I messed up by trading a 2006 for a 2008. The 2006 had incredible power and got great fuel mileage. The 2008 has low power and gets about 14 mpg driven slow (average about 50 mph). Also, I live too close to work and it does not have time to regenerate the DPF. I have to make a special trip just to regenerate and waste all the extra fuel. I live in the USA so I cannot modify the exhaust system much. I guess I must either trade back to a 2006 or get the 2011 that has a different emission system. I spoke with the local Chevy dealer and he said all new diesels sold in the USA will require the DEF system.

Sorry to hear about your mileage. I didn't get that great of mileage at first; 12.5 around town and 18 on the freeway (going 70). I now have 25k and my mileage is much better. I haven't checked it in town lately but towing 8k and with 1k in bed I got 11.6 pulling over the Sierra Mountains. On the freeway I am getting 21 going 60 and 19 going 75. Give it some time and it will improve.

I also live close to work 1.5 miles and drive it every day. When it goes into regan it can take two days to complete.

Thanks for your reply. I have 42K miles. I drive in city traffic mostly so maybe I'm getting normal fuel mileage. I take off really slow trying to get better mileage, but it probably won't have in town. Maybe I will get better mileage on a road trip.

2011 still have DPFs. They added additional emission equipment using the diesel ehaust fluid.

Brian

2011 Dodge Cummins doesn't have the SCR (Urea) System. Stop listening to salesmen. :)

I just bought an 08, but haven't taken possession yet. I knew going in they were not the greatest on fuel, but I got it to be put to work.

I messed up by trading a 2006 for a 2008. The 2006 had incredible power and got great fuel mileage. The 2008 has low power and gets about 14 mpg driven slow (average about 50 mph). Also, I live too close to work and it does not have time to regenerate the DPF. I have to make a special trip just to regenerate and waste all the extra fuel. I live in the USA so I cannot modify the exhaust system much. I guess I must either trade back to a 2006 or get the 2011 that has a different emission system. I spoke with the local Chevy dealer and he said all new diesels sold in the USA will require the DEF system.
where do you live? Does your state do emissions testing on diesels? You could always replace your exhaust and keep your DPF just in case...

I'd do a DPF delete myself. Where I am at, dealerships sell new trucks with DPF deletes.

where do you live? Does your state do emissions testing on diesels? You could always replace your exhaust and keep your DPF just in case...

I'd do a DPF delete myself. Where I am at, dealerships sell new trucks with DPF deletes.

Thanks for the reply and suggestions! I live near San Antonio, Texas. My truck is registered in Mississippi because it was bought by my brother's small business and I make the payments. However, I might get the title put in my name so I can register it in Texas. Plates are cheaper here. I live in Medina county and Hondo or Castroville is where I would register the vehicle. It requires an inspection, but I don't know if they look under the truck or hood for anything. I would like to install a new exhaust system or at least delete the DPF and catalytic converter (if it has one). I would like to have a muffler so it is not too loud. There are so many programmers, I have no idea which one to purchase. Also it came with an Airaid air filter system and it seems to cause the MAS problems. I cleaned filter and lightly coated it with oil. I've read on this forum that the original ACdelco is the best filter. Good news that the dealerships around here will delete those DPF. Seems our environment protection agency is out of control.

Since you are in Texas, you don't have to worry about deleting the DPF. Problem solved... :D

For a programmer, I'd get a Quadzilla if you just want to delete the DPF and not add power, or a PPE unit if you want to add power.

The lesser quality filters do cause MAF sensor problems as the LMM is sensitive. I'd go with an S&B filter IMO, or get a stock one.

Thanks for your help!

DPF delete is a great option for "off-road" racing trucks. Mileage and power is greatly improved.

Thanks for your reply. I have 42K miles. I drive in city traffic mostly so maybe I'm getting normal fuel mileage. I take off really slow trying to get better mileage, but it probably won't have in town. Maybe I will get better mileage on a road trip.

The city/in-town driving sucks...while I can squeeze 22 mpg on the freeway unloaded, my in-town driving yields around 14-15 mpg. Speaking to some of my buddies who own LMMs and do mostly city driving, my mileage is on par with theirs.

The city/in-town driving sucks...while I can squeeze 22 mpg on the freeway unloaded, my in-town driving yields around 14-15 mpg. Speaking to some of my buddies who own LMMs and do mostly city driving, my mileage is on par with theirs.


x2. Chris

Thanks for the feedback, everyone! My truck is in that range or just a little lower. I need to upgrade the exhaust system, install an EGR blocker plate, and get a programmer/tuner. I also want to get away from the oiled air filter since it takes me time to clean and oil, and then wonder if I have too much or not enough oil on the filter. Using the OEM takes the guessing out. Also, I'm getting the code for the MAS problem.

Its from the oil on the Airraid. I'd get a dry filter, either aftermarket, or stock and do the PPE airbox mod.

my 09 gets terrible mileage. I did the complete exhaust(dpf/cats delete) with a edge tuner. My truck gets maybe 1 mpg better. Which it now gets about 14 mpg daily drving. My 06 would only get 12mpg. I drive 20 miles to work, one red light, all level ground.

That is some discouraging news. What about power increase with the modifications? I'm getting about 13 to 14 now driving less than 60mph, but I have several red lights. I'm stock now except for the air filter. I will keep my expectations low so that spending the money on mods does not disappoint me much. I had an 06 2 wheel drive that was stock (I think) and it got about 18 to 19 driving back and forth to work. I bought it used and it belonged to a car racing guy that used this truck to pull his cars to the tracks, so maybe he did something to it. My favorite older car was my 1969 Camaro - great body style. Cheers

That is some discouraging news. What about power increase with the modifications? I'm getting about 13 to 14 now driving less than 60mph, but I have several red lights. I'm stock now except for the air filter. I will keep my expectations low so that spending the money on mods does not disappoint me much. I had an 06 2 wheel drive that was stock (I think) and it got about 18 to 19 driving back and forth to work. I bought it used and it belonged to a car racing guy that used this truck to pull his cars to the tracks, so maybe he did something to it. My favorite older car was my 1969 Camaro - great body style. Cheers
Our LB7 gets 20 mpg unloaded... Your LMM is just the exception and something is up... Some trucks are just different though. Maybe yours was built at 4:45 on Friday.

I did a 4" MBRP exhaust and EFI Live on my 08. We have emissions testing here now every two years. The exhaust is really easy to take off and re-install the OEM DPF stuff for the test. I am running 33.25" tires, leveled and my last trip was about a 2.5 mpg improvement getting 19.2 mpg doing 75 mph with four adults and a full bed. I'm interested to see what it will get tonight, I'm driving the same 270 miles but this time my DSP5 switch works and my tune won't be stuck on "stock/DPF delete" tune. :mad: I will try the 50hp or 80 hp tune to see if i can improve on the mileage.

If you don't want a loud exhaust, look into the Corsa which is supposed to be the quietest or the Diamond Eye. I have the MBRP and although it fits perfect it was just a little loud for my liking, mainly the drone. Finally I bought a Corsa muffler and removed the MBRP muffler and it almost sounds stock, much better for me. I had the loud exhaust on my 6.0 Ford and I'm done with the noise.

Good luck.

I don't want a loud exhaust. I'm glad I read your response before making a purchase. 19.2 mpg is excellent.

Thanks!

19.2 is great for me since the best I could get with my lemon lawed 6.0 Excursion with 37's was just under 17! I'm really happy with this truck.

I just drove four hours to our river place in Arizona and it was really quiet in my cab all the way here!

Here is the difference in the two mufflers

http://www.pbase.com/leros/image/126794670.jpg

Where did you get the Corsa muffler? I've been thinking on getting the 4" MBRP exhaust, EFI Live, and DSP5 switch. My brother has a 2005 Duramax and has been putting off getting a newer truck because of the emissions control. I think 2007.5 to 2010 are good and since he lives in a state with no emissions testing, he can do the modification and not have to reverse them. Thanks for the picture. I sure want the quieter muffler.

I bought the MBRP system off of this site in the FS section for $200 from a guy selling his truck. I got the Corsa from Chad at Alligator Performance but Corsa does sell a complete 4" system for these trucks. The Corsa stuff is pricey but damn good quality. Call Chad, he will set you up, tell him SteveO sent you ;))

19.2 is right where I'm at with the +70 or +90 tune / no-DPF, 75. 12-13 towing my 9000 lb boat/trailer at 70 on the +50 (towing) tune.

There are several tuners, several exhausts. Most of us have put alot of info into one thread to keep it all in one place:

DPF_/_Non-DPF_thread (http://www.dieselplace.com/forum/showthread.php?t=212196)

Thanks. I've read the DPF / Non-DPF thread. I probably over analyze everything since I'm a burned-out engineer. Also, I want to stay as close to stock as I can related to suspension, wheels, and tires. I think a 4 inch SS Turbo back with a quieter type muffler will work for me. From what little I know about the EFI live, I'm leaning that way. It probably allows more options than I need, but I think flexibility may be good for the future. Everyone here has been very helpful and I greatly appreciate it! I'm open to all suggestions, recommendations, links, threads, etc. I'm fairly new with diesel power.

my 09 gets terrible mileage. I did the complete exhaust(dpf/cats delete) with a edge tuner. My truck gets maybe 1 mpg better. Which it now gets about 14 mpg daily drving. My 06 would only get 12mpg. I drive 20 miles to work, one red light, all level ground.

Your Tuning Maybe? My 09 is EFI'd and the rest of the items in my Signature.

No DPF no DOC, just 4 inch straight back, sounds great, smells great, mileage great (for an LMM)

17.5 mpg towing

Funny though, unloaded is not dramatically better, likely because I can't keep my foot out of it!

Since you are in Texas, you don't have to worry about deleting the DPF. Problem solved... :D

For a programmer, I'd get a Quadzilla if you just want to delete the DPF and not add power, or a PPE unit if you want to add power.

The lesser quality filters do cause MAF sensor problems as the LMM is sensitive. I'd go with an S&B filter IMO, or get a stock one.


Does deleting the DPF not void your warranty??? I called my local GM dealer and they were telling me that deleting the DPF would void warranty so I threw that idea out the window..

Does deleting the DPF not void your warranty??? I called my local GM dealer and they were telling me that deleting the DPF would void warranty so I threw that idea out the window..
It CAN, but not necessarily. I have been back to the dealer twice, and everything - including the faulty ECM that had been tuned for DPF delete - was covered.

My service manager said he had no problem with the truck in it's current form. The only time his hands would be tied is if there was evidence of a wild tune (burn patterns on the pistons) and/or evidence of anything other than diesel being sprayed into the engine (Nitrous, propane, etc). All of the guys that worked on the truck were happy with the mods and even REMINDED me to upload a tune before I left to turn off the engine light!

The trick is to go talk to the service manager. Tell him what is done to the truck BEFORE it goes in. I told him I would be happy to put it back to stock before it came in - if he didn't want it on his lot with DPF-delete. He said he had no problem with it.

Yea, my only issue is that I have been told one thing, get there to discover a whole new thing.. i.e. "hey its cool with the dpf delete" then an hour later a phone call that says " hey we arent going to be able to cover it because it has had modifications that voided warranty" lol I would be PISSED! I want to delete that POS DPF BAAAD.. but possibly voiding warranty obviously has kept me at bay on that idea.. If I knew that it was cool I would do it in a heart beat!

If you are driving city traffic and constantly jumping on the brakes, idling at stop lights and signs, then gunning it back up to speed to keep from being run over, there is no way you are going to get better than 12mpg unloaded - ain't gonna happen with a 6.6 liter engine unless you can change the laws of physics... Those claiming that they are getting 19 in city driving are delusional, or their 'city' has one stop light...

My 08 LMM is as it came from the factory ...
In mostly city driving I get mostly 12 - and sometimes as high as 14 depending on the percentage of open road versus streets and if I am timing the lights perfectly...
In running to the marina 32 miles, with a mix of rural roads, 12 miles of expressway and 5 miles of city streets I range from 18.5 to 19.2 unloaded (and depending on how I make the red lights)
In running the exact same trip loaded with my Ranger Tug (11,000 pounds with a big set of pilot house windows pushing air) I average in the mid 12's every time... When I pulled the boat from Virginia to Michigan I averaged 12.2 for the entire trip including mountains and I was not babying it...

If you are getting 8 in the city you may have a vehicle problem (unless this is NYC then 8 is great!) - work with the dealer...
It is likely (not guaranteed) that I can get in your truck and jump the mileage 1 mpg or more because of how I drive - mild throttle for acceleration just until it reaches a shift point then back off slightly on the throttle so it will upshift promptly... This is so automatic I don't even think about it...

denny-o

For comparison, with the mods listed on my LMM, I average (50/50 city and highway) 19.5MPG hand calculated. If I reset the DIC and do a straight state highway run at 60MPH, I see as high as 26MPG. On an interstate run at 73-74MPH, I will see 20-21MPG.

My mileage improved 25% when I removed the DPF and EGR.

Excessive ambient temp (95+) and winter blend fuels will hurt your mileage.

Everyone's circumstance is different, not suggesting modding and voiding your warranty is a solution for you, just providing the data for consideration.

If you are driving city traffic and constantly jumping on the brakes, idling at stop lights and signs, then gunning it back up to speed to keep from being run over, there is no way you are going to get better than 12mpg unloaded - ain't gonna happen with a 6.6 liter engine unless you can change the laws of physics... Those claiming that they are getting 19 in city driving are delusional, or their 'city' has one stop light...

My 08 LMM is as it came from the factory ...
In mostly city driving I get mostly 12 - and sometimes as high as 14 depending on the percentage of open road versus streets and if I am timing the lights perfectly...
In running to the marina 32 miles, with a mix of rural roads, 12 miles of expressway and 5 miles of city streets I range from 18.5 to 19.2 unloaded (and depending on how I make the red lights)
In running the exact same trip loaded with my Ranger Tug (11,000 pounds with a big set of pilot house windows pushing air) I average in the mid 12's every time... When I pulled the boat from Virginia to Michigan I averaged 12.2 for the entire trip including mountains and I was not babying it...

If you are getting 8 in the city you may have a vehicle problem (unless this is NYC then 8 is great!) - work with the dealer...
It is likely (not guaranteed) that I can get in your truck and jump the mileage 1 mpg or more because of how I drive - mild throttle for acceleration just until it reaches a shift point then back off slightly on the throttle so it will upshift promptly... This is so automatic I don't even think about it...

denny-oyours sounds like mine . I now have 49500 miles on her.total stock. regular E rated tires not over sized.I average around 15 miles to the gallon between some hwy and city driving.on the hwy not towing I get about 19.5 to 20.5 down here in florida.When pulling my 18 foot lund pro-v I get about 13.5 to 14.0 and pulling my 22 foot funfinder-x I get about 12.5 to 13.5. overal not to bad with a 4x4 truck of this size.I have been looking at the pdf delet. When I added up the cost of doing it,I came in at around $1000.00. At that cost it would take a long time to get that money back seeing you may or may not get much more than a mile or 2 per gallon gain. For now I will stay stock.

No load, I get 11-12ish city, 19.x Hwy

Towing my 14+K 5'er @ 62MPH, I get 8.x-10.x, depending on wind, state, etc..

17,xxx on the ODO, completely stock. I'm thrilled when I get over 10MPG while towing that monster :D.