gutting the cat

[Guest]

ok....im actually gutting the cat, to free up the exhaust more w/o the parents knowing..so im wondering how much louder will it be...i can do this at my school believe it or not so...im just worried about how much louder it will be, i already have a cherry bomb on there, and its been on for about a year, pretty much blown out...heheee. so, lemme know, and im sure there will be a performance gain...any one know how much?

[Guest]

IMHO, your six should benefit pretty well from the gutted cat. Particularly if your cat was clogged in the first place I originally was running dual targa mufflers on my 'vette with a walker rear crossover y pipe and decided it was time to gut the cat [both for sound and performance]. I know my friend w/ the same year did it to his and picked up about 20 ponies at the flywheel. Pretty good for just gutting it eh? Anyways, the sound is magnificent! Loud, and very ballsy. Nice tone too. As far as your six will go, since your running a glass pack, I'd imagine it will be quite the loud six cylinder I've been in my friends '92 Supra [before the current body style] and he has a turboed six with a gutted cat and true duals. That thing is loud, but definitely not annoyingly loud. I think your car would be along the same lines. Give it a shot, the worst that can happen is that it can be way tooooo loud and you'll have to get a new one [and in that case buy a high flow! ].

As for the power aspect of it, I think you should notice the gains. You'll be pretty much employing a straight through exhaust system, and I think that the 3.1's benefit pretty well from a straight-through exhaust system [I'm going to have to try it on my '91 if I ever start making some decent money while still in college ].

Anyways, good luck Scott
-Steve

[Guest]

that was one of the best responses ever!!! lol...i hope its not too loud, if my dad thinks something is up, ill just tell him my cat must be falling apart     then when he takes it off and sees its perfectly hollow.....quote scott " how did that happen!!!"  

[zach82]

LOL... my dad helped me cut mine off... he let me use his disc cutter, and he held the pipe up while I cut.  He thinks they are the worst POS to ever be put on a car.

When I removed mine, I'd say I gained about a 30 percent volume increase... maybe more, maybe a little less.  Makes a huge difference in the car too, a lot of droning rumble and more vibration.

[98beretta kid]

my friend Jason has side exhaust (from JC whitney) on his 82 camaro and if your car sounds anything like his does (loud and mean) then im gutting my cat

[Guest]

You need to stop and consider if you may ever want to return your car to how it was. For example: If a cop bugs you, regulations change, or a mechanic has a problem with it. It is an expensive piece just to hollow out. You can always cut it off and replace it with pipe. Thats what i did and i am glad i did it. After awhile the loudness got annoying and the exhaust gases tends to smell.

[Guest]

well, ya see, the whole purpose is to do "stealth mods" so far ive done pretty good..my parents have no clue its a well made street racing machine but...we will see.

[gar187er]

another thing though, even if your folks find out about it, or want you to replace it, get a  high flow one, only bout 60 bills, cheaper then a reg cat.....

why is everyone always worried about it being too loud, and ballsy...??!?!!? that just means youre car sounds great!!!!!  

[zach82]

I think removing my cat was the best thing I've done to mine so far.  I love how it sounds!  It's a very unique sound around home... all of my friends know its me before I even get to the door.  

[90BerettaGTZ]

be prepared to go thru a couple O2 sensors. if you burn one, unplug your battery and reconnect it, the computer will eventually learn to run without the cat in place. my calais did. it is a bit louder, but not too loud.

[Eway89GT]

project for this weekend!!!!!!!  BOOOYYYAAAHHH!

[Guest]

I wouldnt say that gutting your cat is a performance mod exactly. Sure it will sound better, any thing you do to increase air volume inside the pipe system will create a nice rumbling tone but it can actually cause airflow disturbance which can be detrimental to performance. If i were to do anything i would replace it with straight pipe,  after i opened up the whole system, at least after the manifold, or in my case since i live in heavily regulated southern california, buy a hi-flow cat, not the best thing for performance, but legal and better than gutting the cat.

When you gut out your cat you create a section of pipe that is several cubic inches larger than a section the same length in your regular system, this causes turbulence in your exuast system which slows overall airflow and creates more backpressure. a performance exuast system should be designed around proper scavenging, which is basically using sympathetic wavelengths in the exuast airflow to help evacuate exuast gas more quickly. in a proper system it is not just how much volume of gas you can flow, it is the velocity through the pipe that flows more gas and lowers backpressure. backpressure as we know is the enemy and if we lived in a performance perfect world we could just run short fat headers straight off the heads and live in a louder smoggier world. but since emissions controls are a way of life, exuast science is the way it is.

so my suggestion is given your parental situation, if you want a good rumble then by all means gut the sucker, but dont expect to see any performance gains off of it, especially if you are running stock exuast without larger diameter h/e.

if you want real gas pedal performance then look into a high flow cat, get one of the ones from summit for about 60 bills, i believe they are edelbrock, i could be mistaken though, and going at least .25-.5 inches larger at least from the cat-back, its not that hard to do, especially in a schools auto shop.

sorry for the rambling post, got carried away

[gar187er]

jeez a simple, high flow cat would been good enough...LMAO....point well put.....think of your exhaust system like an intake, you want it nice and smooth for air to flow....but not flow that easy

now i see why you were rambling on 95black2.2, late night last night huh!??!?! 2:30am!!!!!  

[rweatherford]

The cheaper high flow units in Summit Racing are Catco.

Rex (Has a cat, still performs well, and smells good too)

[RebelGT]

i forget which highflow cat we put on marks, but even still it smells a lil funky.