I Have A Question About My Cat.... If I Have Gutted The Two Precats Do I Need To Remove The Third Main Cat? I Believe It Is Cloged How Would I Tell. I Think I Am Loosing Power Also... If I Get Rid Of My Main Cat Too Will My 5th And 6th Ports Have Trouble Oppening?
I Appreciate All Your Comments You Havef Been So Helpfull For Me.

 

Well you don't need to remove it, but if it is clogged you might as well. Take it off and look through it with a flashlight. You will see a honeycomb looking material and it should be intact. It shouldn't be breaking into pieces, like mine was doing. If it looks good just keep it and have an exhaust shop weld up a cat replacement pipe with two flanges to hook up to the stock system. I got one made for $20 at Midas. If you just gut it the sound will be strange, I personally didn't like it, but if you cat is crap you might want to try it. If you have an S4 86-88 FC then you will need to either run an electric 5/6th port conversion or have the exhaust shop weld a bung and a pipe to connect to the split air pipe.

 

I don't mean to rob this thread, but I'm also curious on cats. I've got the RB header and pre-silencer and I really don't want to have to take all that off again to put the rotting old stock cats back on it. If I got a large cat to replace the pre-silencer would that be sufficient to pass the smog test? Or would i have to spend a lot of money to get a brand name Bonez cat? I'm just looking for the cheapest solution.

 

Most aftermarket cats will burn out due to the rotary's high heat output.

 

Buy a high flow cat. I removed my cat and the fumes that were coming from my car were rediculous. A high flow cat is better for everyone and its safe for the environment...

 

No cat = Spitting flames. An RX-7 that doesn't spit flames... just isn't right.

 

I have the RB collected header and a Bonez hi-flow cat. I can definitely tell a difference from the original cat setup to what I have now. It now smells more catalyzed.

 

hollowing out the cats is a bad thing to do, it makes alot more turbulance in the exuahust and probably hurts you more than help you. you can buy cat replacement pipes from racingbeat for 300 and probably cheeper other places.

 

bonez is good. they're made for rotaries and it has a nice sound to it. RB makes good hi-flow cats too. i wouldnt settle for anything other than those two

 

Corksport downpipe and midpipe, like jigsaw said, it's all about the flames.

 

that settles it, thank you all for your help my white baby will be shooting flames here in the next month!!!!