MPG for 2013 Duramax?

[elkhornsun]

Originally Posted by RetiredFPD

The only way you'll get a noticeable mileage change is if you do a complete system change on it, i.e. turbo back exaust (at least 4" - 5" is better), a good programmer, or better yet a pre-programmed ECM, a cold air intake, and good syn oils (all of em). There are many good systems out there, but Kennedy Diesel for an ECM, or a Banks system are the best around. I'm running a Bullydog GT, 4" exaust and cold air intake on my 2007 6.6 dura LBZ and I regularly get 23-25 on the highway empty, and 13 towing a 15k FWTH (no water). Two things will kill you on that '13, well, aside from it being a dualie (more rolling resistance). The cat and the DPF. Get 'em off there if you can (exaust system change), depending on what state you live in. If CA, you're screwed. Just FYI, I beefed up the bed carrying cap of my 2500 with bags and shocks, and it'll carry anything the 3500 will, bed wise. (Same truck, just two extra tires/wheels). The two extra tires give you a bit more CC, but not enough to warrant the extra money...and a dualie is hard as hell to park and you can't run it thru car wash lol!

What garbage. The OP is getting a 2013 LML powered truck. Your experience with a LBZ is not relevant in the least. The LML already will provide 20 MPG without spending thousands of dollars to turn a pretty clean running engine into a mass polluter like your truck. The LML also produces about double the torque of your LBZ engine so it is hardly hurt by its DPF and DEF emissions control systems.

Why do people think polluting the air people breath to save a few bucks is a good thing. It is neither ethical or legal if anyone cares about either anymore.

[RetiredFPD]

Not unless you make some changes to the truck i.e. lose the DPF, Cat, get a good programmer or ECM, cold air intake, etc. If you go stock there will be no change but I recommend you put some gauges on it to keep track of your EGTs and Boost. The worst thing they did to the Dura was the DPF. Really hikes the EGTs when towing.

[Barefoot68]

I. Have a 2013 Duramax and get 21 empty 11 to 12 towing that's hard to beat.

[Vette Racer]

Originally Posted by Barefoot68

I. Have a 2013 Duramax and get 21 empty 11 to 12 towing that's hard to beat.

I think some of you that quote the big mileage numbers don't pull the weight others do, in my case 9 mpg is about as good as it gets but that is pulling 29,950 lbs gross combined weight (cat scaled) at 62-64 MPH over a long trip, in other words, an average figure, sometimes more, sometimes less. With the power these new trucks have, I'm a happy camper.

[FreeByrd]

Just traded our 2WD 2003 Dually last month for our new 2013 CC DRW LB D/A 6x6 with most every bell & whistle we could think of that we wanted.

We pull a 2006 3 axle KZ Escalade 40' Toyhauler with 2 Harleys (rated at 20,000 lbs) that crosses the scales at just over 19,400 lbs. . . plus the fully loaded truck. . . so we're over 29,000 lbs.
We've been full time RV'ers for going on 6 yrs and this thing is a MONSTER when it comes to the amount of torque and horsepower compared to it's 10 year older brother. Don't get me wrong, in 2003, the Duramax with an Allison transmission was the strongest combo out there. Got 11.5 mpg towing and 21 mpg on the interstate @ 65 mph.

The new truck with 52 miles on the odometer, was getting 17.5 mpg on the ride from the Kansas City dealer where we bought it back to Omaha on the interstate doing 70+. Been averaging 10.3 pulling the RV through the rolling hills of Missouri and Illinois over the last 5 weeks. Which is not bad for a EPA laden vehicle that provides this kind of lifestyle!

It really just boils down to preferences. . .
the 6.7 Ford is a giant; the Ram Dodges have 850 ft. lbs. of torque. . .
but I'd rather have the Silverado. . . . which is just my preference.

Hope to see you out there !
Mike

[Barefoot68]

I hope you listen to manufacture and broke it in right. If you started hauling before 500 mile break in you might start having issue with seals in rear axel. I put over 800 on mine staying under 60 and no towing. Now I get 21 empty and 11 to 12 pulling 13,000 Columbus

[jamesrxx951]

Originally Posted by Barefoot68

I hope you listen to manufacture and broke it in right. If you started hauling before 500 mile break in you might start having issue with seals in rear axel. I put over 800 on mine staying under 60 and no towing. Now I get 21 empty and 11 to 12 pulling 13,000 Columbus

The seals do not see any drive line loads at all. The bearings are all "preloaded" to a certain torque so all axle components are "locked" into place. The seals are there only to prevent the fluid from escaping. There is no break in period for seals at all. If there was, there would have to be a warning when replacing them to not tow for 500 miles. The 500 breaking period is likely due the brakes wearing in and allowing the engine and transmission control modules to start their base adaptives. This also allows some time for rings to seat.

[Scottybdivin]

I drove my 2007.5 for 186K mi. It was an incredible truck, never used a drop of oil. I can't believe some of these numbers I am reading. I logged every gallon of diesel that the truck used and still use the same log book for the new truck. Towing 18K toy hauler fully loaded 8 mpg on flat ground and no wind. Empty, 13 mpg on every day driving, 15 on straight interstate highway. The truck wouldn't do 20 mpg downhill with a tailwind.

[FreeByrd]

Got 11 mpg pulling the Rig from Shipshewana, IN to Lansing, MI yesterday. The LB7 was average 11.3 to 11.8 depending on the terrain.

When we picked up the new truck, the Dealer said, it wasn't necessary to do less than interstate speed because of the Alison 6 speed. The rpm delta between 60 & 70 is pretty small. . . but didn't tow till I had just under 900 miles on it. (I read the book too) They did say to vary the speed on the ride home to help seat things, which I did for the 900 miles.
I also changed the oil & filter after 1500 miles and will now follow the DIC % information.

Was also getting a tad over 21 mpg running 55 mph on a 2 lane road "out in Amish country" on Saturday. Seems to be working fine.

[Iowa6.6]

I have only had my 2013 chevy dually 4 weeks. Combine weight is 21750 - not less then 10 pulling and up to 11.5.

[6.6]

Originally Posted by elkhornsun

The LML also produces about double the torque of your LBZ engine

Why do people think polluting the air people breath to save a few bucks is a good thing. It is neither ethical or legal if anyone cares about either anymore.

I bet my LBZ produces double the LML TQ, I have a dyno sheet to prove this, and why do you drive a internal combustion vehicle anyway, if you think you are not polluting my air???

[elkhornsun]

GM increased the power output of the engine and not its fuel efficiency. It takes a certain amount of work or fuel to pull a load or take it to a higher elevation and to overcome air drag. The new trucks may get better highway fuel economy when not pulling a load and not being driven at 70 MPH or faster but towing they are not going to work miracles. Want better fuel economy then get a lighter trailer and one with less frontal area and drive slower.

[6.6]

every person I know with a LML including me get crappy mileage. everytime it goes into regren it uses fuel to clean not drive the wheels, but since my entire exhaust is replaced from the turbo outlet back it got better, also the egr is gone

[mike.t]

Originally Posted by 6.6

every person I know with a LML including me get crappy mileage. everytime it goes into regren it uses fuel to clean not drive the wheels, but since my entire exhaust is replaced from the turbo outlet back it got better, also the egr is gone

crappy indeed. I have a 2011 2500 LGH. Gets 12 pulling a 9k trailer and 12 plus a smig no tow.