I have a 99 Maxima that is Cali Spec. Looking at the front exhaust header there is a pre-cat in the header. Was wondering if anyone has replaced this with a high flow cat version?

I have searched and seen people putting a fed spec header on, and installing an o2 sim. But no one installing a high flow cat. Also have considered gutting it, but dont want problems there.

Any info would be appreciated

 

If you take the front precat off the front manifold you'll notice that the hole feeding the precat is small less than 2" in diamater. Also i don't know if there is a high flow front pre cat available for the maxima. You're better off doing a fed spec conversion. Cheaper too.

 

No such thing. Do a fed spec conversion (quit a bit involved), or start from scratch and get Cattman headers or the like (very involved).

 

Figured as much. Sucks though. Stupid California emissions.

When you say quite a bit involved, is it just mainly trying to get the front o2's to not throw an engine light?

Would be interested in doing it, but I don't want to gain like 5 hp from all the work. lol