on my experience my trucks sweet spot is between 1800 -1900 rpms. I have not tried 60 mph down the highway since it is all that I can do to stand driving 65 in a 70 mph zone plus it is not safe. I now have a PS boost module and power puck which may be trending to a slight improvement in 50/50 city/highway driving. After I install my DD2's we will see what happens to my mileage (claimed 2-3 mpg improvement).





Dean

 

[Bad340fish]

When i ran to Dallas a few weeks ago I was shocked at how high my MPG was. I went down at night. . going 80 most of the time of course slowing down in the small towns(one which I got a ticket in lol) and did a few runs over 100mph to avoid getting locked in with SLOW traffic. The last 3 hours of the trip were cruise at 80mph mostly. The next night on the way back I got lost in dallas lol, wandered around lead footing my way around town and filled up in Dallas. I was shocked to see I got 19. 4mpg!! My trip computer said 21. 9 2. 5 high as usual due to the EZ. I got 17. 5 on a similiar up there and back trip to St lous. . but I held it at the fuel cut in high gear for over a mile once lol. Truck just rolled 34K.



Also, I have a boost leak, I can only get 24psi with the wastegate disabled, and only can get 16 out of the stock elbow. Oddly enough this seems to have hurt power but helped MPG.



I never had cared about MPG before really... if you see my sig you will see what I used to drive everyday. Double digit MPG makes me smile

 

[NVR FNSH]

I've seen similar results to brobeson in my '00 2500 4wd 6spd w/4. 11s I run 315/75R16s which make my effective gear ratio something around 3. 9



Brian

 

[carhauler]

I know our trucks run different at different sea levels .

I always wondered if the ambiant temp also may have an effect?

 

[Batman]

Big_Daddy_T

Would it be safe to assume that youget 13 mpg At least its consistant



TCoombs

Maybe that's why my mileage suffers, and my tires wear quickly?

George

 

[KatDiesel]

Couple of tanks -



The run I was excited about..... included driving to and from KC (185 miles each way), 8 dyno runs, and about 100 miles or so of intown driving. Calculated fuel milage - 17. 68mpg I added 4% to my milage reading for my bigger tires. Prolly could have been better if I didn't do the 100 miles of in town driving.



Last night - filled up drove to KC with a nasty head wind... it required 15lbs of boost to maintain 70mph most of the way. Lat time I made this drive it was mostly under 10lbs. Made 8 passes at the drag strip and started on my way home (filled up when the light came on since it was 2am) and this tank yielded 14. 78mpg



Not "Great" but certainly nuthing to complaina bout. We'll see how my milage does on my way to Denver.

 

[Sborri]

brobeson,

we are from the same area... beaverton here. i have 6speed HO with 3. 54 gears. mine seems to do the best 21-22mpg (according to trip computer) at 65 (around or just under 1900 rpms give or take). if i go over that it steadily declines. hard runs... . 75-80 will give me around 15. i only have 2800 miles on her... . and am hoping it will improve. i am a little concerned... because i am having a harder time getting the computer to show 21... . unlike a tank or two ago it was easy. wondering if it's the gas i put in it... or the temp difference????

 

[overfueled]

MPG

I spin 70 miles per day 1/2 back road 1/2 HWY I get 22. 5 mpg, on the overhead but I have found this not to be accurate. The real number is average 19-20 mpg. With 3:55 and 55-85 mph.