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Discussion Starter #1
I mainly use my 2007 LBZ old body style 2500 to pull my 6000#+ toy hauler.
without the trailer i can get 18-19 on the hwy with the K&N air cleaner and using the gray bottle diesel kleen which i am happy with.
when i load the toy hauler the mileage drops to 8-9 mpg.
i have stock tires and i also hand calculated the mileage and found that the onboard computed mileage is very close to it.
truck only has 71,000 miles on it.
is this normal mileage based on the trailer weight?
i use the tow mode, the truck doesn't seem to be lacking in power, but a little more grunt when passing would be nice.
the fuel filter has less than 2000 miles on it.
I bought this truck used and i love it!
any suggestions will be appreciated
Dave
 

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That is a little low IMO. A turbo back (downpipe back) exhaust and programmer would help some. When towing, how fast do you drive and do you allow it to shift into 6th or lock it into 5th? Some guys say they get better mileage towing in 5th gear....that would help your "grunt" too I would think.
 

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Discussion Starter #3
I pretty much let the trans"do it's thing. i probably should manual shift to 5 and leave it there.
most places are pretty flat around here.
i usually travel around 70 maybe 75 if it's really flat.
tried backing down to 65 with no change.
 

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Discussion Starter #4
what would a normal mileage be for stock, and how much improvement could i expect from mods x mileage?
 

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I have an '06 LBZ and recently towed 6,000 pounds about 500 miles, all on uphill/downhill terrain. I averaged about 15 mpg. The 8-9 definitely seems too low.

BTW, my truck is completely stock at the moment as well.
 

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what would a normal mileage be for stock, and how much improvement could i expect from mods x mileage?
I have an 06' CC LBZ 4x4 and I get about 19-20hwy and 14-15mpg towing my 6000# boat/trailer and it was completely stock. I just recently installed a 4" MBRP Turbo back and a PPE Standard on level 2 and getting about 22hwy. I won't know if any difference towing until the summer time but so far I'm quite happy with the mods.
 

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Discussion Starter #7
next question....
seeing that others have 14-15 mpg towing the same load...what could be the problem?
is the type of FF important?

i bought this truck used with 68,000 on it.
can't tell if it had a programmer on it, if it was taken off without resetting back to normal would that screw up things.
 

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next question....
seeing that others have 14-15 mpg towing the same load...what could be the problem?
is the type of FF important?

i bought this truck used with 68,000 on it.
can't tell if it had a programmer on it, if it was taken off without resetting back to normal would that screw up things.
I just been using the Ac Delco FF. Not 100% sure what the problem would be. Is your toy hauler an enclosed trailer? Pulling a box through the air vs. a streamlined boat might get ya different fuel mileage but probably not as low as you are seeing. Hopefully someone with more experience will chime in.
 

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Is your toy hauler a bumper pull? If it is you might want to think about upgrading to a 5th wheel.
 

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Bikes,

I pulled my 39 ft 5er back and forth from home over Christmas and it is around 15k. Going home I got 10.5 mpg, I haven't filled up since I got back. I had used nearly half a tank and I filled up immediately after unhooking and I passed the station and showed by hand 10.5 mpg.

This is normal regardless of what I have done to the truck, new filters vs some life on the filters, et cetera.

I was in tow/haul the entire time and drove 65-70 mph. I actually think mine can do better than this.

There are many, many factors though: terrain, oil lubrication ability, speed, acceleration, and on and on.

I would say though with 6K you should have no problem running 70-75 mph and still get 12+ mpg.

I will try and get SETexan to chime in here too. He pulled a trailer similar to mine before and after the exhaust mod and may be able to shed some more light.
 

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I have an '07 Silverado Classic that is bone stock and when I tow it is a 28' Airstream TT that weighs about 7k loaded. Unloaded highway mileage at 65 mph is from 19 to 20 mpg (hand calc'ed and filled to the rim each tack), I use stanadyne performance formula every tank. Towing at 65 mph will usually see 13 to 14 mpg. If I slow down to 60 mph I will be in the 15mpg range and 55mph will put me in the 16 mpg range. Going up to 70 mph kills the mileage, down to the 11.5 range, even with a relatively aerodynamic TT.

Drag increases at a rate of the square of velocity, so if you are trying to tow a big square box, your speed will be the biggest killer of your mileage.
 

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All hand calc'd with GPS

Edge J/A with Power Service(Grey Bottle) 15.5-16

Stock with Amzoil DC and Cetane Boost 18

In the Edge J/A defense, I think there was something wrong with it. Truck really started running wierd prior to going stock.
 

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Very few mods on my LLY....stock tune, but I do have the LBZ MP, EGR Block, TCAI with a Kitty that is gone. Cruising on the freeway at 65 mph I average 24 mpg (Hand Calculated). Towing my boat (6500 lbs) I've been getting at least 13 mpg if I keep the speed around 60 mph. I have converted to Amsoil, and using Opti-Lube XPD fuel treatment/cetane booster.
 

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It might be your toy hauler. Those toys are pretty tall. Lots of head wind. When i haul 20' containers on my gooseneck i get about 8-9 mpg. I live in Houston and we get alot of southern winds. That might have something to do with. I've hauled about 24,000 lbs on my trailer and got 12-14 mpg. Wind drag is a common thing for loosing MPG. It's not the weight so much it's how tall is it and what kind of winds you have. Hope this helps.:drink
 

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Wind drag is the most important thing. Is like hanging on to a sheet of plywood in the wind or a 2X4 in the wind. The toy hauler is like a sheet of plywood just like my travel trailor.
some guys put up a air deflector on the roof of the truck to deflect the wind up and over like some in the Big Rigs. Even they have gone arodynamic in the past few years.
 

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Not sure what my actual mileage was but the DIC showed 10.5-11mpg running the Banks 6 Gun. Took the load across the scales and total was 25,700lbs. Tall 5th wheel and pretty heavy. Running 60-65 mph from Elko, NV to Pocatello, ID. Not huge mountains but hilly and hi-desert. Seemed to run ok but now I wanna try the LBZ or Kodiac mp.
 

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I get 7-9 pulling my 3910 cyclone at 70-75mph. I get 10-12 around the farm and probially 15 if im lucky on a road trip empty. I'm looking to inprove my mpgs as well. ?????
 

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hmm i get 12-13mpg with a 26ft enclose double axle trailer with a 86 monte ss shit load of tools welders and torches roll away box packed with toold air compressor jacks stand ect...and my truck still hauls ass thats hand calculated with 20"s and 33's up hills mostly also
 

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I get 7-9 pulling my 3910 cyclone at 70-75mph. I get 10-12 around the farm and probially 15 if im lucky on a road trip empty. I'm looking to inprove my mpgs as well. ?????

Couple of things that could be hurting your fuel economy: winter blend fuel & conditions, not very many miles on your truck, and maybe your speed. Towing at 75 mph will not help your mpg.

Are you using a fuel additive? Are you idling alot. Is your truck garaged or does it sit out? A cold soaked truck in SD will take a lot of miles to warm up the tranny, motor, and diff. Warmer temps with a broken in truck will get you better mpg.
 
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