Cutting the catalytic converter, few questions before I decide - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums

Fhawk362 · 02-01-2009, 04:13 PM

I want to cut off my catalytic converter and would like to find out a few things first. 1. how much should it cost me, i dont have any hook-ups and will have to go to a local exhaust shop. 2. I'm mostly doing it for a louder rumble, will it sound nicer without the cats. 3. Not so important, but what type of gains should I get out of it, both in E.T. and horsepower: current mods in sig. 4. I live in FL and there are no emissions here so is it still illegal to do here?

Thanks for any help in answering my questions.

XtremeOracing · 02-01-2009, 04:21 PM

Quote:

Originally Posted by Fhawk362

I want to cut off my catalytic converter and would like to find out a few things first. 1. how much should it cost me, i dont have any hook-ups and will have to go to a local exhaust shop. 2. I'm mostly doing it for a louder rumble, will it sound nicer without the cats. 3. Not so important, but what type of gains should I get out of it, both in E.T. and horsepower: current mods in sig. 4. I live in FL and there are no emissions here so is it still illegal to do here?

Thanks for any help in answering my questions.

I live in FL too, it might be illegal to cut them but who cares there are no emission laws here! i don't remember noticing a gain as far as HP when i cut them out before getting headers but, it did sound deeper...

They charged me $40 to do it.... and i gave the mechanic who did it $20 tip ... so grand total ! 60 bucks.

ShowNoMercy · 02-01-2009, 04:30 PM

If you get it cut out and not just "gutted" it prob will make your exhaust louder but more raspy too. As for legal issues, its a federal crime so whether or not your state checks is hogwash. If you get pulled over and for some strange reason the cop checks, big fine/impound vehicle/off to jail time. Granted I am being extreme, but in all reality, its just not worth the maybe 10hp you get. If you get rid of the stock manifolds then by all means ditch the cat.

steveo · 02-01-2009, 04:40 PM

as a general rule, stock manifolds + cat delete + flowmaster catback sounds pretty rough

you might want to find a dead cat somewhere and gut it, and just bolt it up to see if you like the sound before you put too much effort into deleting it properly

Fhawk362 · 02-01-2009, 05:38 PM

Quote:

Originally Posted by ShowNoMercy

If you get it cut out and not just "gutted" it prob will make your exhaust louder but more raspy too. As for legal issues, its a federal crime so whether or not your state checks is hogwash. If you get pulled over and for some strange reason the cop checks, big fine/impound vehicle/off to jail time. Granted I am being extreme, but in all reality, its just not worth the maybe 10hp you get. If you get rid of the stock manifolds then by all means ditch the cat.

If i get it gutted will that make it sound better? How do you gut one? On the free mods section of this website it said to cut it out and put in a straight pipe but that doesn't seem to be what youre telling me gutting is.

philosophico · 02-01-2009, 06:56 PM

Quote:

Originally Posted by Fhawk362

If i get it gutted will that make it sound better? How do you gut one? On the free mods section of this website it said to cut it out and put in a straight pipe but that doesn't seem to be what youre telling me gutting is.

Gutting it is essentially removing the cat and removing the guts inside it then putting it back on, some people do this so they can pass the mirror test.

ShowNoMercy · 02-01-2009, 07:45 PM

Yup, and it will sound horrible.

Fhawk362 · 02-01-2009, 10:20 PM

Quote:

Originally Posted by steveo

as a general rule, stock manifolds + cat delete + flowmaster catback sounds pretty rough

you might want to find a dead cat somewhere and gut it, and just bolt it up to see if you like the sound before you put too much effort into deleting it properly

ok, maybe deleting the cat aint the best idea. Do you, or anyone else for that matter, have any suggestions on how to get my car sounding better and maybe gain some power that doesn't cost a fortune. I'm a college student with a part time job and not much money so any suggestions. Also, any suggestions for just random little mods or fairly cheap mods Im all ears as well.

Fhawk362 · 02-01-2009, 10:21 PM

Quote:

Originally Posted by ShowNoMercy

Yup, and it will sound horrible.

ok, maybe deleting the cat aint the best idea. Do you, or anyone else for that matter, have any suggestions on how to get my car sounding better and maybe gain some power that doesn't cost a fortune. I'm a college student with a part time job and not much money so any suggestions. Also, any suggestions for just random little mods or fairly cheap mods Im all ears as well.

94 Z28 · 02-02-2009, 12:16 AM

Sound wise your best bet would be to save up for some LT's not to mention you'll get a couple extra ponies out of it.

ShowNoMercy · 02-02-2009, 06:36 AM

Cheap, loud and maybe some power could come from a cutout.

MY94ZZZ · 02-02-2009, 07:57 AM

How would gutting your cat make it sound horrible?
On my ret. 94 Z28 A4 I was running some BBK shortys and down pipes with my cat gutted and my god it sounded mean as hell!!!
That is vs what is sounded like with just a single mandrel bent 3inch cat back with a flowmaster muffler and custom tips!

Quote:

Originally Posted by ShowNoMercy

Yup, and it will sound horrible.

ShowNoMercy · 02-02-2009, 09:23 AM

Quote:

Originally Posted by MY94ZZZ

How would gutting your cat make it sound horrible?
On my ret. 94 Z28 A4 I was running some BBK shortys and down pipes with my cat gutted and my god it sounded mean as hell!!!
That is vs what is sounded like with just a single mandrel bent 3inch cat back with a flowmaster muffler and custom tips!

Shorties, downpipes? and no cat? WTH kinda exhaust was that?

And gutting the cat creates a big box for exhaust flow to be hindered. Ever wonder why aftermarket stuff is smooth with no kinks or other flow challenges?

MY94ZZZ · 02-02-2009, 10:50 AM

Well lets see here if you know anything about exhaust you woulden't have asked that question. but i know you do know alot about LT1's? Maybe in jersey that different words for different things.
So you have the shorty headers, then the two pipes on on each side that lead into a y, then stright into your 3 inch cat delete pipe. what don't you understand about that exhaust system??????????????????

Quote:

Originally Posted by ShowNoMercy

Shorties, downpipes? and no cat? WTH kinda exhaust was that?

And gutting the cat creates a big box for exhaust flow to be hindered. Ever wonder why aftermarket stuff is smooth with no kinks or other flow challenges?

ShowNoMercy · 02-02-2009, 11:12 AM

Quote:

Originally Posted by MY94ZZZ

Well lets see here if you know anything about exhaust you woulden't have asked that question. but i know you do know alot about LT1's? Maybe in jersey that different words for different things.
So you have the shorty headers, then the two pipes on on each side that lead into a y, then stright into your 3 inch cat delete pipe. what don't you understand about that exhaust system??????????????????

Downpipe is a term guys with with turbos use to describe the pipe from the exhaust port on the turbo to the catback or whatever they run. What you have would be more commonly called a "Y pipe or ORY" not a downpipe. And I was referring to gutting the cat, which would keep the stock cat housing and remove its contents, which will create a lot of bad turbulence in your exhaust flow and more than likely hurt performance.