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Discussion Starter #1
2008 LMM with 98000 miles and I have had enough of the lost MPG and inconveniences of the regens. Especially when I roll off the highway in town and start making short trips right when the regen starts. What a waste of fuel and the oil life just starts dropping. Then I wonder if the DPF is someday just going to be beyond cleaning what a regen will do. Also, the issue of the LMM method using the same injectors that fuel the cylinders, being used to burn the DPF, all that fuel washing into the oil probably.

I need something simple, reliable, and economical. I have of course read on forums about many tuners being the best. Such as EFI Live, PPEI, Autocal, EZ Link, etc. I want to just do the work, myself, set it, forget it and drive it. I don’t need to worry or want to make adjustments along the way. I also, have to consider the costs to get it by my “accounting” department at home! It probably will have to be in the $600-800 range.

One solution that I see little reference to is the GearBoxZ tuner. I know it is quite simple and has the option of just turning off the DPF and EGR and also one that has one +70 hp tune as an option also. Which, if it gives better economy I would use that. The truck has always had plenty of power for towing. We had a fifth wheel, about 8000 lbs. and never lacked for power to pull through any mountains or maintain speed. MPG were definitely speed and wind affected, anywhere from 9.5 to 12 mpg, while towing. I am a pretty conservative driver when towing and rarely go over 65 mph if it is a heavy trailer

The GBZ-GMED40-182 is one complete kit I found that seems to address all these areas. Just the tuner and DPF delete pipe. . I probably will add the EGR blocker plate when I do the install.
I don’t want to remove the DOC/CAT or the muffler. Noise abatement is also important.

Does anyone here have any long term use of this tuner or know any documented issues and concerns about the programming working correctly on the LMM?

Since, we will soon be getting another RV we plan on keeping this truck as long as we can take care of it and it stays reliable.

Thanks Guys, I know the DPF thing gets beat to death on here and the correct solution is just as important and sometimes different for each of us.
almost as bad as an oil thread.
 

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See my PM.
 

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Following. in the same situation have a 2008 worktruck id like to delete
 

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Discussion Starter #5
Well, I got the Flo-Pro test pipe with no bungs and the GearBoxZ 4.0
Install went pretty easy.
I soaked all the flange bolts, pressure pipe, and EGT sensor connections for a few hours before attempting to remove. I unplugged the sensors and removed those after I got the DPF out from under truck. It gave more room to work as I was concerned about damaging the sensors or stripping nuts.
I should have ordered the exhaust flange gaskets before starting. One broke, and it was one not in stock. I put high temp red RTV on the gasket to "glue" it together and so far it is fine. I did get a new one, but have not installed yet.
that was the rear, three hole gasket. It would be easy to put in if needed.
I used a small vacuum hose and made a loop to the two rubber hoses after removing the steel pipes for the pressure sensors.
I used a 6" piece of 3/4" PVC with a cap glued on end. I put the sensors in them and sealed the top with tape and RTV. I painted them black and ziptied them along the frame rails.
I put the battery charger on 10 amps to make sure the voltage would be high before plugging the programmer into the OBD port. It was a little strange and kinda hard to understand the tiny womans voice asking questions and prompts on the tiny device. but it all went good and i put in the economy tune.
the truck fired right up. the exhaust sound is not much different, you can tell it is flowing out a lot easier. I left the DOC and muffler on.
I have not yet put in the blocker plate for EGR.
The truck has noticeable power gains when you give it a little pedal action. I have not done any max power runs. Only the slightest haze of grey smoke with heavy throttle.
So far, I am happy with this solution to get rid of the dreaded regens. What an irritation that was. I know it is not much proof yet, but on a 200 mile trip to a drill rig site and home it netted 21 mpg on the DIC. the wind was really blowing that day also.
I am hoping this is my 'new' truck for the next 100,000 miles!
This is just my experience so far. Not saying it is the best solution, but I just want to drive the truck and not fool with any changes or settings.
 

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Glad it worked out for you!
 

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Any follow-up on this topic? I am in almost the exact same situation: 2008 2500 GMC at 100k with terrible mileage and oil life. Looking for improved mpg - don't need a monster tune with big HP/torque. Need a stainless exhaust due to living in NW PA with lots of snow and salt in the winter.

GearBoxZ is intriguin but I'm also willing to pay a little more for an Autocal but I don't need 5 different tunes.
 

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Discussion Starter #8
sevenandeights
I am pleased with the system I installed. It is not perfect, but the solution stopped the regens, increased power, and fuel mileage a little.
The good:
  1. no more regens
  2. more power than a 3/4 ton truck would ever need
  3. cleaner oil
  4. better fuel mileage
the not so good:
  1. the tune threw off the odometer and speedometer. I think the default economy tune must be for 17 inch rims. it might save a speeding ticket!
  2. throttle response is almost too good. the worry is my wife or someone else might lose traction on a wet road
the DIC lies a little bit now, but it makes you feel good. actual increase was probably not more than 1 1/2 to 2 mpg at the best, with conservative driving and unloaded.
Towing mileage increased a little. I towed a 5500 pound RV to New England and got about 12-13 mpg. Again, somewhat conservative driving.
the oil stays cleaner. No block plate installed yet(but i have one), the tune turns it off.
the exhaust pipe has not rusted, but I don't live in Ohio.
it has been about 14 months and 13000 miles since i put it on.
 

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The tune didn’t affect the odo, the tuner needed to know what tires you have so he could recalibrate the speedo.
I don’t know about the gear box 2 but it might/should have the capabilities to enter the tire size for correcting speedo.
FYI, tire height listed for your tires will not be the true height.
Example, mine are listed as 32.76, true measurement 2 different ways they measure 32.20 which will throw off the speedo a little.
 

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Thanks for the feedback. I'd rather spend a few hundred more and get 4 mpg increase. Any thoughts on how to achieve that?

I'm at 13-14 mpg in town with a really light right foot.
 

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FYI disappointing info given to you if you really think you’ll get a 4 mpg increase.
Sorry but that’s a fantasy that will never come true.
No tuner in this universe can offer you what your hoping for.
Please don’t get caught up on these bs claims.

My best mileage was when I first deleted, deleted only the stock muffler and dpf.
Using Quadzilla Stealth II set on economy tune, about 14.5-15 city with a little highway.
Stock was 14.5-15, go figure.:confuzeld
The more I opened up my exhaust my mileage dropped.
Now 13.0 if I baby it same driving.

I just recently did my first solo trip in 12 years that I’ve owned my truck, all trips I made was towing 13,500 lbs.
315 miles round trip picking up a new aluminum jetski trailer, pretty much all highway, running about 70 mph, 17 mpg no hills flat all the way up and back..:thumb:
 

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That's good to know also. I'll stop looking if what I'm after isn't possible. My truck runs fine and I don't have any issues with regens other than wasting gas. I just want to improve mpg.
 

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Start off slow deleting a little at a time.

Start off by deleting the restrictive stock muffler and DPF, get a mild delete tune and call it a day.
With a delete tune your able to delete anything else overtime your heart desires, no tuning changes needed.
Like if you want to block/delete the EGR later on, the delete tune you would
have will not need any changes.

Just make sure you have the correct tire size for the tuner to adjust the speedo.
I pretty much did mine one, well 2 at first muffler and DPF.
So many just jump into it changing everything they can think of, not knowing what really helped.

Just spending mucho bucks most parts really didn’t do anything other than having bragging rights.
I found this out the hard costly way believing all these fantastic magical gains.
The only magic about most of the stuff I did after the beginning was my bank account mysteriously went lower.
 
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