I have an 04 LB7, CA version w/ a catalytic converter.

I am currently looking at a turbo back exhaust system.

My questions are:

Do I have to keep my catalytic converter, or can i dump it?
If I dump it, will it set off any error codes?

It doesn't appear to have anything connected to it, so I don't see how the on board diagnostics would know if it is there or not...

I am a newbie here any any help would be greatly appreciated.

You will have NO problems unless you get caught as it is illegal to remove. I would just retain stock exhaust for resale and for any smog testing.Better to replace temporally or face a fine,if need be.


Welcome to the forum,enjoy

thanks for quick reply...

one other question...if I take it in to the dealer (say for an oil change) should i take the time to put the catalytic converter back in? if i didn't, would they log it in their computer that i have removed it, therefore someday when I drop it off for warranty work it would be denied.

Big fine if caught.

There is talk of adding diesel smog inspections in this state. They would check for a cat.

Will make your truck stink too.

Really minimal gains foir removing it, IMO.

Don,t you have a yearly clean air inspection in CA.

If you remove a catalytic converter it will not meet the exhaust emissions that are instantly downloaded, and analized at the governments office who instantly approve or reject the clean air test. At least thats how its done here. $37.50 Three tries and your out (no licence renewal).

good luck

If you bring it in for issues of performance ,fuel econo or anything Engine related then can or might point the finger.Most likely they wont even notice.


How would you get caught ,only by inspection?I would just claim I'm "testing" something if caught,or it's temporary while I get a new system. How many have actually paid a fine?

State Scare tactics

Kinda wierd that there is no emissions inspections yet. I have heard talk about it. Read an article that says it is coming for sure in Tx. That will surely pose a problem for some few folks. If the emissions sticker on your truck says "catalyst" you, by law, have to have a catalyst on it.

If you were to say "Im testing something" theyd laugh and write the fine.

Kinda wierd that there is no emissions inspections yet. I have heard talk about it. Read an article that says it is coming for sure in Tx. That will surely pose a problem for some few folks. If the emissions sticker on your truck says "catalyst" you, by law, have to have a catalyst on it.

If you were to say "Im testing something" theyd laugh and write the fine.

Well I should have gone into more details for you Manny,I can tell your a detail orientated guy.

Testing as in I was having run ability issues and felt that I may have a restriction,therefore hence, I were testing.So ,I would follow up with,"who new it was such a crime".Every one can play dumb once in awhile,by "accident",in case you confused by that statement. I'll bet you fear ripping the tags off your new mattress too :D

Actually in the Petro world and Catalyst, "test" pipes are sold here in CT and we have a Federal Emission Program. Yes it is illegal to run but for diagnostic purposes.I call that working with in the system.Most of us are smart enough not to go into the inspection station with a test pipe in place on the East Coast with out being told.West coast,well I can tell from your confusion, its a toss up

If I was stopped for a spot Emission compliance roadside check (never heard of one) that is where I would use my "I was testing" excuse and follow up.

Are you a slave to your Government,you can label me a civil disobedient any day :)

Is the Cat really hurting the exhaust?
My take on this is.........if you have to ask the question you are worried about what could happen if caught. I would leave it alone. You may save the environment or something. :)

Many good health/environmental effects of leaving it on, few benefits of removing it.

Or...

Remove it, and use biodiesel.

I lock the doors and shut the lights off when I tear the tags off my mattress:eek: for fear of the mattress police. I have heard that the mag wheel police are worse when you peel those tags off your new wheels.:eek: What are we to do?

mike

thanks for all the responses

my intent w/ the turbo back system is to decrease EGT and get more power. but i would be ok w/ a cat back system, if there is no real benefit to a turbo back system

i tow a 12k trailer, and don't have any mods (other than an afe II intake), but i anticipate on adding edge/juice soon

how much of a decrease in EGT's between a turbo back system vs. a cat back system vs. a stock system?

Fireresource, I heard from a customer yesterday that removed his cat, he said that he should have left it on, minimal gains, and more stink. I think unless you're doing heavy mods, you won't notice any significant gains. If you do end up removing it, and you need to bring it to the dealer, you can bring it to me, no worries, I work at a dealer in OC. I have a wierd blindness when it comes to boxes, programs, propane, exhaust & intake systems and missing cats.

i am looking for a good mechanic (not for anything specific, but just in general), where ya at?

Nicholas Chevrolet

socaldieseltech,
Will your dealership work on GMC's? I know some will and some won't. I usually take mine to Cerritos, where I bought it, because I don't think they will hassle me with the Edge but you never can be sure. Thanks

LA DMAX

hey socaldieseltech, will you work on my truck(02chevy) if /when my injectors go out, i have TTS installed & no cat????

g. corral, no problem. I wont sweat you. LA , I can work on GMC's but I did get a little probing from GM and my SM about why I work on so many GMC's. I said its not my fault the local GMC dealers suck and customers would prefer to take their trucks to me. If you just need some basic stuff done like a taillight or an I-shaft, bring it to GMC, if you need injectors or frpr or have other driveability or diesel related issues bring it to me, just give me a heads up on when you'll be coming in. Merry X-mas to all!!!

My cats in the garage (wish the truck would fit (too many parts off the truck)). No codes and I didn't notice any change in smell. I replaced the whole exhaust system at one time so I can't say what the cat got me (if anything).

Thanks Socaldieseltech..i Will Always Keep You In Mind...merrychristmas!!!!!

fireresource, Where in Lake Forest are you? I'm off of El Toro and Normandale. See my Sig, Give me a call and ask the questions. I believe Blinky is in Mission Viejo also (I still need to get a ride from him with that tranny Mike L. did for him, Are you paying attention Mike? My warranty is almost up and the funds should be available in 3-4 months!). Maybe the 3 of us can meet up and give you a ride. I belive he's running the Edge and I'm running the 6-gun. Should give you a good feel for what your looking for!

TT

Not being nearly as well-versed in diesel as the other folks here, I'll ask the obvious. Is it just California trucks that have cats or what? My '03 has a cat, and it was delivered here in Grapevine TX. It was a "support vehicle" for the 2003 Great American Race, which I think started up in Detroit.... Any thoughts??? Ironically, my DMAX smells much different from my brothers Cummins, which is an 03 also.

All LLY's have Cat's, and those LB7's that are delivered to certain states, (CA, CT, others that I can't recall), had Cat's installed.

I live in Ohio and have no cat on my LB7. I was very close to getting one of the first LLY's. It was all based on my build date and how many LB7's that had to get rid of before using the LLY's.

I am very happy I received an LB7. :D

When I installed my Banks ex system. I ordered one for a non-cat or federal truck. The cool thing about this is that the pipe is sectioned so that you could replace that cat at any time, thereby converting it to a cat-back system. Do a before an after test with/without cat and see for yourself if there is a performance gain.

You can see pics of the whole Banks system next to my stock system at the link in my sig. I even took a picture of the inside of the cat.

My cat is currently sitting on the shelf along with all my stock parts waiting for the "People's Republic of California" to begin smog testing of diesels. :D

Hi, I am new to this forum but have been following the postings on the Cat removal issue. I too live in CA and have purchased a 4" turboback exhaust system. I am trying to figure out what I should do...remove the cat or not.

I could have the cat adapted to with 3" to 4" adapters so that it would fit in my 4" exhaust system but.....My take is this...what is the point of having the 4" exhaust if the cat has a 3" inlet and outlet. Am I wasting my time and money by putting this exhaust on?

Do they make catalytic converter with a 4" inlet and outlet.

Please help, I am deciding wether to yell at the company that sold it to me, because they said it would work with the Cat...liars!!

Changing out the muffler will get you the best results. The muffler is the main problem. A 4” system will help and so will removing the cat. My whole exhaust system is leaning against the garage wall and has been replaced by a 4”. But if I need to someday I can reinstall the stock system.

Strangely enough, cats were showing up on late '01s intermittently across the country, while here in advocadoland emissionsville, they were still anti-feline. Hopefully, they'll never do the "retrofitting" the CARB nuts rant. Anybody think the anti-gun groups or PETA or the tree-huggers are fanatic? Check out the CARB website!

Fireresource, I heard from a customer yesterday that removed his cat, he said that he should have left it on, minimal gains, and more stink. I think unless you're doing heavy mods, you won't notice any significant gains. If you do end up removing it, and you need to bring it to the dealer, you can bring it to me, no worries, I work at a dealer in OC. I have a wierd blindness when it comes to boxes, programs, propane, exhaust & intake systems and missing cats.socaldieseltech, why don't you move to Maryland. :welcome2:

Hey Socal...where in Orange county are you? Do you know anyone good down in the San Diego area, preferrably North County? Thanks. I may come to see you for work instead of the dealership here. Hopefully you could take another GMC?