Cats

[midwestLTD]

If I knock out the pelletts in my four cats ; then put them back on for a more free flowing system will this mess with the 02 ???It's on a 91CV..

[FordInPossession]

The rear O2's may read rich because of the direct exhaust, but as long as they are installed, it shouldn't trip the engine light.

[boXman]

He only has 2.

[gadget73]

No, it won't affect anything. Unless the cats are clogged, you're also not really going to gain anything either.

[88crwnvc]

i don't know if you'll like the sound, it will sound extremely poppy and making random popping noises.. if you have four cats, the back two are just resonators and are hallow already, air is pumped into the exhaust line right before them to create a hot burn and destroy carbon during the first couple of minutes while your car is running, after that, the air pump is useless pumping air into your exhaust because the front two cats are doing all the work.

if you just have two, and they are before the 02's, wouldn't hurt much, except for sound, but with the stock system it would probably be muffled enough to which you wouldn't notice it with the stock muffler.

[packman]

Awww c'mon, isn't that the point? A little bit more sound won't hurt anybody; and the popping, just find a hill, throw it in first and let off the gas, oh what fond memories.
Packman

[87mefull]

Its really a pain in the ass to gut the cats on panthers because of the bends in the pipe. I looked at it before and decided it wasn't worth it on my car. If you really want a free-flowing exhaust, it would be better to replace the cats with an off-road h-pipe, shorty headers, and 2.25 inch tails. If you think they are clogged, you can get a exhaust shop to check the back pressure for you. When they are clogged, you will have no mid-range to top-end power and maybe some blow-by.

[85crownHPP]

i.. if you have four cats, the back two are just resonators and are hallow already,

My rearmost cats definitly have the honeycomb catalyst in them....

[Blaze86Vic]

If your rear cats are empty, then your cats disintegrated a long time ago. All four are fully functional cats. Gutting them is not that hard, take that advice from someone who has actually done it and didn't run before even trying to. You will see an improvement in performance, simply because of the age of the cats. They will be clogged to some degree + older cats were not designed to flow as well as new ones are. A new set of cats will not hurt performance any measurable amount on a mild or stock engine. You exhaust will have a sort of tin can sound hint to it. Because of the odd flow patterns through an empty cat. It will be louder than stock by a very noticeable amount. With good mufflers it will not be too much though.

[midwestLTD]

Cats

Thanks will take all into consideration...I would like to have more of a Mustang sounding system.:megadeth:

[Blaze86Vic]

If you want that mustang sound, get rid of the cats all together.

[88Vic]

For the Mustang sound, go with Mustang shorties, catless h-pipe, and depending on what size exhaust you use, either 2.25" or 2.5" tails.