I have a 04 LB7 and as the exhaust curves to go out it has a HUGE catalytic converter, much like the brand new 6.doh F-250's. My truck was not made at the Texas plant, is that thing suppose to be there. Is it hurting me for power..

You must have a CA truck -- you should be able to confirm this using your VIN number (sorry, I don't now what VIN standard is used to specify a CA truck).


Both the CAT as well as the stock muffler are highly restrictive -- especially if you modify the truck.

IIRC, prior to 01/01/04 your truck must have the required emissions equipment mandated by the Federal and 49 State authorities. After 01/01/04, all vehicles for all states would have the same emissions equipment (Cats and EGRs +). The state where you bought your LB7 truck must have had an emissions equipment requirement like CA. I live in Utah (formerly from CA) and when I purchased my '04 in December, it was delivered without Cat or EGR.


A Cat "test pipe" will fix part your restrictive exhaust flow problem.

If I order a 3.5" or 4" down pipe then do a test pipe for the muffler, do you think my GMC dealership will have a problem with it? Im here in Houston, so there is no emission problems from it.

Powell, I think if you do what I did and just cut out the muffler and then remove the cat you should not have any issues. I did not have a cat so that was not an issue with me at all. Sorry to hear you have a kitty under your truck, better kill it quick. http://www.dieselplace.com/forum/smileys/HiHi.gif

My understanding is only the CA '03 trucks got CAT's but all the '04's where supposed to have them. But hey, I've been wrong before!!!!

My understanding is only the CA '03 trucks got CAT's but all the '04's where supposed to have them. But hey, I've been wrong before!!!!


Depends on whether '04 truck is an LB7 or an LLY. I have a '04 non-CA LB7 and it didn't have a CAT...


As far as the laws regarding the removal of emissions equipment from a CA truck in a non-CA state I have no idea. I doubt anyone would ever notice so it is probably a moot point anyway.


Of course this means that the truck has EGR as well -- right? Not sure how hard this would be to remove, but depending on laws and how serious you are about performance you may want to remove it as well.

I have an 03 with a cat and I am in Georgia. There are no laws for them inthe state at this time.


If you take off the cat I hear http://www.dieselplace.com/forum/smileys/Wink.gif that they can be hollowed out with a pipe.


From what I have been told...wink wink...a piece of 1" galvanized pipe and a hammer will clean that sucker right out and all you will have left is a resonance chamber. FREE FLOWING! The turbo will spin up a little quicker. Not sure about exhaust temps as I ...um or the feller who told me this doesn't have an EGT guage as of yet..





Mike

I have a CA 2002 which came with a CAT. I purchased/installed the Banks 4" exhaust which connects at the down pipe (Removes the CAT). My truck has been to the dealership twice since the install. The truck has been up on a lift for oil changes and differential service. The dealer hasn't said anything about the missing CAT. I spoke with one of the diesel mechanics about my exhaust system. He had no problem with it and said it will perform better with an aftermarket exhaust system. The service writer said the only issue would be the emmission system or lack there of. Meaning the new exhaust would not be covered by GM. NOW, If I have an EGR problem will that be covered?


One thing nice about the Banks system, I can reinstall the CAT in about 30 minutes if needed.


ChrisEdited by: CMDMAX

I have a question here,


I have an early '01 Cal delivered truck. It never came with a CAT, it just has that 55 Gallon Drum looking muffler. From what I understand from postings in the past that the '01's really essentially had nothing in regards to emissions controls including EGR's. I had a person late in '02 that wanted to swap me trucks as he wanted a Emission exempt truck as the '02's and beyond required an emission check in California. he wanted to modify away and not worry about State reg's. Is any of this true? I am more curious than anything.


I have not received any notification for an Emission check for my truck to date.


Thanks


Jeff

I talked to the dealerships around here and they said that they can not remove it, but to goto a muffler shop and have them remove it. Or I could install an aftermarket exhaust system. How much power do you think the truck could be losing if I were to put a programmer or a module on it?

I'll take a S.W.A.G. (I don't know of any test results to support this). If you remove the CAT and replace the muffler with either a straight pipe or a muffler that flows like one, you will likely get a 20 to 30 horsepower increase along with a 125 to 150 degree reduction in EGT (under some conditions with some tuner or module someday, somewhere). Then, if you add an AFE Stage II or similar aftermarket intake your turbo sound like a jet, but I doubt that you will see any change in either performance or EGT (some say the turbo spools quicker, but I don't see it). Hope this helps. http://www.dieselplace.com/forum/smileys/Big Smile.gif

Duramax Dually,


As of this time there isn't any emission testing of diesel pick ups in California


Michigan Joe,


At the very best your not even likely to see a 15 hp. increase. It does lower the e.g.t.s though. tpitt

At the very best your not even likely to see a 15 hp. increase. It does lower the e.g.t.s though. tpitt





Depends on the truck. A stock truck might only see 15 hp (and I bet it would), but what about one making 600 horsepower? Forced induction minimizes the horsepower gains obtained from intake and exhaust modifications, but the stock muffler itself is very restrictive. Add a CAT to the mix and the exhaust becomes substantially more restrictive.

My understanding is that only the '01's came without a CAT in CA.


Any truck made for sale in CA after the '01 model year came equipped with a CAT.

Blinky,


Thanks, and your input agrees with what I heard. I would have to say that if their are no emission checks in CA then would it not make great sense to remove the exhaust entirely and make it flow properly?


Is there a worry that they might get caught with a modified exhaust?


Jeff

Hi all:

If it matters, I spoke with the Air Resource Board in Sacramento before I bought my out of state truck. True, there is no Ca smog for diesels...yet. Wait until 2006, it's coming.

If you remove that CAT in Ca., make sure you save it and put it back on for that smog test in a few years.

Best,

Dan

My '04 built in 10/03 for sale in Washington State does not have a cat.

My '04 built in 9/03 for sale in Indiana DOES have a cat.http://www.dieselplace.com/forum/smileys/Angry.gif
Anyone out there have a definitive answer on why some LB7s have a cat & some don't? Crew Cabs don't & Ex. Cabs do? What gives?

You guys got me wondering about my truck, now. Guess I'll have to crawl under it and check it out ( when I get back home from Portland, Oregon -- nice little town ). I don't think it has a cat, and it's a '04 LB7 Texas truck and I think it was built 9/03.

Mt 04 CC daully dosen't have a cat am from Maryland and the truck was build for a dealer in N C.... 10/03

For emissions, you can look at the "factory build codes" on the sticker in the glove box. The following applies for the LB7:


FE9 - Federal emissions - no CAT or EGR includes 2001 - 2004


YF5 - Calif emissions (2001 no CAT or EGR) (2002-2004 has CAT & EGR)


NE1 - Mass & Maine - at some point they picked up the CAT & EGR, same set-up as California package.

Thanks for the info OC_DMAX, but my build sheet doesn't have any of those codes. Any other suggestions?

For emissions, you can look at the "factory build codes" on the sticker in the glove box. The following applies for the LB7:


FE9 - Federal emissions - no CAT or EGR includes 2001 - 2004


YF5 - Calif emissions (2001 no CAT or EGR) (2002-2004 has CAT & EGR)


NE1 - Mass & Maine - at some point they picked up the CAT & EGR, same set-up as California package.





What he said


Bill

Thanks for the info OC_DMAX, but my build sheet doesn't have any of those codes. Any other suggestions?


My truck has the LB7, built in 10/03 and has no cat.http://www.dieselplace.com/forum/smileys/Big Smile.gif Maybe they just selected trucks at random to have a cat.http://www.dieselplace.com/forum/smileys/Clown.gif But seriously, I thought all vehicles had to have a label on them somewhere stating that they were emissions compliant in the area they were built for. I would say if you don't have one of the codes that says your truck was built with a kitty, take it out.http://www.dieselplace.com/forum/smileys/Approve.gif Do you have EGR?Edited by: flhrciblueice

Thanks OC,


Mine shows the YF5 code, So I can do what I want and they can inspect all they want. Makes me even happier I bought an '01.....No Cat...No EGR....keep it simple...http://www.dieselplace.com/forum/smileys/Clap.gif

Do you have EGR?

I've looked for the EGR & couldn't find one, but that doesn't mean I didn't overlook it. Where exactly is the EGR on an LB7?

Thanks OC,


Mine shows the YF5 code, So I can do what I want and they can inspect all they want. Makes me even happier I bought an '01.....No Cat...No EGR....keep it simple...http://www.dieselplace.com/forum/smileys/Clap.gif





This is one of the biggest reasons I bought an '01.... No CAThttp://www.dieselplace.com/forum/smileys/Approve.gif

As of 2004 all duramax engines will have EGR valves, Cat's, Variable displacement turbos. GM is stepping foreward towards meeting the EPA deadline for diesel emmissions requirements.

As of 2004 all duramax engines will have EGR valves, Cat's, Variable displacement turbos. GM is stepping foreward towards meeting the EPA deadline for diesel emmissions requirements





That is the LLY version of the Duramax diesel.

That is the only one currently in production for GM light duty trucks.

As of 2004 all duramax engines will have EGR valves, Cat's, Variable displacement turbos. GM is stepping foreward towards meeting the EPA deadline for diesel emmissions requirements.


I think the point here is that you've made an inaccurate statement...http://www.dieselplace.com/forum/smileys/Ermm.gif


While there are quite a number of members who understand the difference between the LLY and LB7 engines and when they were available, not all who come here looking for answers are aware of that.


Since the LLY variant was not available on dealer lots until late December because LLY production didn't start until about the 10th of December, to say that all 2004 Dmax engines are the LLY is incorrect. That is important for those who seek aftermarket modifications since very few mods for the LB7 work on an LLY. Also due to the hardware, software and engine component differences, there are differences in troubleshooting techniques and problem solutions.Edited by: Zeeb

I think the point here is that you've made an inaccurate statement...http://www.dieselplace.com/forum/smileys/Ermm.gif


Since the LLY variant was not available on dealer lots until late December because LLY production didn't start until about the 10th of December, to say that all 2004 Dmax engines are the LLY is incorrect. That is important for those who seek aftermarket modifications since very few mods for the LB7 work on an LLY. Also due to the hardware, software and engine component differences, there are differences in troubleshooting techniques and problem solutions.


well I never said all 2004's i said as of 2004. so if you want the job of correcting me. at least be accurate and not mis-quote me.

Most people refer to the year of a vehicle by the model year. You do nothing but confuse some folks with statements like the one you made even though it is technically accurate.


Do you happent to be related to the SM at the dealership where my GMC came from? Because your attitude and his are very similar. Trust me, no one I know or talk to about GM trucks will buy anything from that dealer.

<---- 2004 LB7 no feline

Hey now DMAX owners...easssssssy does it...We all come to this and other sites to get information. Best we can hope for is the individual who is posting offers FACTUAL information, but we are still required to use our common sense. I think the above 2 were simple verbage issues and do not take away the fact that essentially 2001's were ALL void of Cats and EGR's, then 2002 - 2003 were all over the place based on the latest Gov reg's for emissions and the state in which they were delivered. 2004's got a little more complicated with the release of the next Gen motor, but some '04's were made with LB7 options.


Play nice.....http://www.dieselplace.com/forum/smileys/Big Smile.gifEdited by: Duramax Dually

My 03 came with the Mass emissions package with the cat. I just ordered the pipe without the cat for a 49 state truck and it bolted right in. Running edge juice it dropped exhaust temps 100 degrees while pulling on hills. Also lower my 1/4 mile ET

I have a 2004 LB7 in CA with cat & egr.


Build date is Sept 03


BillEdited by: Redapple