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‘08 LMM mods

3K views 15 replies 10 participants last post by  WOLFN8TR 
#1 ·
Hello, this is my first time posting. About to get my first truck so bear with me if I seem clueless. I’m getting an ‘08 gmc 2500 with around 200k miles. I’m gettin a great deal on it, buying it from my grandparents (who bought it new in ‘08) for 5k. Basically, I’m 16 with no real job and I need to get the best mpg I can and make the engine last as long as it can. It will be a daily for my 40 mile round trip to school. From what I’ve learned the main things I should do is a EGR delete (do I need a finger stick in the lmm, or is there a different way to do it?), a PCV reroute, a DPF delete, and then get a good tune. I’d like to do everything myself, besides maybe the tune. What are yalls thoughts? Best way to go about all this? I have decent mechanical experience, dirt bikes and a vw, but I haven’t really done anything like this. Any help is appreciated
 
#2 ·
You need to understand that what you want to do and what you should do are two different things. EGR delete, DPF delete both require programming that you need BEFORE you start removing things and that the EPA is heavily fining people who provide such programming. You are not likely to find such programming in the USA.

My suggestion is to keep up the maintenance and drive the truck. Keep your $$ in your pocket.
 
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#4 ·
Ok, well I guess I didn’t really understand the complexity of the whole situation. I want the truck super bad and I’m getting a deal, but it won’t be financially beneficial compared to buying a small 4 banger truck. Just wanted to see if there’s anything I could do that would make it superior to my other option for a vehicle. Are emission standards really that tight? Seems a little ridiculous and overkill. I’ve heard that the EGR causes a lot of carbon build up in the intake and reduces engine life, and that you shouldn’t do an EGR delete without a pcv reroute. Even an EGR blocker plate would require an illegal tune?
 
#5 ·
To me, the LMM is about as good as it gets. I had an '09 LMM and it would get around 21-22 on the highway running 70-73 (about 1800 - 1900 rpms and no load). Got between 14 - 16 in town driving. If you buy this truck and keep the rpm's under 2K on the highway you should get fairly decent mileage. Once you crack that 2K rpm, mpg falls like a rock. At least mine did. Best thing is no def to deal with. Funny thing, my buddy had an '08 and he never got more than 18 mpg in his. Basically the same exact truck as mine. We could never figure out why.

If you buy it and have to do something to it, search the web for Diesel Domination and check out their tuners, specifically for the '03-'10 Duramax. No deletions, only makes the motor run more efficiently. My mpg went up an average of 15% with the 80 hp tune. Did it give me 80 hp? Who knows. I doubt it, but it was much livlier. Good luck to you if you buy it.
 
#6 ·
As others have already pointed out there is no such thing as saving money with a diesel truck. Unless you really NEED a diesel truck for towing and such, there are much cheaper options out there.

My LMM has been the best vehicle that I have ever owned, without a doubt. Now 12 years old and the only things that have failed in 12 years are; TCM, one glow plug and the fuel filter head.

My fuel mileage has not been the same as @shunter but I have a dually. My in town mileage is about 13, highway mileage 18, towing a 15k 5vr 10 MPG.

My truck is bone stock beyond the tires and wheels. Left unmolested these trucks can offer many miles and years of trouble free service but again proper maintenance and upkeep ain't cheap.
 
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#8 · (Edited)
Another vote for just keep it stock. Not having to deal with DEF but still being emissions compliant is awesome. I loved my LMM.

And to answer your question, yes, to stop the EGR or DPF from functioning in any way requires a tune to be put on the truck. You won't find much availability of parts to get that done anymore, and we can't even discuss it on the forums anymore because the EPA is using the forums to help build cases against companies providing products and services that allow tampering with emissions controls.

It sounds like you have a good opportunity on a good truck. If the body isn't rusting, that truck will last you a while. Just drive it and love it. Spend that tuning money on some wheels and tires for it.
 
#10 ·
The body definitely isn’t rusting, it’s been babied by my grandparents it’s whole life, they rarely hit 70 when they’re driving it. BosieRob, run it like a rotary basically? Would accelerating quickly every now and then be healthy for it? I’m glad y’all are saying to keep it stock, I was ready to put a lot of work into it
 
#9 ·
I would recommend getting an idash, since you can initiate parked regens. Due to you only having a 20 mile trip to and from school you will not be able to get a full regen in, from my understanding. You can also monitor a boat load of stuff with it.
 
#11 ·
Duramax like long hard runs, preferably towing a load.

Accelerating quickly only hurts the drive train IMHO.
 
#16 ·
LoL What are you talking about?
Lift Pump? Intake? Exhaust? Nope...
 
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