Gutting the Cat Converters

caseycamby

caseycamby

Suspension Lift
Location
Marion, NC
I've some questions. I've been doing some research but I still haven't found clear answers.

I've concluded the cat(s) are bad. My plan now is to just remove and not replace.


1) Would I be better to just gut them, or completely remove them and have a straight pipe welded in? Or does it really matter?

2) How differently will the X act? Will I still have enough backpressure? I'm assuming there will probably be a code, as well..


2001 Xterra 3.3, by the way. Any other advice or help is appreciated!
 
caseycamby

caseycamby

Suspension Lift
Location
Marion, NC
Good call on the eliminators.

Just started thinking.. Isn't the first cat almost made into the exhaust manifold and I wouldn't be able straight pipe it? I could still completely remove the secondary but maybe just gut the first one?
 
Prime

Prime

Shut up Baby, I know it!
Admin
Location
Denver Adjacent
caseycamby said:
Good call on the eliminators.

Just started thinking.. Isn't the first cat almost made into the exhaust manifold and I wouldn't be able straight pipe it? I could still completely remove the secondary but maybe just gut the first one?
Click to expand...
Long tube headers. Problem solved.
 
granitex

granitex

Skid Plates
Founding Member
Location
Columbus OH
I found that it was cheaper to do the long tubes than it was to do one of the cats, makes the decision really quick for me. Other than that a down tube would be a bolt in solution instead of trying to weld on the manifold, which is not a really good option. Trying to weld on a cast manifold is not something for a beginner and not worth it for most pros.

other than a test pipe, which is what you will have to call it when you have it made, long tube headers are the best option.
 
Mirage

Mirage

<img src="http://i164.photobucket.com/albums/u7/ra
Founding Member
Location
Greenville SC
You can also get the '00 Federal Downpipes from walker for a reasonable price, that specific variant didn't have secondary cats in the downpipes. Those+headers=awesome.
 
caseycamby

caseycamby

Suspension Lift
Location
Marion, NC
Mirage said:
You can also get the '00 Federal Downpipes from walker for a reasonable price, that specific variant didn't have secondary cats in the downpipes. Those+headers=awesome.
Click to expand...

You're right. Here's the diagram I get at work, I think you guys can see it (LINK)

I'm working with a guy right now who runs an exhaust shop and I'm thinking if he can install the headers, then make custom pipes until where ever, maybe where the Gibson catback exhaust runs to, I'll be golden.
 
Xaggerated

Xaggerated

Tricycle
Location
Greer, SC
I personally wouldn't pay for the header install. As for piping ID just take it to a shop and figure out what you want. As for the side pipes, the gas tank is in the way so they'd have to exit under the front doors which is less than ideal.
 
MichaelS75

MichaelS75

Bought an X
Location
Charlottesville, VA
My plan is kinda like yours. Except I was planning on leaving the primaries, cutting out the secondaries and welding piping in there place. This shouldn't throw a code since O2 sensors are in front of it. Eliminates the heat shield rattle and still leaves primary cats. I could probably sell the secondaries and make some money back for new exhaust as well.
 
Mirage

Mirage

<img src="http://i164.photobucket.com/albums/u7/ra
Founding Member
Location
Greenville SC
Prime said:
They are shorter than the ones with cats. So you'll need a whole new Y pipe too. So bear that in mind.
Click to expand...

I've got AC headers, said walker downpipes and nismo y-pipe/catback on my '03 SC. Just took a little adjusting to the catback to get everything sitting right again, still using the trans to y-pipe mount even
 
Xaggerated

Xaggerated

Tricycle
Location
Greer, SC
Mirage said:
I've got AC headers, said walker downpipes and nismo y-pipe/catback on my '03 SC. Just took a little adjusting to the catback to get everything sitting right again, still using the trans to y-pipe mount even
Click to expand...
Didn't know you were still on here. You still in the upstate?
/threadjack
 
Mirage

Mirage

<img src="http://i164.photobucket.com/albums/u7/ra
Founding Member
Location
Greenville SC
Prime said:
The Walker pipes I ordered were at least 10 inches shorter than the cat's versions.
Click to expand...

Weird. I'll try and figure out what part numbers I got.

Xaggerated said:
Didn't know you were still on here. You still in the upstate?
/threadjack
Click to expand...

Yea, moved to liberty. Truck is in rough shape these days, trying to get the car running so I can take the truck off the road to fix all its issues.
 
caseycamby

caseycamby

Suspension Lift
Location
Marion, NC
CEL eliminators ordered. I believe, for now, I'm just gonna have the primary cats gutted and then a completely new pipe to take place of the secondary cats and that's where the CEL eliminators will be installed.
That's the plan for now. I'll be saving pennies for the DT headers :sure:
 
rawkerstatus

rawkerstatus

Bought an X
Founding Member
Location
Santa Ana, SoCal
Did you ever get this figured out? i need to ditch the secondary cats but because of emissions i dont know if a shop will cut them out and weld on a straight pipe. this will be my next step if the test pipes didnt work out.

/zombiethread
 
K

KBC

Bought an X
Location
BC
I have an '01 with the headers that eliminate the first pair of cats and then I used the pipes for an '00 to replace the second set of cats. Everything bolted right in. I also replaced the y pipe with one from walker and did the gibson performance exhaust. I definitely have more power and better gas mileage but I think the mileage is from the fact that I hate the sound of the Gibson muffler so I stay off the gas more.

I think my drivers motor mount is shot though because two y pipes have broken at the welds in the past 6 months. I have one of the broken ones that I welded back together in right now and am putting the new motor mount in this week. If that holds up for awhile I have a brand new y pipe that was replaced under warranty to put back in.

I think '02-'04 used different exhaust joints than the '00-'01s so if you wanted to get rid of all your cats by doing the same thing I did, you might have to replace everything instead of just the primary and secondary ones.

Confused yet?
 
caseycamby

caseycamby

Suspension Lift
Location
Marion, NC
rawkerstatus said:
Did you ever get this figured out? i need to ditch the secondary cats but because of emissions i dont know if a shop will cut them out and weld on a straight pipe. this will be my next step if the test pipes didnt work out.

/zombiethread
Click to expand...

I actually did exactly this down below..

caseycamby said:
CEL eliminators ordered. I believe, for now, I'm just gonna have the primary cats gutted and then a completely new pipe to take place of the secondary cats and that's where the CEL eliminators will be installed.
Click to expand...

Everything is working great! I ended up getting the Walker Quiet Flow exhaust because the no cats to the Cherry Bomb was way too loud for my liking.

I actually just found out today that my passenger side exhaust manifold needs replacing. How awesome is that?!
 
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