Two Cat setup?? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Dream240 · 12-15-2003, 01:46 PM

I've been doing some thinking on how to keep my car smog legal when it goes turbo now that I'm back in CA. I don't want to remove my exhaust or have to change the setup everytime I have to smog it.
I'm running with a Hotshot header, Random Tech. high-flow cat, and Apexi N1 dual. here's what I'm thinking:
I want to run the turbo setup with a T04 manifold and a 3"down pipe, but with 2 high flow cats back-to-back then the exhaust, thus making the downpipe a custom shorter piece.
1. Has anyone ever done this?
2. Would it help the car to pass smog?
3. How much would the setup increase back pressure?
4. Would this setup be ideal for my needs or just run the OEM cat setup along with the high flow cat?

Any info would be of help.

12-15-2003, 01:46 PM	#1
Dream240 Nissanaholic! Join Date: Dec 2002 Location: Inland Empire, California Age: 46 Posts: 2,188 Trader Rating: (8) Feedback Score: 8 reviews	Two Cat setup?? I've been doing some thinking on how to keep my car smog legal when it goes turbo now that I'm back in CA. I don't want to remove my exhaust or have to change the setup everytime I have to smog it. I'm running with a Hotshot header, Random Tech. high-flow cat, and Apexi N1 dual. here's what I'm thinking: I want to run the turbo setup with a T04 manifold and a 3"down pipe, but with 2 high flow cats back-to-back then the exhaust, thus making the downpipe a custom shorter piece. 1. Has anyone ever done this? 2. Would it help the car to pass smog? 3. How much would the setup increase back pressure? 4. Would this setup be ideal for my needs or just run the OEM cat setup along with the high flow cat? Any info would be of help. __________________ Don't mess with my monkey...he's loaded.