I've had this truck about a week, but this was the the first time I've ever used it pulling a load on a long trip.When I went four wheeling in San Antonio this weekend I had what I would think is bad fuel milage for a 12v cummins dually. The trip was about 200 miles from Corpus Christi to San Antonio. I was pulling about 7000 pounds. I had a buddy's Suzuki Samurai in the bed, a trailer, and my Jeep on the trailer. I got 11.5 mpg, going mostly 65-70 the whole way. Boost was right at or just under 10psi and pyro meter ran pretty much at 800-1000 the whole way there. Would this be considered normal, or is this poor. I know the truck has been modified with homemade down pipes and exhaust, but I was wondering if the fuel pump was turned up too much and it was just suckin diesel down. I especially thought I would get better milage because I have 3.55s in the rear axle and a 5-speed tranny. I'm also getting lots of black smoke at acceleration, usually when boost reaches 20-30. I know some smoke is normal, but just wanted to know what everyone thinks. I always hear how people say their Cummins get 16+mpg towing, so I was just wondering what everyone thinks.

 

That really doesn't sound bad to me. The wind moving through your load instead of around it like with a travel trailer wil kick the heck out of your mileage. Its a good load with ugly aero properties. Just my .02.

 

[quote author=greatwhite link=board=9;threadid=18247;start=0#msg171046 date=1060606573]
That really doesn't sound bad to me. The wind moving through your load instead of around it like with a travel trailer wil kick the heck out of your mileage. Its a good load with ugly aero properties. Just my .02.
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Yeah, the Samurai stuck up a bit high. ;D

 

Just as a comparison just got back towing my 25 foot boat to the keys and back and averaged aroung 12MPG for the trip averaging 70 mph around 8psi boost and 800 or so for the exhaust temp.

 

Pulling four Vehicles down the road at 60-70 mph, and getting 11.5 mpg! what type of milage do you want? I know some terd and chubby guys that would kill to get that empty

 

The guys who claim they get 16 mpg towing a 5er are old farts who drive 55...











in the left lane with one blinker on.
BTW, I think it's funny that the Samauri fits in the bed. That picture is a hoot.

 

Thanks guys, I know this is considerably better mpg than the gas trucks get, I just wanted to make sure this is normal since I hear all those "20mpg stories"

 

Hey Blake,
I was looking at the picture of your rig and wondering how the Samauri is secured. It could be really unpleasant to get the bumper in the back of your head in an accident. I don't think the headache rack would slow it down much.

 

What type of diesel you running. I try to find Premium when I can. I notice that I get more smoke with the cheaper stuff.

Also I run a cetane booster most of the time. I have a 2003 VW TDI and the engine was desinged for 50 cetane the best I can find is 45. If I run the 40 stuff, my milage goes down, it doesn't run as well when it's cold and it smokes more.

Next time you do a heavy load, try some cetane boost if even you only use it when your hauling I think you will see a difference.