I undertaking getting the main cat off.. took 45 minutes to get one bolt loose, took wd40 and a torch to heat it up. WHAT A BITCH, im going to GUT this bitch, What diffrence in SOUND and also preformance will i mostlikely Incounter? Stock everything!!!

Noticed three cats, is this correct?? one main, two small... and should i bang these out too. or leave them alone??

88 GXL

 

I can tell you for certainty that no cats gives a slightly louder, deeper sound to your exhaust. Some performance gains can be seen, depending on the condition of you catback.

When I had stock exhaust and no cats, no big difference. I put my Dynomax catback in and a 2.5" pipe to replace all the cats, now it sounds deep.

 

u got a 88
just take them all out and get the air pump off as well
it might be loudER, but it'll be mAd qUiK y000 !!one!2211!!!

 

I am running a strait pipe in place of all the CATS with a custom downpipe, stock y pipe and mufflers. Those 2 other smaller CATS are mainly just silencers but you should remove them as well if you want a free flowing system. Even with stock mufflers my setup is definately louder, but not too loud. Its still quieter then most of the ricers. If you want to hear loud take off the mufflers and go for a run w/ strait pipes. I think I scared the **** out of a corvette driver that I passed lol.

 

the main cat stays hot For like over an hour. I jacked it up and let the car cool for while. Went back the exhaust was cool in all parts Exept the main cat! it was still warm. allmost hot, But i never get any exhuast warning or anything, Im thinking the cat is full of somthing that keeps heat in for a long time. not sure what to do with the other cats, i should just geet a whole new pipe system

 

Which models of our cars came with all 3 cats? Does it go by the year of the car it is or just turbo & n/a?

 

Get a pipe made up to replace the cats. It'll flow a helluva lot better than gutted cats, which cause very turbulent flow.

 

I recently gutted the cat on my 89 and it got a little louder and ran better. It has a bit more of a metallic sound, and it doesn't sound as deep as it used to. I personally like a deeper sound but I'll live with it since it improved performance.

I streetported this engine when I rebuilt it so I'm not sure how much of a power difference if would make on a stock motor. Probably noticeable in any case if it was getting plugged up.

Also it will stink a little more, I notice it sometimes when I'm sitting at a light. It's a strange smell, not sure how to describe it. If I ever upgrade the exhaust on this car I'd consider putting a bonez superflow cat on to hopefully take care of the smell.

 

I love that smell, smells like a dirtbike or somthing.

 

YUP. it sure does Smell. your right about that. cant explain it, very sweet smell. . BTW got slightly louder hardly notice the diffrence

 

BTW gutting this thing was not as easy as it sounded. took like an hour, or more.

 

Dont ghetto gut the cats lol. Just put a pipe there to replace them, its not expencive and its ALOT easier lol.

 

The s4 cars (86-88) came with 2 pre-cats (the smaller ones) and one main. The s5's came with just one pre-cat and the main. The pre-cats basically help emmisions when the car first starts, but don't do much once it warms up.

 

To late I ghetto gutted mine a few weeks ago. Its a temp thing till I get a pipe made for it. Side effects: Loud, (Weed Eater on steroids), Backfires, Shoots nice flames. Other than that its ok. I hope going to a strait pipe cures some of the backfire.

 

I have an 89 (s5), it did have the 2 pre-cats and one main cat. Did 89 na have the same exhaust as the s4's?

 

lol yeah, whats your a/f ratio lookin like?
whats your mods?

 

EDIT--- oops, i double posted lol

 

nothing major at the moment. Custom CAI, Ghetto Gutted Cats....Body kit ordered, if it ever friggin gets here. Going to shoot the car as soon as the weather gets better. Thinking about this dark BMW grey.

 

i was going to say that the turbulence won't yield as much HP gains as a FREE-FLOWing exhaust........don't gut them, keep them for a rainy day....trust me on this.

S4s had 3 cats.....S5s had 2....IIRC

 

I have a s5 (1989) and the stock exhaust had three cats, two pre-cats and one main cat. Whats up with that?

 

i have an 88 gtu with strait pipes all the way back but its not all that loud my moms corsica is louder and it has mufflers on it

 

Nope, NA's have three cats, Turbos have two. S4 and S5 are the same in this regard.

 

did you gut the pre cats too? i just gutted the main im thinking of going back in,! When i gutted the main i hardlyh Noticed any sounds diffrence. I dont get it

 

ahh, your car a N/A?

If you going to gut a cat (if not all of them) atleast gut the precat (or so it right and get a down pipe LOL. The precat is cause pretty high "under the hood temps" (specially in the turbo II's, I aint as sure about ti with the N/A's). With a turbo II or a FD, the first thing I would do would probably be to get a downpipe.

 

the pre cats cause high under hood temps? what do you mean