LBZ Fuel Mileage

[THEFERMANATOR]

Just got done tuning an 06 LLY/LBZ, and he went from getting 18-19 running 65 with his bullydog triple dog to 21.5 now doing the same exact trip except now with an EFILIVE tune I put in it for him. I believe he said stock he was getting about 17-18. Stock tuning in teh LBZ isn't the best for milage IMHO, theres no reason to be holding 5-6 pounds of boost while running 55 with no trailer on a flat road. It does make for a responsive truck, but is hurting the milage.

[gimpyhauler]

Just got done tuning an 06 LLY/LBZ, and he went from getting 18-19 running 65 with his bullydog triple dog to 21.5 now doing the same exact trip except now with an EFILIVE tune I put in it for him. I believe he said stock he was getting about 17-18. Stock tuning in teh LBZ isn't the best for milage IMHO, theres no reason to be holding 5-6 pounds of boost while running 55 with no trailer on a flat road. It does make for a responsive truck, but is hurting the milage.

Sure would like to hear more about that tune. That is an impressive mileage gain for cruising.

[Mark Rinker]

My observations are have been that LBZ and LMM powered trucks get about 15% -20% less MPG than the LB7s when driven unloaded.

When towing, the LMMs do a little better than the LBZs, and only about 5% - 10% less than their LB7 predecessors, with much more stock power and a much greater ability to diffuse heat from the cooling stack. The LMM is a major improvement over the LB7 in the power department for just a little more fuel consumption, and still a measureable improvement over the LBZ family in both MPG and heat management.

After 11 years of production, team Duramax continues to improve...

[THEFERMANATOR]

Sure would like to hear more about that tune. That is an impressive mileage gain for cruising.

This was with an EFILIVE tune that I got from another forum. I tweakd it slightly to smooth it out, but it is a pretty basic tune. About 2-4 degrees more timing in the cruise area, and the boost was lowered about 3-4 pounds at cruise as well as opened up the turbo vanes. It made it a little sluggish to respond to throttle changes, but it was a good trade-off for the milage gains. Plus it was a DSP5 tune so all he had to do was flip the switch on the dash and it came right back to life.

My observations are have been that LBZ and LMM powered trucks get about 15% -20% less MPG than the LB7s when driven unloaded.

When towing, the LMMs do a little better than the LBZs, and only about 5% - 10% less than their LB7 predecessors, with much more stock power and a much greater ability to diffuse heat from the cooling stack. The LMM is a major improvement over the LB7 in the power department for just a little more fuel consumption, and still a measureable improvement over the LBZ family in both MPG and heat management.

After 11 years of production, team Duramax continues to improve...

With a basic tune the LBZ and LMM can both get almost teh same milage as the LB7's, and like you pointed out they are so much more refined and powerful. After tuning and driving one, I kick myself for swapping in a LB7 into my BURB, the LBZ would have been worth the extra effort in the end.

[MadPainter]

hi i have a 2006 with 94000 mi with the lbz and if i keep it uner 1700 rpm on the hwy i get 23.2 mpg's

[BigRabbitMan]

For reasons unrelated to mileage, I am going to be using a Banks tuner in my FMC motorhome conversion to the LBZ (there is a thread in the Conversion forum). The tuner has an "economy" setting.

Does anyone have any experience with using this setting in a Banks tuner. Any thoughts on a percentage improvement in mileage that would be reasonable to expect vs the stock setting. I will be basically running "loaded" all of the time as the coach weighs about 14,500 lbs.

[Scooby]

I am wanting to get the best MPG out of my new to me 2007 2500 CC LBZ with 248k on the clock. I drive MOSTLY unloaded, in Florida, and im only seeing 16 -17 mpg. The tires on the truck are very new 285/75/16 , and I do correct for larger tire size in mileage calculations, and use GPS to compare. Im wondering how much the larger tires effect the fuel mileage, and what difference I would see if I went back to the 245/75/16 size that came on the truck. From what I have found, my tires are 2" taller, so it raises the truck 1 inch. I have always heard lower truck = better mileage, but I dont know how much 1 inch will change things. Any experience / suggestions would be greatly appreciated.
I am also planning to install a DSP5 and EFI tunes at some point. I want the economy tune, and the ability to switch to more power when I need it. I think this would give the best results for better mileage, over messing with the tires.

[spongebob]

21-23 on a stock engine, 420,000 miles on the clock. That’s Highway mileage..

[a5150nut]

Just went from Knoxville TN to Fredericksburg VA round trip 2006 Sierra 3500 Dooley. Hand calculated 15 1/2 up 16 1/2 back. Just a couple suit cases in the back. Dash computer had me at 14 1/2.