EGR info needed

[moss6]

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I've got an 06' LBZ and am looking at exhaust mods for mpg/reduced heat/added power; in that order of importance. Also do not want any extra exhaust noise if possible. From what I've been reading an EGR blocker may be needed to address the possible code setting issues. That doesn't sound good! This also leads me on a quest to get full understanding of the EGR system and all the effects-disadvantages-advantages of disarming the system. Any help from someone who has a complete understanding would be greatly appreciated.
Thanks

[Kennedy]

Here is a brief overview:

http://www.kennedydiesel.com/docs/Duramax_LLY_LBZ_Emissions.htm


IMHO, a cat back system is a waste of money. A full system will produce fair gains in performance, but nothing stellar. The 06 trucks are pretty darn quiet regardless of exhaust system.

[moss6]

So the EGR is valved and is opened/closed by the ECM? I assume the blocker plate would need to be removed if you take the truck in for any powertrain service.

[Duramaster]

HA HA HA HA............... Thispost reminded me of a customer that bought a new 2005 LLY and IMMEDIATELY took out and cut up the old exhaust system so that he could install some BIG OL' exhaust system!!!! Sounded great but the ECM cut the power back to only 2/3. HA HA HA.

All I'm saying is that you need to have a certain amountof back pressure for the EGR system to work properly. When the valve opens, It compares the MAF sensor values between a closed valve and an open valve.

Here is a description of operation taken right from GM SI.....................



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Exhaust Gas Recirculation (EGR) System Description
The Exhaust Gas Recirculation (EGR) System is used to reduce the amount of nitrogen oxide (NOx) emission levels caused by high combustion temperatures. At temperatures above 1 371

[Shed]

Duramaster,
So when I put my 4" exhaust on my 01' and pulled for the first time, I hit a hill and about half way up she went into limp mode with the SES light on. Long story short, code pulled was an overboost code. Dealership said due to the larger exhaust and intake (airaid). Said there was nothing they could do about it, but said maybe an 02' "reflash" would take care of it. JK of Kennedy diesel suggested his custom tuning, which I really like the sound of, but of course with 4 kids money is tight for MY toys! Just wondering what your expirienced take is on my problem. Thanks for any help.
Shed:o

[Kennedy]

Duramaster,
So when I put my 4" exhaust on my 01' and pulled for the first time, I hit a hill and about half way up she went into limp mode with the SES light on. Long story short, code pulled was an overboost code. Dealership said due to the larger exhaust and intake (airaid). Said there was nothing they could do about it, but said maybe an 02' "reflash" would take care of it. JK of Kennedy diesel suggested his custom tuning, which I really like the sound of, but of course with 4 kids money is tight for MY toys! Just wondering what your expirienced take is on my problem. Thanks for any help.
Shed:o


This can be done in a simple 2002 stock flash also, but may as well go for the gusto...

[Shed]

Thanks JK! I'm in agreement with you! I have pitched the "NEED" for your tuning to the wife, she's skeptical. Do you do marriage counseling if she does'nt buy into the "need" part of this? Bet that won't be cheap! Hopefully i will be able to talk with you this summer and get my beast "tuned up" by you! Thanks for the info! Shed:D

[moss6]

Thank you Duramaster, thats exactly the kind of information that I am looking for and makes a good start at the understanding of the system. One thing that stands out to me in their explanation is that the mass air flow sensor is the main regulator of the valve; I have a hard time grasping how this is such a good guage of cylinder tempreture other than some correlation of some map of oxygen ratio to fuel amount equals a certain BTU---must be more to it than that. I'm with Kennedy on not liking the fact that my engine is feeding on its own feces, but I'd still like to be far more knowledgeable in order to competently evaluate the options available or be able to engineer some of my own.
Thanks again, and any additional input would be appreciated.

[Duramaster]

uhhhhhhhhhhhhh............. At first we were talking about an LBZ and now you are talking about an LB7?................ I have seen lots of customers come in with LB7's and 4 inch exhaust with no complaint whatsoever. Some even have removed the catalytic converter and muffler (straight 4 inch pipe). Sounds awfull too!

On the other hand, I also like to make sure that the software is the most current before leaving the dealership unless they have installed an aftermarket "WARRANTY VOIDING" product:D , then I leave well enough alone.

[moss6]

noooooooooo..........I never even mentioned an LB7; as I originally stated I have an 06 LBZ and the primary goal is better fuel mileage and less heat if it can be done without any apprecable additional exhaust noise. What I definately don't want to do is screw things up by over-riding a part of the original equipment that actually makes a difference. Without a complete understanding of the entire system and all its internal links--and pros and cons, there is no way that I can make an intelligent decision.

[Duramaster]

My bad. That was "SHED" that mentioned the 2001.:rolleyes: