is it better to gut my cat on a stock rebuilt engine it's a 94Z A4 wtih one cat. will it mess up my O2 readings? i got the LM1 on my car. will i have any back pressure if i cut it off? or should i buy a catco from summit for 50 bucks and have it welded on there. i'm not planning on doing any performance yet. what do you guys think. will i need it for the back pressure to get off the line and won't affect my torque? i have the stock manifolds on there.

 

It won't affect your 02 readings, it won't affect your "backpressure", it won't add gobs of power by gutting it.

It will affect your emissions, it will affect the exhaust note of your car by most likely adding a degree of raspiness.

 

If you are going ot remove your cat, do it right and put in a straight piece of pipe. I have heard that simply gutting it can actually hurt flow because of the turbulence created by the hollow chamber (read: flowmaster), and the cat body will create more rasp than a straight pipe. I am running a straight 3" pipe where my cat was and a magnaflow muffler and its nice and mellow. Once in a while I'll notice some rasp but nothing too bad.

That setup will so be gone anyway and replaced by true duals.

 

You can gut them, but it will put a REAL nasty drone inside your car.
Trust me, it will make your car annoying as hell on long drives.

 

i don't have to worry about emissions so i will put a strait pipe. does this affect the torque becasue i have the LM1 with a resonator not a traditional muffler. i heard that it affected the launch on a 94Z because it was too free flowing. is this true?

 

No, you will be fine. Removing the cat will free up very little if any power. Long story short, its not going to make a huge noticable difference in the drivability of the car.

 

Gut the cat. It sounds fine and it doesnt disrupt the flow. Flowmasters chambers have baffles and that drone you hear is your crap flowmaster muffler. It is not going to affect your torque, who have you been talking to anyway. Gutting that cat will give you a noticable gain, and you dont have to spend money for a straight pipe thats pointless.

 

did you have this setup? how did you like it?

 

Is there something wrong with the cat, is it plugged up? If not just leave it be. If you must do something, put a test pipe in or what people are calling a straight pipe. DO NOT gut the cat, bad idea.

 

Why is it a bad idea?

 

my cat is clogged so i have to do something about it. i have the LM so i think i am going to run strait pipe.

 

Yes.
Both my cats were getting clogged up so I gutted them and bought the sims so the check engine light would stay off.
The performance was like night and day, so was the sound inside the car.
It drove me insane!!! I used to drive my car on alot of long trips and that hollow drone from the front was brutal.
You are better off putting straight pipes in their place.

 

it wasn't too fre flowing? i think i will go with this setup

 

What a bunch of pussies. If you want a quiet car then get a V6. What are yall gonna do when you put headers or a cam in your car, bitch about the noise then. Gutting the cat barely makes a noise differance in the interior. It changes the tone, makes it a little raspier and a little louder, and gives you more power. I am confused as to why you think a straight pipe in place of a gutted cat will make such a differance in the noise level that it warrants spending $150-200 on parts and labor when its all said and done. Unless you planned on welding it yourself, then you save the $50-70 in labor. This is probably the dumbest conversation ive been apart of on this forum. If your cars are too loud then turn the radio up or get rid of them and get something a little quieter so you can take it on long road trips again.

 

If it is clogged, then yes, put in a straight pipe, or if you want to stay emissinons friendly, opt for a high flow cat from Catco, Carsound, or Pypes.