low fuel mileage

[Sean Marconette]

Do you have a tuner or exhaust mods?

I have a 2002 Dodge 3500 dually 2wd 6 speed manual and pull a heavy 48' LQ GN. My truck has an Edge Juice with attitude tuner with 4" exhaust. The truck has 4.11 gears and at 75-78 MPH it's turning 2200. I avg 10-11 MPG and have no problem pulling hills or passing slower traffic.

The tuner makes a huge difference and is like night and day on my truck. The attitude gives you the ability to see boost, EGT IAT, and the ability to switch up to 5 modes. It was well worth the money.

Sean

[Hacksaw]

I have a Bully Dog. Tried 3 different modes and either one seemed to effect mileage only perf. Recently fried the auto trans and since the rebuild I have not used the tuner. It's got 4" exhaust.

[Hacksaw]

So is 10 mpg all I should expect? I've heard claims of 15 mpg.

[Sean Marconette]

I thought maybe someone else would chime in?? The best mileage I get with mine not towing is 18-21 MPG, at 75 to 82 MPH, turning 2200 to 2400 RPM. My truck only has 114,000 on it. To be quite honest with an Auto and yours being a 03 that's seems like a reasonable number. If someone is getting 15 MPH there is no way they are pulling a 22,000 lb trailer!

[Mike Pearson]

Originally Posted by Hacksaw

So is 10 mpg all I should expect? I've heard claims of 15 mpg.

That's about what you can expect from that truck. I have had numerous diesel dually's and they all get about the same mileage. 9-10 towing a big heavy trailer. Mine weighs about 16K. you might get a bit more if you have a tail wind of tailgate a semi. My buddy has a 5.9 dodge and it gets about 10 - 11 mpg right next to me. I have had Fords and Duramax. They all get the same.

[Hacksaw]

Did an accurate check of fuel mileage from this past weekend. Drove some hiway at 65 mph and some back roads at 55 mph. The math says 9.7 mpg.

[David Lee]

Originally Posted by Hacksaw

I have a Bully Dog. Tried 3 different modes and either one seemed to effect mileage only perf. Recently fried the auto trans and since the rebuild I have not used the tuner. It's got 4" exhaust.

what do you get when not towing. I have the 99 version and get between 17 and 19mpg

[Hacksaw]

Sean: The truck and trailer total weight is under 22,000 lbs. Rarely use the truck without the trailer, but if the overhead indicator is at all accurate I'm over 21 mpg.

[jmcarter]

Based on my experience with two 5.9 Cummins (both with manuals) 10.5 MPG seems reasonable, particularly towing 70. Have you tried towing at about 1500-1600 RPM? You're likely to get 2-3 MPG improvement and then you can do a cost analysis to see if a gear change is reasonable.

BTW your indicator is probably optimistic by at least a couple of MPG. Also, unless you plan on burning up another stock auto best leave the tuner stuff unhooked.

[Bob Mulry]

Hi Guys,

Took a long road trip (Topeka, Indy & Earlville) from Northern California to Indy and back, which totaled 6100 miles.

My tow rig is a 1999 Dodge Ram 3500 CTD with DRW, 5 speed (now 6 speed) 2 wheel drive, 3.55 rear gear and a 28' Pace Shadow trailer with a combined loaded weight of just under 21,000 pounds.

The trailer is a tag with no additional height which helps keep it out of the wind.

The only non-stock items are a 4" exhaust, exhaust brake and a K & N air cleaner element.

Driving at 65 mph most of the time we averaged 13.1 mpg for the entire trip. I think that keeping the trailer low enough that it's out of the wind is a big help to the mpg.

As an added note the change from a 5 speed to a 6 speed, later on was a welcome addition to improve the driveability of this truck while towing.

My truck now has 224,000 miles on it and still gets right at 20 mpg not towing

Just my 2 cents,
Bob

PS:
Now to find the quietest straight through 4" muffler made.