AS&M single Cat conversion...
 

I'm gonna order my sometime in the next month. But i wanted to start ordering all the parts that i will need to do the job. My car is a dual cat car. I am converting it to a single cat car. So anybody that has done this before know all the parts i will need? Or a good site that i can get all of these parts? Also any other info that i should know when doing this will be appreciated thanks.

I want to go to the single cat style myself. Theonly problem I know of that you might want to look into is how to deal with smog. We both live in CA and the laws here are strict. sine you have a OBD2 setup with dual cats, I have heard that you cant move the location of either cat. If you know how to get by the smog or have already looked into it, then good luck to you. I know lots of people on this board have done it.

Well you wont be able to pass the visual part of the test. But you can find places that will pass you as long as you pass the emissions part of it.

I have AS&M headers. I use to have duel cats but changed it to a single cat. You just do the headers the same way you'd do any other headers. Then once you put on the y-pipe, go to a muffler shop and have them put on the highflow cat you want. You'll only be able to hook up the two front O2 sensors and for the back two, you'll just need 02 simms. Thats about it.

You will also need a single cat catback, or an spipe to connect your cat to your dual cat catback. Summit sells an Spipe if you call them, or get a custom one made.

Also,check this site out. Real cool guy if you have any questions.

www.go-fast.org/z28/headers.html

Thanks for the link Johnny. I'm gonna have to get the S-pipe since i already have the catback on. How long did it take for the install and what kind of header bolts did you use? I think i am gonna go with ARP bolts because i have heard that the stage 8 bolts can be a pita to deal with. Also what kind of gains did you get with them? Also how did the sound of the exhaust change. Again thanks for the replies guys.

I am almost finished with the dual cat to single cat conversion. I used mac headers. The only thing left for me is to have the S pipe and cat welded up. The installation is pretty straight forward. The only thing I though was tough was taking out the driverside cat. The flange on the end of the exhaust manifold is a little too big and you might have to take out the steering shaft, which is pretty easy considering you just have to unbolt 2 bolts. Also another recommended tip is to buy a can of PB Blaster. Its really good stuff. It help out in taking out bolts on the exhaust manifolds and also the y-pipe. Since your car is a OBD II you will need O2 sims for the back two o2s. Other than that I think thats pretty much it. If you have any questions you can e-mail me or send me a pm anytime. Good luck.

I noticed my torque was pushed back on the rpms. Somthing I didn't like. The thing is, I can get the wheels spinning alot faster now and sideways even more. You might see a change, but don't expect your car to become a monster. That'll happen after my cam install;)

The sound is great, two times louder now. It sounds more hollow. It's freaken loud with no plate in the Borla.

You'll love your AS&M's