Gutting the Primary Cat

[MR2Jedi]

I was thinking about gutting my primary cat while i have it off. what is involved.? do you just rip out the inside? and what will the benefit be? I have read where some of you guys have done this. I am assuming free-er exhaust flow and alittle quicker spool up.-correct? I don't have to worry about emissions here...comments? info? thanks guys

[celfatic]

I agree with you with the quicker spool up do to no restriction. Your lucky you don't have to do smog emissions. If you plan on doing this, shower the exhaust bolts with wd-40 to prevent from breaking. It will save you time and a head ache or two. Let me know how it sounds. I was wondering, (when there is no cat) and the car is reved up, does it pop like an srt4 or are you able to see flames? (maybe both)......
.....cuz if it does, I think I might do it too......

[NESW20]

Originally Posted by celfatic

I was wondering, (when there is no cat) and the car is reved up, does it pop like an srt4 or are you able to see flames? (maybe both)......
.....cuz if it does, I think I might do it too......

yes, it does. i helped a friend of mine gut his cat on his turbo, and when he had his BOV vented, he would shoot flames when he blew off. pretty impressive seeing 2 fireballs out of the 4" tips on his Greddy Power Extreme. but it also kind of attracts attention from the cops, haha.

-Mike

[MR2Jedi]

Hey Mike, do you think this is a worth while endeavor? any HP gains? problems? not sure I want flames blowing out of my BOV...

[ST185]

http://www.alltrac.net/tuning/exhaustfaq.html

[Zero turbo]

Originally Posted by MR2BAD

Hey Mike, do you think this is a worth while endeavor? any HP gains? problems? not sure I want flames blowing out of my BOV...

you will have flames blowing out of the Exhaust pipe not the BOV .

[MR2Jedi]

Thanks ST185.. that helps alot. and thank to the rest of you guys... you're the bomb(s)!!!!

[Strat42586]

I'm running ATSs CT-27 turbo, fuel pressure regulator, GReddy intercooler, TB inlet and ROM tune. I'm on stock exhaust with gutted cats and I'm at 225hp and 240tq (dyno'd before the TB inlet and intercooler were installed.) Sounds fine, not loud. But still doesn't do NEAR as much as an aftermarket exhaust would do for performance. My top end is still murdered because of the restricted piping and bends

[MR2crazybyong]

doesn't the wide hollow space in the gutted cat create turbulence in the exhaust flow? i would recommend custom downpipe, and its lighter too.

[Strat42586]

Naturally the space causes turbuluence, but it's better having it gutted than having both turbulence and backpressure caused by a stock cat.

[NESW20]

my friend did pick up a little quicker spool, maybe a couple hundred RPMs. and as stated above, nothing but air comes out of the BOV, the flames only come out the exhaust tips.

-Mike

[nepopolus]

i did it back when i had my 5sfe i had straight pips no cats and a custom exhaust manifold it sounded amazing and got alot better response(i dont know gains i guessed it would be a waste of a dyno with 1 upgrade)

on a 3sgte i am going to do it (right now it is going in) i am having a custom straight to a apexi n1 exhaust, so i guess i could tell you how it sounds

btw if you want to gut your cat i would get a drill the same size as your pipes and just push it though it (ghetto tuning ftw!)

[MR2Jedi]

That was my next question. how exactly do you gut it? do you just chip away at it with a hammer and chisel? what is that shit made out of anyway? I'm gonna do it tomorrow(monday) so if anyone has any helpfull tips on doing this, it would be greatly appreciated. or else I'm just gonna destroy the insides with what ever looks easy from my tool arsenal!

[BrightTundra04]

a long pipe like water line and a hammer just beat the pipe into the material till it come out

[ST185]

Soak it so it create minimal dust.
Wear a dust mask.
That stuff will kill you.