Gutting High Flow Cats

[NoLimit95]

Can this be done fairly easy? I live in Alabama and emissions inspections don't happen here where I live. I don't have emissions stickers or w/e in my windshield. I just want to know would it hurt anything to gut the high flow cats to reduce the restriction.

I want gutted cats, piped from there down to 2 X-pipes and then piped out the back with 97 or 98 tips. I do not want a loud car but if stomped, I want it to be heard. Not looking for the Mustang GT sound. I'll choose the mufflers when that time comes. Keep in mind, we don't have to deal with emissions here.

Any advice?

 

[Aquabrit]

I don't like the idea of gutting a cat, as you end up with a big, hollow chamber which I've heard can actually impede flow. (due to gas expansion and cooling)

Would prefer to substitute cats for straight pipe, but not sure how possible that is on the one side that has the one piece manifold / cat. I guess that's when the stock Cobra manifolds are useful.

Just my 1 cent...

Edit: Now I come to think of it, the area of pipe right after the cats is really small in diameter - that's a definite restriction area which could be eliminated by having correctly sized pipe in it's place.

 

[NoLimit95]

Why is it always something that holds you back lol? What about a partial gut? Just punch a hole through it enough to know that there are never any worries of it stopping up later down the road. I have seen the screen inside one end but I don't know what it looks like inside that.

 

[Icarus]

If you punch just a hole through the substrate, the rest will break up and clog the exhaust. Having a chamber thats hollow like 93' said will make it sound prpobably worse too. I gutted the cat on my Escort as it was getting plugged and now it sounds like a freakin deisel till it's warmed up and even then it's still tinny sounding.
Another thing is some cats have the substrate wrapped in mesh and can be a real pita to gut.
If you have no emmisions and really want to get rid of it, put a straight pipe in it's place. The cats on most cars though quiet down the exhuast more than the muffllers do though. Why would you want to get rid of it anyways?

 

[NoLimit95]

I have a strange feeling that one if not both are on the verge of clogging up. I might just remove them and go with straight pipe or flex pipe (stainless) and then take it into the double X and find some decent deep sounding mufflers but I still want some 97 or 98 tips. I don't like big round tips sticking out. Trying to keep it looking low profile but sound good at the same time. BTW, right now I am running on a muffler delete. It sounds good like it is but not quite as deep as I would like and entirely too much drone inside the car. Other than that, I really like the sound. Thinking of getting some extensions to complete it out the back and then adding the tips I'm looking for to see what type of sound I have, with hopes of eliminating some of the drone.

 

[MediumD]

Remove them and sell them for scrap. Even though scrap prices are down they'll still fetch a decent bit of money.

 

[MERIJONS97LSC]

I don't like the idea of gutting a cat, as you end up with a big, hollow chamber which I've heard can actually impede flow. (due to gas expansion and cooling)

Would prefer to substitute cats for straight pipe, but not sure how possible that is on the one side that has the one piece manifold / cat. I guess that's when the stock Cobra manifolds are useful.

Just my 1 cent...

Edit: Now I come to think of it, the area of pipe right after the cats is really small in diameter - that's a definite restriction area which could be eliminated by having correctly sized pipe in it's place.

I agree.

by the way Martin...it's two cents, not one..:shifty: if you can't speech the language get out of the country:shifty: :leghumper :waving:

If you punch just a hole through the substrate, the rest will break up and clog the exhaust. Having a chamber thats hollow like 93' said will make it sound prpobably worse too. I gutted the cat on my Escort as it was getting plugged and now it sounds like a freakin deisel till it's warmed up and even then it's still tinny sounding.
Another thing is some cats have the substrate wrapped in mesh and can be a real pita to gut.
If you have no emmisions and really want to get rid of it, put a straight pipe in it's place. The cats on most cars though quiet down the exhuast more than the muffllers do though. Why would you want to get rid of it anyways?

:I I done it to my84 corvette..WHAT A MESS!

 

[Psychostang]

There is no reason to gut the cats. If you don't have any problems with the engine, they are probably not clogged. All modern street engines need some back pressure to function properly. You will actually lose some power and torque.

 

[NoLimit95]

There is no reason to gut the cats. If you don't have any problems with the engine, they are probably not clogged. All modern street engines need some back pressure to function properly. You will actually lose some power and torque.

Engine runs smooth and I guess removing the 3rd cat and res and filling that hole in with 2 X-pipes should be enough. The muffler is going to be the hard choice for me because I want a certain sound. I don't want it loud or raspy, just a deep sound and I don't know if I'll get that with 97/98 tips or not. Maybe Flowmaster 40's will be close enough.

 

[Aquabrit]

I agree.

by the way Martin...it's two cents, not one..:shifty: if you can't speech the language get out of the country:shifty: :leghumper :waving:

Yeah John, but, you're rich! I'm just a poor immigrant that can only afford to give up 1 cent! :lol:

 

[lscmkviii]

The muffler is going to be the hard choice for me because I want a certain sound. I don't want it loud or raspy, just a deep sound and I don't know if I'll get that with 97/98 tips or not. Maybe Flowmaster 40's will be close enough.

I had 2 in and 2 out flowmaster 40's and I loved the sound! I changed everything when I put the Kooks headers on. I miss the 40 series sound.

 

[Cheez_94]

If you need the cats to be seen cause of the inspection than gut them and run a tube through them. If that is too much trouble than bite the bullit and buy some high flow cats. If you already have high flow cats why would you want to gut them?

Oh yeah why 2 x pipes, isn't one enough?

 

[NoLimit95]

If you need the cats to be seen cause of the inspection than gut them and run a tube through them. If that is too much trouble than bite the bullit and buy some high flow cats. If you already have high flow cats why would you want to gut them?

Oh yeah why 2 x pipes, isn't one enough?

1. Wanted to gut so there would never be any worry of them stopping up.

2. I don't have inspections where I live.

3. 2 X pipes because I don't like drone inside the car. 2 of them reduces that without restriction. A lot of people on here have 2 X's for that same purpose.