what to buy?

[gmchotrod]

looking to buy a GMC duramax, i have heard the emissions regulations on the new diesels have robbed them of a lot of power and moreover made it more difficult to modify them, is this true? i like the new body style but i don't want to have all kinds of problems and spend buco bucks just to get milage and performance out of it.... any thoughts??

[Johnasara]

The new ones are great, If you pull off all the emissions Crap. If you live in an area you have to do testing in your screwed. If you want any kind of a warranty then you cannot modify one. I put the DPF delete kit on two so far and they were relitivley inexpensive. I also have a LBZ that has an exhaust and programmer that did not cost a whole lot. It all depends on how you want to spend your money. There are vendors who have programmer/exhaust packages that range from inexpensive to holy crap!! My LBZ will smoke any one of the other two but I have more money in it.

[gmchotrod]

ok DPF and LBZ, i have seen these acronyms passed around a couple times now, what do they stand for, i'll probably say "duh" when you tell me but i'm drawin a blank

[Johnasara]

DPF is a particulate filter, its part of the emissions on the new LMM engine code duramaxes. They are the new bodystyle. My personal truck is an engine code LBZ basically the same as the new LMM but without all the DPF and emissions stuff on it.

[gmchotrod]

i see, so is a particulate filter the same concept as the catalytic converter or are we talking something totally different?

[Durallymax]

Think of the DPF as a MASSIVE air filter because that is exactly what it is, you are trying to push all of your exhaust through a honey comb that is far from high flowing. In addition before that you are pushing it through the oxidation catalyst which traps the soot first then during regen sends it back to the DPF.

To burn off this soot the engine dumps fuel on the exhaust stroke which is then ignited further down the exhaust stream, this burns the soot from the oxidation catalyst back into teh DPF. This cycle takes a little while and generates immense heat, which was proven by the idoits at ford who didnt set any limits on how much fuel was to be injected thus causing flames out the exhaust.


LMM is the 07.5-present engine code
LBZ is the 06-07 engine code
LLY is the 04.5-05 code and there were a few 06 LLYs that were more similar to the LBZ
LB7 is the 01-04 code

LMK is the new 4.5L duramax.

These are not acryonyms just build codes. We use them to identify the engines bettter as all of the duramaxes dont have many huge differences.

If you live in a state that doesnt do emissions testing and you have a good relationship with your service dept. deleting the DPF is the best choice you will ever make. You will need a DPF delete exhaust and a programmer or EFI Live which gets rid of the Regen cycle and DTCs.

[gmchotrod]

so i see a lot of guys' trucks on here that say something like "4" exhaust turbo back" basically, strip the exhaust off and straight pipe all the way back (maybe a flow master in there somewhere or something to cut down from too much noise???) then re-program the truck.... is it hard to select, purchace and run these programmers??

[gmchotrod]

oh, and the engine code "LMM" for example would be present in the VIN number I am assuming??

[Durallymax]

The 8th VIN number tells the story, here is the breakdown.

01-04: 8th digit "1" LB7
04.5-05: 8th digit "2" LLY
06:8th digit "2" LLY
06-07: 8th digit "D" LBZ
07.5-present: 8th digit "6" LMM

A 4" turbo back exhaust replaces everything with mandrel bent 4" pipe from the downpipe back it does not replace the downpipe.

a Cat back exhaust bolts up to the cat and replaces everything from there back.

Atermarket exhausts are always beeter than strighpiping it and in the end you have close to the smae amount of money tied up. The aftermarket 4" exhausts utilize mandrel bends and eliminate uneccessary bends and crimps in the stock exhaust.