Contour Enthusiasts Group Archives Forums Modifications Duratec Performance REMOVE CATS (NOT SECD.) OR NOT TO DO IT...........

i am thinking of doing it the next couple days but if it wont help me out then i aint going to do it.. but i was going to remove the main cat i guess but not the secondary cat (keeping that one)... so should i do it on a SVT or not?

the main cat vs. secondary?
let me ask you this, is the cat or cats you're going to remove on the exhaust manifold? If so, that's what we call the light-up cats, or pre-cats. If you're planning on gutting those, yes, they will net you some good hp gains.
The main cat is the cat right behind the ypipe and near the flex joint. If you're planning on gutting it, DO NOT. If you're planning on putting a straight piece of pipe in place of the cat, that should work well.
Hope that helps.

so what cat should i gut? like should i gut the pre-cat? or the light up cat? or are those the same thing?

Originally posted by CEG18:

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so what cat should i gut? like should i gut the pre-cat? or the light up cat? or are those the same thing?

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dont gut the main cat. the "light up" cats and precats are the same thing. if your going to gut something, gut the precats.

precats (2 of them, one on each cylinder bank) = ok to gut (exhaust velocity increases)
main cat = not ok to gut. exhaust velocity slows down.
if you want to replace your main cat w a straight piece of pipe, that's good for some power.

so gut the 2 cats for each cylinder bank? like does it bolt on?(the cats) or weld on? and is it also easy to take it off if its bolt on? I am so confused but i think i get it.. there are two cats up front and those are okay to gut and the one in the back (kinda) is not okay...

the precats are part of the manifolds..you have to remove the manifolds from the heads to gut them....the precats aren't seperate from the manifolds...

The Cats on the Manifold are the Primary Cats, and the one down stream of the Y is the secondary.
As I read from my Factory Service Manuals.
Primary they do most of the work thus why the sensors are around them and not the Secondary under the car..
Of course this is my Theory based on the facts I've read..

Now some people not sure who, have gutted their cats and still pass the ole' sniffer test.

If you gut your pre cats. Make sure your state or province does their emmision testing on a warmed up vehicle. As I understand it the greatest effect of the pre cats is on the enitial start/warm up period. Otherwise their need deminishes once the vehicle is up to operating temps.

i have a set of manifolds already gutted for sale.....300 plus shipping if you want them


send me an email if interested i dont check the board often
corey_pimp1@yahoo.com