Fuel Mileage

[JohnBower]

Just went on a 2400 mile trip from Phoenix to about 100 miles east of Oklahoma City towing my 29 foot travel trailer and only got 11 mpg average for the whole trip. Speed was 60 mph on I-40. I really think this sucks. How about everybody else?

 

[sam-eye-am]

That is about what I got towing an 8. 5ft wide 24ft long enclosed car trailer. Trailer loaded weighed 10k. Had one bike on top of the cab high camper shell. Towed just over 3k miles form coastal VA to Santa Barbara and then up to Monterey. I think my average was right at 11 mpg (hand calc) doing 65. That was in August, so prior to the G30 recall. My unloaded fuel economy has improved (as far as I can tell as I haven't had a full tank unloaded since December) since the G30 recall, but haven't dragged the car and trailer anywhere since... .

 

[jimnance]

Shoot, when I was pulling a 33' toyhauler with my '03 CTD six speed about the best I got was 11 MPG. I really don't think that's bad. Pull that load with a gasser and you'll probably see 6-7 MPG. Also, the CTD will be running away from most gassers on the hills.

 

[Vaughn MacKenzie]

My '98 12-valve 2-wheel drive shortbed should have everything going for it, but gets only 11-13 pulling my 20-foot travel trailer at 63-65.

 

[PRout]

Can almost always count on seeing 12 to 12. 5 pulling a 28' 5th wheel at just over 17k gcvw with a 2000 5. 9 4x4. But yet she refuses to surpass 19mpg empty. I want to be one of the ones that sees 22 mpg's with their 4x4. .

 

[icman95]

Sounds about right to me. In fact, I'm jealous. 10. 5 is the best I got towing my 33' toyhauler at 21,500lbs combined weight with my '01. This was at about 60mph. The worst was 8. 3 mpg, but was, umm, NOT at 60mph. :-laf

 

[Hoefler]

I had about 2,000 miles on my 08 auto when I made my trip to Mass. and back pulling my loaded enclosed 7. 5' x 16' trailer, 3400 miles round trip, I averaged 75 mph, and got 10. 8 mpg hand calculated. That included spending 3 hours trying to get the last 45 miles because of the interstate being block by a big rig on its side. Got off the highway and crawled from town to town trying to get to Hadley, Mass.

 

[DPKetchum]

Pulling a 3 horse living qtr trailer I get 11 to 12 at 65/68 mph. My last gas burner got 8. 5

 

[HBarlow]

John,



Your signature doesnt' tell us what truck you own so it's hard to evaluate your situation. That's a pretty typical fuel economy report for a Gen III truck pulling a fifth wheel. 12 valve owners report a little better but probably not by much.



That's 2 or 3 mpg better than a Navistar or Izuzu engine can do. Don't be influenced by the "exaggerators" who you meet at the fuel pumps at Flying J. Anybody with a Ferd or GM who tells you he is getting that or better is living in a dream world. Likewise any Dodge owner who claims to be getting much better mileage is dreaming also.



It is possible to get better for one or two tanks of fuel on a rare occasion with a strong tailwind but 11 mpg is reasonable.

 

[DPKetchum]

I pulled less weight with my 12 valve and gutted on big inclines etc. It got a pretty steady 12.

 

[jimnance]

John,



Your signature doesnt' tell us what truck you own so it's hard to evaluate your situation. That's a pretty typical fuel economy report for a Gen III truck pulling a fifth wheel. 12 valve owners report a little better but probably not by much.



That's 2 or 3 mpg better than a Navistar or Izuzu engine can do. Don't be influenced by the "exaggerators" who you meet at the fuel pumps at Flying J. Anybody with a Ferd or GM who tells you he is getting that or better is living in a dream world. Likewise any Dodge owner who claims to be getting much better mileage is dreaming also.



It is possible to get better for one or two tanks of fuel on a rare occasion with a strong tailwind but 11 mpg is reasonable.

I've got a buddy with a Dura-Max and he get's very similar mileage to mine. Maybe . 5 MPG less though he is about 2,000 lb lighter. He's about 21,500 while I'm 23,500 with my 37' fifth wheel. I'm right at 10 MPG and he's around 9. 5. The only time I've pulled on nice flat terrain I got about the same mileage, but I was running 65 MPH and my fifth wheel grabs a lot of air. 11'8" tall and 8. 5' wide

 

[SoTexSmokin]

all of yall are lucky empty my 08 mega cab gets about 10 or 11 pulling my cow trailer loaded with 13 to 15 cows im lucky to get 7 and the dealerships says there is nothing wrong!

 

[PRout]

Yeah, I dont understand where the extra wasted energy is going. . Up in smoke? Heat? There seems to be a lot of difference in people's numbers, but those losses have to go somewhere. I've always suspected there are a lot of variables in odometer cal, are they driving with the wind, downhill both ways, tire drag/inflation, people's methods of calc'ing, 4x2,4,6, lifted/lowered, covered bed, big mudflaps, mirrors, wings, parachutes, etc. Just cant see one truck getting 23-24 and another getting 11-13 and not seeing a major obvious energy loss or problem.

I agree w/ HBarlow, lots of dreamers out there. . (flame suit on - hehe :-laf) yes, youre dreaming! or PROVE IT with some real stats in a spreadsheet and some indication of how you have verified your odometer cal.

Have been saying for yrs, 18. 5 avg best - High 19's TOPS cruising, sometimes 16-16. 5 in the city, got 14. 5 w/ the in-bed pop-up camper (noticed just removing the jacks made a difference in drag), 12-12. 5 w/ a 5th wheel (one trip pushing major headwinds for 300 miles saw 9. 5, but normally 11-13 towing). And I've changed lots of s*** (that's stuff) trying to break 20 empty.

24 or above. . ha! ha! ha! (where's that suit. . )

 

[csavard]

Just beat 20MPH!

I just took my megacab on its first post-mod highway trip. Took it on mountain roads for 385Km and watched the overhead climb steadily. I was running loaded with only the 5th wheel hitch and two buddies.



The overhead topped out at 20. 5 MPG and since returning to the city it is staying between 19 - 19. 6 MPG. I took it out for a run with the 5th wheel trailer (9K) and never saw the overhead drop below 19 MPG. I am so thrilled with this truck.



The mods were 100% worth it & I have no regrets for the $ spent. With just under 7000 Km on the beast I can hardly wait to see where the millage gains will top out.



Now to convince the wife to let me add the FASS lift pump !



Yukon Chris

 

[HBarlow]

The overhead calculator displays a number based on all driving since last refuel or reset.



I could reset my overhead, drive 120 miles at 55 with a tailwind, hook up a heavy trailer and drive 20 miles and consult the overhead and be thrilled to be getting 19 mpg at 24,500#... ... . if I enjoy deceiving myself.



Try resetting the computer when you hook up your trailer and post again.

 

[donnandon]

Just my 2 cents worth... . you have to compare apples to apples! The guy driving a Regular Cab 2WD manual trans w/3. 53 gears will get better mileage that I will driving my 4x4 Dually Auto w/4. 10's! Thats just common sense.



We pull a 39' 13k 5th wheel and get approx. 10mpg on average hand calculated. Do I care? NO! That's way better than my gasser was towing half this size trailer (7 mpg). And not too many hills or mountains slow me down any more!

 

[csavard]

Thanks for the explanation HBarlow, I will reset my computer today & see what happens.



Yukon Chris

 

[icman95]

With a modded truck I would be wary of the overhead anyway. It is calabrated for the stock setup and fuel flow. When you change these things with aftermarket stuff the computer doesn't know how to handle it and gives a false reading, usually way too high. My overhead says 28 mpg towing a 33ft 5er. Obviously there's no way that is happening. Use the tried and true method at the pump when you fill the tank. Doing it by hand takes a minute or two extra, but is as accurate as your math.

 

[CEly]

Just returned from a week in the Black Hills SD. ) 08 Mega cab, 4x4, dually, 6sp auto, 3. 73 gears, 40' toyhauler and winds in every possible direction, average speed 65-70 MPH and got a low of 8. 0 MPG & high of 8. 5 MPG hand calculated. Pretty much the same mileage as my old 02 PS with the 7. 3, but WAY more power! Love that Cummins torque curve!

 

[PRout]

That sounds like a heck of a rig. . And still got 8-8. 5 with plenty of power. . Gotta appreciate that. I remember when my friend was complaining about his 454 chevy dually taking 25 gallons to pull his trailer a hundred miles. . Yeeouch!