LB7: Better mileage?

Guns and Grease

New member
Apr 12, 2011
11
0
0
Northern WI.
Today I drove to pick up an RV on the way I got 18 mpg and on the way back with 7000# RV I got 11 mpg. Being new to the diesel, is that about what to expect or can I do better?
It is stock with a 4" pipe from the turbo. Ideas?
 

JMDuramaxLB7

YOU SAID MEMBER!!!
Jun 3, 2007
744
0
0
Missouri
I got around 10 the last time i towed are 2 tractors on my 25 ft gooseneck. I was running a 80 hp. tow tune at the time. The truck will usually get around 20 to 22 empty on the same tune.
 

s3gulit

Teh Farmer
Dec 6, 2008
173
0
0
Illinois
my efi tow tune i'd get 12-13 on my lb7 towing 30K, all highway 55-60mph. Gotta remember IL is as flat as a pancake though. Truck was a ZF6, with all of the bolt-ons.


My LBZ is stock still, and im lucky to get 14mpg empty...not sure whats up with that, i know a dually hurts a little bit didn't think it'd be that much.
 

Muff

Just Learning
Oct 7, 2013
1,063
0
36
Butler, Pa
Get an Edge programmer and a FASS fuel system. That should give you at least 3 to 5 more mpg's.

He has to be joking.

Pulling the bike trailer (enclosed 16 ft box trailer) with 2 dirtbikes and some gear I got right handy to 11mpg bone stock. Those enclosed trailers are like pulling a freaking parachute behind you.
 

jevanb

New member
Feb 28, 2011
159
0
0
montrose, michigan
pulling our last TT I only saw 9-10mpg and it weighed in at 7800k , the current 5er weights 12.8k and I see 12.5mpg with no extra mods done to the truck.. areo is everything, and TT campers are not..
 

WI Huck

Where does the time go?
Feb 8, 2012
137
0
16
The engine has the most torque under 2000 RPM and that is where the mileage is the best. Above 2000 RPM mileage drops. Running empty the engine has enough power to do the job. When loaded you will notice the transmission downshifting more due to lack of power. Downshifting causes the RPM to go over 2000 and less mileage is the result. Adding power / torque will allow the engine to stay in the ideal RPM zone. The limiting factor to how much power you can safely use is EGT's. Added power creates higher exhaust gas temps. Any of the generic over the counter power adders like Edge, Bully Dog, etc. will improve mileage in loaded situations. EFI will also in the hands of a competent tuner. EFI shines in trucks where the engine is modified because the over the counter tuners were designed for stock setups with possibly an intake and exhaust.
 

hotdogstand

Member
May 27, 2013
35
0
6
Norfolk, VA
I used to get 21 highway empty with my ATS E-power, even with 33s. Keep it under 70 mph, and like Huck said, 2000 rpm is the sweet spot, any higher and your mileage will suffer.
 

Bersaglieri

New member
Dec 28, 2013
82
0
0
I got 19.7mpg on a tank of 30% city, 70% highway. Muffler delete, K&N replacement filter and Idaho Rob economy tune. This was driving 75-77mph on the highway miles with 265/75/16 E range Goodyears. I haven't towed an entire tank in one shot, but when I tow a 24ft goosneck @ 75-77mph the mileage definitely suffers lol.
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
3,890
43
48
43
ZEPHYRHILLS, FL
Your milage sounds about right. I do a touch better with mine, but i have 3.42 gears in mine with narrow stock tires. And don't believe teh hype when somebody tells you you can do this tune or box and see 3-5MPG better. The lie o meter may read higher, but your actual milage won't go up that much. I've played with tuning ALOT, and have yet to find any magic combo that makes the milage jump way up. Drive it easy, and keep the RPM's down is about all you can do. When I'm trying for milage I will actually let off the throttle to let it shift then give it throttle again until I want it to shift again, then I let out and repeat. I try to keep my RPM's under 1800 at all times, even driving around town. The newer trucks with a VGT can see pretty big milage jumps from tuning since you can open the turbo veins up and reduce the load on the engine, but the LB7 was about as good as it could be in stock form.