I see, you are one of those....

Did you get the breakaway switch back in, towing with brakes locked might give you bad mileage

I would also quit believing in the electronics and do calculations by hand, like 30 gallons for 450 miles etc, and be sure you actually drive the speed you mark and the distance you read, get a GPS.

 

I have no idea what you are talking about???? Must have been someone else....

 

ya i love the sites!!1 i will never live anywhere else but is kills the milage....

but no tow haul, i have a 6spd manuel. with 315 and the milage is hand calc with a gps nav deck. usually over 500 mile round trips.

 

https://www.dieseltruckresource.com/...d.php?t=194818

 

At just over 26k scaled, I get 10-12 mpg hand claculated. I cheat though, I drive a 12 valve, with a 6 speed and also have ems hubs (4x4). So I have mostthings going for me, I dont turn the front end, I run 80 psi in the tires, I also have the 6 speed and the 12 valve with 3.54 gears.

I did recently coat the exhuast , first the ats manifold, no real difference, but then I did the adapter / waistgate spacer (also wrapped it), both exhuast housings, and the intermediate hot pipe and wrapped it also. Mileage went up, speeds went up, and more 6 th gear use went up.

It fact I may start a thread about towing in 6th heavy. I try not to too, but it makes so much power now, I dont have to use 5th much, even on slight grades . On sunday, I pulled my usual grade (loaded) and crested at 66 mph. Its easy to pull in the 70-80 mph area now by accident. I down shift t 5th for the hills but it goes up at 60 + pretty easy at 35-40 psi of boost with the egts at 1250-1350.

 

The biggest issue with decent Trailer mileage is speed. If you are not on a hard schedule, 55-60 will give you your best mileage. Air up all tires on the truck and trailer to their max, this will help too.
A lot safer at these speeds too. You wil have no one in front of you. Passing other vehicles, not an issue. It may cost you 10 minutes per 100 miles to gain 2-3 mpg. At 3.75/gallon, is it worth it?
I get 12-13 mpg with a 12', 14k fiver, less with a head wind. The 4.10, are ideal for loads. I am turning 2k at 60, about 1750 at 55. 1800 works well for me.

 

I too have wondered about the same thing. I posted in another forum.

My truck is an 01 2500 4x4 qcsb Auto 3.54 gears. Only mods are an Edge EZ, 4" exhaust, ARE air filter and 305/70 Silent Armour tires (speedo has been calibrated). If I stay around 70 mph (1800 rpm) I get 19-19.5 when all highway. Average city/highway is around 15. When I haul my 37' 13K Toyhauler 5ver (55-60 mph) my mileage is around 10-12. My mileage amounts are not taken from the overhead but from the odometer and a calculator. Though I have calculated the difference and found the overhead to be off 1-1.5 mpg.

Sounds like my #'s are pretty close to most others.

 

Depending on my speed towing my 53' car trailer which fully loaded I have weighed over 20k lbs I get between 10-12 MPG.

Just the other week I wanted to see just how much my speed affected my mileage so I topped it off (right up to the top of the filler neck) and drove tops 72mph in the 65mph zones and 60mph in the 55mph zones brought it way down to empty then filled it back to the top of the filler neck MPG's were 10.6.

The next day I did the same thing except I did 65 MPH max in 65mph zones and also 60mph in the 55mph zones these were same roads, same hills, same weather temp, the wind is the only questionable thing and I averaged 11.7 MPG.

A gain of 1.1 MPG just by lowering my speed by 5 mph I would say thats pretty good on winter fuel towing lightest 7700 lbs (empty trailer) to around 21-22k (fully loaded 3 bigger vehicles on)

 

Considering fuel prices, I'd say a 10% gain is great!

 

Yeah it could really add up! Only bad thing is wind though you get stuck in bad wind no matter your speed fuel mileage is always going to stink. I mean lowering my speed is one thing I have done and will continue to do but I still want more yet whether a programmer, chip, downloader whatever just havent found one worth the money yet since thats what I would use it for would be better fuel mileage for towing.

 

Smarty on #1 should help

 

Unless you happen to get a killer tailwind!

 

my gross weight is 20,600 pulling a 5th wheel before mods i got 9.2mpg running 65 mph after the current mods i have the mileage up to 12.9 mpg at 65mph . trying more stuff now

 

we just got back picking up our trailer at the dealer for warranty work. the trip was 76 miles each way. filled up before and after at the same pump to the same level in the neck. $4.03 a gallon. we used the '03 with the edge on setting 1. we got 15.2 mpg. keeping speed to 65 or under and trying my best to keep it under 2000 rpm. the only time it went above that is a few passes and getting onto the freeway. this is hand calculated the overhead was reading 17.3...

 

Just got back from a 600 mile pull and like the guys in Oregon every which way you go is up.

I pulled my 28 ft 5er at about 60 mph with a CGVW of about 19,000 lbs. I took the same roads both ways and my mileage averaged 11.2 with 1 mpg difference due to winds. Going I had a light tail wind and returning I had a head wind. I know if I pull at 65 mph I loose at least 1 mpg. The cost of this trip of 600 miles was right about $240 for fuel and not counting the dinged bed rails and bent tailgate but that is another story.