What am I doing wrong? 4.1 mpgs!

Joined
May 9, 2016
Messages
66
Location
Denver
Granted I’m towing ~6,000 lbs with wind but WTH?

Currently driving Denver > Albuquerque > Grand Canyon > Vegas > Moab but barely making it between some pumps.

Otherwise the tow experience is great for a non-HD truck but this seems a bit off....

BTW the trip odo is showing the full trip not the tank.

1615697400645.jpeg
 

bloc

SILVER Star
Joined
Sep 19, 2008
Messages
9,617
Location
Central Texas
Hand calculate it to verify the readout. Usually it's pretty accurate but I wouldn't bank on it.

As for if it's actually that bad.. 6k pounds, but what is it shaped like? Other than up hills wind resistance is the big horsepower and therefore fuel hog. Huge wind sail of some kind? Tire pressures good? (including the trailer).
 
Joined
Apr 27, 2011
Messages
7,515
Location
San Diego
Agreed something doesn't seem right. How many miles to a tank do you get?
 
Joined
May 9, 2016
Messages
66
Location
Denver
Best I was able to get by hand calculation was 7 mpg which was about what computer was telling me during that particular stretch.

Trailer is 23ft long by 11 ft tall - outdoors RV 21DBS. It’s slightly taller than most trailers but not by much. Cold tire pressures are 42 F and 44 R.
 
Joined
May 9, 2016
Messages
66
Location
Denver
Not sure what full tank range is because I’ve been too nervous to go more than 100 miles between top offs.
 

radman

SILVER Star
Joined
May 28, 2019
Messages
1,816
Location
Houston
Keep in mind that you have a good 4.5-5 gallons to go once the ECU says 0 miles to empty. Most recently, i filled 19.5 gallons after driving 12 miles past 0 ( I average 10.5 in the city).
 
Joined
Nov 6, 2009
Messages
503
Location
BC Canada
Towing my '25 ft Keystone i get 300 km's (180 miles) per tank. How fast are you going?
 
Joined
Apr 27, 2011
Messages
7,515
Location
San Diego
When I ran with 33.2" tires and an 8k trailer, albeit with slightly better aero... worse mileage going 70+mph in wind was probably in the 8 mpg. Never in the 4 or 5 unless climbing ridiculous grades, but that generally doesn't last for the tank. About 180-220 miles per tank, leaving 4-5 gallon reserve.

Same question as @GordJ, how fast are you travelling? That's prob the single largest variable. Also what gear?
 

Markuson

SILVER Star
Joined
Jun 15, 2008
Messages
11,293
Location
San Diego via all over-
Best I was able to get by hand calculation was 7 mpg which was about what computer was telling me during that particular stretch.

Trailer is 23ft long by 11 ft tall - outdoors RV 21DBS. It’s slightly taller than most trailers but not by much. Cold tire pressures are 42 F and 44 R.

Those are pretty painful numbers. :(

Wind resistance is a massive factor with our 200s. Is your trailer basically this?
D7C4D63B-F16E-4AB5-841A-A75F0FF7B263.jpeg

If so, I’n not quite as shocked...especially at higher speed. You’re probably 12,000lbs including an 11ft tall sail in front, with a big square in back at highway speeds.

Just the weight and poor aerodynamics of my built, bumpy 200 went from 19-20 mpg highway (mild lift, AT tires & sliders) to 11-14 (fully built, bull bar, rear swingout tire, and more) highway largely because of wind resistance at higher speeds.
 

afgman786

SILVER Star
Joined
Feb 19, 2013
Messages
3,936
Location
Gainesville, VA
Your picture shows you're in drive. Are you actually in drive or in S mode in your 1 to 1 gear? Besides speed being a factor and how big that thing is, I've noticed if in drive it burned a bit more gas for me when towing compared to keeping it in 4th
 
Joined
Jul 29, 2013
Messages
1,858
Location
Knoxville, TN
Drive right behind a semi to save mpg. Just radio the driver you’re hitching a ride in case he brake checks you. 😎🤣
 
Last edited:
Joined
Mar 28, 2006
Messages
1,699
Location
KC (Lenexa)
11' tall combined with wind is a killer, and potentially the speed you are trying to drive.

I remember going across KS into a headwind towing a 8x16 enclosed. Going into a 30mph wind I was lucky to get 6...and that was at 60 mph
 

Sandroad

SILVER Star
Joined
Jan 31, 2009
Messages
4,118
Location
Michigan
Since you’re in the middle of the trip, drop the transmission into 4th gear, drop your speed to 55-60, hand calculate mpg, and report back. It’s windy out west now too, which whacks mpg if it’s a headwind.
 

WCDAVE

SILVER Star
Joined
Aug 14, 2020
Messages
236
Location
PA
Curious as to what the OP expected the MPG to be? In stock form the MFG MPG figures are 13/17 and pretty much accurate. Then add an eleven feet tall and 7+ feet wide and 6,000+ pound trailer to the lifted truck with larger tires ...... was the thought that this would just shave a couple of MPG towing in the mountain west? The trailer weighs more than the Cruiser after all.
TFL tested this with a lighter and smaller profile trailer and was in your MPG ballpark.
 
Joined
Dec 27, 2015
Messages
797
Location
Reston, VA
I towed my 40 cross country and seen similar (~4-5mpg) running from Yuma to Flagstaff. My issue was the insane elevation change. Once it flattened out I was back in the 9-10mpg range
 

linuxgod

SILVER Star
Joined
Jan 17, 2016
Messages
5,191
Location
Chicago, IL, USA
tl;dr - start with running a few tanks of premium as you're towing on this trip, preferably ethanol free. Engine might have retarded the timing and it will take a few tanks before the ECU recalibrates. With your setup I'd expect you to get about 7MPG, give or take depending on terrain, speed, etc.

If you got 4MPG over an entire tank, driving at 60mph like your speedometer shows, that seems very low. Note based on your tire size you are probably reading 3-5% low on MPG and MPH, but 5% ain't much.

What gear are you towing in? For your 2013 it should be 4th

What fuel octane? Did you fill up with 85 at elevation and now you're lower where the knock sensor is kicking in? I never run <87 even in the mountains as I've had the engine retard timing and I can feel the lack of power and will get 5.5-6 MPG when that happens. I've also seen this with bad fuel where I went from ~7 MPG to ~5.5 MPG in one fillup.

Ethanol fuel will hit your MPG when towing by 5-10% in my experience, so if you can find ethanol free when towing use that.

Uphill in the mountains I'll get about 3 MPG. That's pretty short stretches though, like Monarch or Vail Pass where you're in 2nd gear and revving 4000-5000 RPMs. Average in the mountains is between 6 and 8 for me depending on the terrain, as overall elevation nets you a bit better mileage as you trade off power due to the thinner air

Typical for me with a 6000# trailer that's 10' tall (including the A/C on top) I get between 6.5 and 7.5 MPG if I'm on the highway cruising 70-75. Hills and speed hurt mileage. That MPG is adjusting for tire size, BTW, so the dash reads low 6s to low 7s.

I do keep a 4.5 gallon rotopax on the truck for emergency use, as there are some stretches out west (like west of Moab) where it's 100+ miles between fuel stops.
 
Joined
Nov 6, 2009
Messages
503
Location
BC Canada
Its funny, the very best mileage that I ever had towing was on the Dempster highway in a rain storm. The road was very, very muddy and slippery, a natural gas tanker slid off the road and it was closed for 3 days, and the traffic was bumper to bumper for miles and miles and top speed was 60 KM/H (40 mp/h) and I was able to travel from the Klondike turnoff to the gas station which was 370 Kms. I had never been able to go more than 300 Kms before or since and I'm not able to duplicate it to confirm those numbers because there's no way I am ever going to drive 60 Kms for more that 10 minutes unless forced to by nature or man. I estimated at the time that I was getting around 15 mpg canadian gallons.
And I drive on reg. gas, cruise control and in Drive just like Alfred Horner Munro intended.
 
Joined
Feb 27, 2018
Messages
1,428
Location
Alaska
My camper is very similar to yours. ORV 22 BHS, and I have a ‘13 LX. I average 8-9mpg running <60mph all over AK. Worst I’ve ever seen on a long trip is one time to Seward had a 40-60 mph head wind most of the way and got 6 mpg.

and I only run ethanol free gas.

and I run ECT in power and transmission in S4.
 
Last edited:
Joined
Jun 28, 2019
Messages
361
Location
Littleton, CO
Maybe I'm being Captain Obvious.

The RPM gauge is your friend. Like others said above, If you're going into a headwind then slow down. If you're stomping on the accelerator from a stop then consider moving your rig and trailer slower as you move towards cruising speed. Consider using a fresh engine air filter on your trips and use it only when you're towing. Then swap it out with another one when non-towing. When we hit the 4x4 trails I swap the air filter for an older one so as not to dusty-up a clean one. Change the plugs if needed.

Two weeks ago I returned to CO and had a strong headwind all the way across KS. I slowed highway speed from 75 down to 65. Made a huge difference in mpg and especially the noise factor. If your pushing the RPM a lot into high ranges, consider driving that it keeps the RPM's lower and consistent. But I'm sure you know all of this.

Air pressure is a big factor. The lower the altitude the more air resistance you will have. The colder the ambient temperature is then the more air resistance you will have. The less humid is the air then the more air resistance you will have. Hard to believe but cold dry air is more dense than hot humid air. But this explains how severe storms in the Midwest and South are created - the cold dry air coming down from the Rockies is so heavy that it pushes the humid hot air in the Midwest/South up into higher altitude. This is why my rig obtains higher MPG in the CO mountains than around the Alabama beaches.
 
Last edited:
Joined
Jan 23, 2019
Messages
1,825
Location
USA
If it was me first thing I would look at is the air filter. If it is clogged with dust, that would do it.

The other thing is if the ECT switch is on you get worst mpg.

Never follow a big rig up close to draft it, you may get better mileage but the down time replacing a windshield or rock chips in the paint doesn't make it worth it in IMHO.

I would watch at what RPM it shifts nearest the speed you want to travel. When the engine is cruising it gets the best mileage, meaning not revving too high and not lugging it.
 

Users who are viewing this thread

Top Bottom