Will a free flow cat increase me hp alot? or will eat eat up my header?

 

I dont know how it's going to eat up your header...

my cat to the krapp on me so i gutt it...I can feel the difference without the restriction

 

Some people claim the stock cat poses a restriction simply because of its size, some people claim the stuff inside the stock cat slows down the flow. What I believe is that the stock cat acts kind of like a sponge. At first it flows pretty freely but after it soaks up a lot of smog particles it gets gunked up and slows things down. Replacing an old gunked up cat with a brand new OEM one would gain a bunch of power because the old one would be such a restriction.

I wouldn't say to gut your cat as a permanent solution, that's about the same deal as running a test pipe. You won't pass emissions for one thing, and it makes your car stink. Nothing like unburnt hydrocarbons to wake you up on the morning drive to work....

If your car has a lot of mileage on it and the original stock cat, a high-flow piece is a good idea. If your car is relatively new I wouldn't worry about it yet.

 

No emissions in FL wahoooooooo

 

A lot of aftermarket hi-flo cats get "eaten up" and end up needing to be replaced, but it has nothing to do with the header.

I would recommend a carsound hi-flo cat; unless you don't mind running a test pipe 24/7. Gutting your stock cat (unless it's wrecked and rattling) isn't really the best way to go about things.

Overall, a hi-flo cat coupled with I/H/E works as part of a system and will net you some pretty good gains. (I've seen 10-20 whp on a stock B18c1)

Shingo

 

If you know a good exhaust shop, you can also have a replacement pipe flanged to take the place of your cat. Then when it is time to go get your car smogged, just bolt your stock cat back in. That’s what I do and it fits between my header and catback exhaust perfect.

 

So any muffler shop can make me a "test pipe"? How much do they run for? And i guess they will have to make somethin special for my o2 sensor?

 

Well if you are replaceing just the cat and leaving the rest of your exaust, yes any muffler shop can do it. And you don't have to worry about your o2 sensor. now if you want a test pipe race dump, you might want to check with your header manufacturer and see if they make one. I do now JG/Edelbrock makes a racing B pipe that has a spot for your o2 sensor but it only works with the JG/Edelbrock header.