real world mpg on duramax

[repoman]

i would like to hear from others on there mpg loaded and unloaded on there duramax.please list year and model and any mods.

 

 

07 chevy 3500 duramax/allison /crewcab/dually/longbed/4x4

i am getting unloaded average of about 15mpg

under 65 hwy about 17.5

over65 hwy about 14

towing a 12ft encosed trailer weighing about 3k loaded around 10.5 at about 60mph and about 8.5 at 70 mph abd above

 

so far only mods are cold air intake and cat back dual exhaust.my banks programmer is on backorder.my milage should improve when i instl that

 

i am a little dissapointed with my loaded milage so im looking for others to compare to. my lifted dodge with a banks kit got way better milage than this

[DSengineer]

How many miles on the truck?? Diesels take a while before they are good and broken in. Your mileage should continue to go up past 5K miles

[95Sierra2500]

I was gonna say, my dad's old 1986 diesel 1-ton dually crew cab 4x4 with a FOUR SPEED got 17 when towing a 28 foot fifth-wheel, almost 20 mpg empty. Something's dangerously wrong if you can only get 10.5 pulling such a small trailer. That or your diesel isn't broke in yet.

[Machine]

Hey there-

 

Let it get good and broken in before starting to worry about the mpg. All of my diesel trucks increased significantly in mpg after about 10K miles. My LB7 gets about 15-17.5 on the highway @ 70, 12-14 in the city, and 10-11 pulling about 10K#.

 

I run the Juice on top of a Quad programmer when just driving empty, and just the Juice on a tow setting when pulling. My sig has the rest of the mods.

 

Thanks

[repoman]

im just shy of 5k on the clock.i noticed an improvement unloaded with the exh,and airbox but i never towed before i instld them so i have nothing to compare with as far as loaded mpg

 

i will be towing a 40 ft toyhauler 5th wheel very soon.its weight loaded will be around 15-16k. i have heard alot of people getting 12mpg towing a similar rig.i was amazed that i was only getting 10.5 towing only 3k.i hope it improves after break in

[BlueFin]

I consistently get 20mpg unloaded on highway @ 60mph. Over 70mph I lose 1-2 mpg. Pulling a 4 place snowmobile/ATV trailer I get ~14-15mpg. I have a 2005 Sierra 2500 HD crew with 27,000 miles with no modifications. I run the full spec 80psi in the tires which is good for 2 mpg over 40psi from dealer delivery.

 

BlueFin

[CoastyAV8R]

Your dually, 4x4, longbed is the worse configuration for gas mileage, it's tall, bulky and long. It will get better as you break it in, towing loads also really helps diesels break in.