First time with the 2004.5 truck pulling a 4 place enclosed trailer and I was shocked at how poor the mpg was - 8.9 MPG!, computer showed 12 to 12.5 but I typically don't even bother on looking at that.

Truck details - 2500, automatic, 3:73 gears, 265 / 70 / 17 tires at 85 psi, 7' by 8' flat bed made of steel, probably adds 500 to 600 lbs over stock. Muffler delete, cat still in place. No chip, No winter radiator block. One thing to note, I had to charge the battery for 1/2 hour before we left since we just got done finishing the installation of the truck bed over the last two weeks. I think sitting along with going in and out of the truck with the doors open while we worked on it drained the batteries.

Trailer details - 20 foot box with 4 foot V therefore 24feet long. Wide trailer, I think it is 102" wide, all aluminum frame that weighs 3000 lbs empty, sleds & gear add around another 3000 lbs. Height - here is the kicker, 9.5 feet tall from memory.

Driver details - used the cruise, set at an actual 70 to 72 mph, the tach read 1950 rpm to 2000 rpm.

Outside temperature on the way up was -4F to -6F, on the way home, typically 20 to 25 F.

Does the mpg seem right? From memory, my friends 99.5 ford powerstroke with 33 tires get's 10 to 11 mpg with him driving it; no cruise and always on the throttle.

Please let me know your thoughts or suggestions. I was expecting 11 mpg at least, hoping that the CUMMINs would do better than the Ford or Duraminimum that we sometimes use.

Scott

 

Seems a little low... Were you bucking any winds when towing? I pull a 27 V nose enclosed 102 inches wide at about 9K lbs. I think I average 10 MPG, but this trailer is not 9.5 feet high. i am sure the winter weight diesel is not helping out as well...

 

Sounds about right for winter driving especially @-4 F . I haul my boat in the summer at about your dimensions, 24' cuddy cabin @ #6500. What most likely go you was killing you 1)----the temperature (gear oil real thick in axles) 2)----no winter front ( not getting to operating temperature for a looooooooog time hauling a heavy load while warming) and 3)---did not mention in your post but I assumed you had some idling time in there also. In the summer I can crowd 13 mpg with a/c and cruse 70-73. I dont think any diesel will pull good in those conditions when below zero without loosing at least 10% efficiency. I only have a small opening in my winter front and it still takes a while to warm up. Just my $0.02

 

I have an Interstate Sno Sport. It is a 20' box with a 5' v-nose. It's about the same as yours being on top of the axles. It's inside height is 6'6". I pulled it this weekend again about 130 miles and I usually get around 12.8 but this winter fuel is killing me and I have been getting about 11.5 like this weekend. I get better mileage towing my toy hauler that's taller and heavier by quite a bit. I even use additives for cetane boost but it doesn't do much to get me back to staight #2 numbers.

 

"here is the kicker, 9.5 feet tall from memory."

Well, theres your problem
Thats pretty tall, but I would think it would get a tick better than that. IF it was me, I would first replace trhe fuel filter and tow again. Add some cetane booster for fun too and see if that helps. It always helped my 99 alot. Also, winter blend SUCKS!!!

Also, make sure the tires on the trailer were aired up all the way. That makes alot of differance with my big trailer

Chris

 

Like Chris said that's a wall your pulling!!! My truck and trailer weigh in at 19k and I get 14.5 to 16 but I have a few supporting mods!!

 

Also my sweet spot is between 60 and 65 at 70+ my milage suffers even unloaded

 

Thanks guys for your advice.

Regarding the tires, they had quite a belly in them but did check out at 44 psi. We are running car tires on the trailer, 205 / 75 / 15 from memory. I know we "should" be running trailer tires, but it ended up being a $$$$ thing. Maybe the tires should be cranked up to 55 psi as well as closing off the front grill.

Do you guys suggest blocking the intercooler or blocking off the radiator only?

Also, luvncumns state he has "supporting mods", what mods do you suggest that I purchase? I am seriously considering the 3:42 gears, for the improved MPG as well as a bit quieter. I know I will never get my $$ out of it but I just want to do it.

THanks for all the responses.

Scott

 

If it's a 4x4 I'd go to a taller skinnyish tire instead of doing gears. Cheaper and other added benefits you might not care about.


That's all I'm gonna suggest besides saying that I think two things are probably hurting you... A tall trailer and I'm thinking you might have been in a head wind. Even a light one can kill your milage by a couple or more MPG. We just experienced this in an unloaded truck coming back from a hunting trip in Kansas in an F150... Couldn't believe we lost 3 mpg on the way back from a headwind all the way back. We were only getting around 13-14 mpg on the return trip instead of 16 on the way up.

 

you go to taller gears and you will lose more. It will be harder to move the mass requiring more fuel during pulls. Keep the 3:73's and maybe start the bombing.

Let that big dog breathe. Intake, 4" exhaust maybe a mild chip if you want to keep it easy. Edge easy?? If you chip, pyro gauge at least!! You will get more from those mods than a gear change. I really believe the 3:73's are the optimum gear for tow and around town driving.

Chris

 

I just bought the winter front from the dealer, it's about $100. It covers the whole thing up front but has a 12" opening with (4) flaps with velcro. Above 30* F I normally have all the flaps open. When temperatures stay above 50* I remove the whole front. You could do the same with cardboard , cover the front but cut a 12" square in the middle. This will allow air to the fan in case more cooling is needed. My water temperatures get up to 200 pretty fast in the winter and pretty much stays there, if temperatures rise and I forget to open spme flaps up the water temperature may go 1/2 a needle above 200 and drop to 200 off and on.

 

Car tires on your trailer will hurt mpg ALOT. They are much softer sidewall and have more rolling resistance. Otherwise, your mileage will suffer bigtime due to wind resistance of the trailer as well.
I pull a 2-3place single axle aluminum enclosed Vnose sled trlr and get at best 13-13.5 mpg on the highway 75-80 mph. With a nasty headwind I only get about 10mpg. This trlr is only about 3klbs total weight.
I can pull my ski boat, about 4500lbs at the same hiway speeds on summer fuel and get 14mpg+ with it. Less wind resistance and summer fuel.
Not much to do about wind resistance and winter fuel, but the car tires gotta go. Aside from being inefficient for towing, they are not as safe as trlr tires. Over the years, I've seen many more car tire blowouts on tralers than those w/ trlr rated tires.

 

As far as blow outs go:

That's because everyone uses car and LT tires on their trailers . I know I do, but don't pull them often enough for it to matter about mpg.

Just free or next to it take off tires that are structurally good and have adequate tread.

If I had a new trailer or one I pulled on a regular basis I'd get the proper tires.

 

Regarding tires, yes, I want to get the 235s available for the truck, I think they are the same diameter as my 265 / 70 / 17. If someone knows of taller and skinnyer tires than my stock 265's, please let me know.

Chris - truck has 4" stock, but yes, the kitty has to go and replace with a magna flow muffler or equilvant. Regarding a chip, I noticed quadzilla just came out with a chip that is meant for fuel economy, fuelmizer I believe it is called. I may try that one. What can I do with the intake? I just bought a big honkin air filter, is there something else I can do to the intake?

 

Hello,

I think the lack of a bed coupled with the size of the trailer is a drawback. The flat bed is hurting you to get the air up and around the trailer.

Damon