Quick question. I'm coming from VA with no emissions test. Is there any way either use catless XPipes or hi flow cats and pass inspections in NC? I keep hearing differing opinions on the matter. Any advice is greatly appreciated. I bought some off road xpipes before I knew I'd be moving and not sure if I want to either run with them part time, have hi flows welded into them or maybe just leave the stock cats in an install the xpipe behind them. Not sure if there would be any gains in the third scenario.

 

Sleeper_GT has an o/r x by JBA I believe that have pipes that replace the cats. They can be removed and the cats re-installed for emissions checks. But thats on a GT. Best bet is probably to have an exhaust shop install the O/R x and modify it so that you can configure it with the stock cats.
I have high flow cats in mine and I don't think it would pass the sniffer test, judging by the smells that come out of it. Also before the tune was modified it threw a CEL for cat efficiency below normal.

 

I don't have any experience with my Mustang, but my last car had headers and hi flow cats and I passed emissions fine.

 

You can pass with hi flow cats. They do not use a sniffer here, the cat inspection is visual. I do have the JBA O/R H Pipe. The down tubes can be pulled out with leaving the H Pipe in place and then put cats in. I'm going to try and find a place that will let me slide without making that change.

 

A lot of it depends on the tune too. When the cats are removed the rear O2 sensors are turned off usually. That won't trip a check engine light, but it WILL show up when they hook the car to the emissions machine as "rear O2 circuit incomplete" . I have heard there are ways around that with the tune, it just depends on who writes tune as to how they approach it. I found out the hard way a couple years ago when I failed inspection with a Lund tune. Ended up having to put the stock cats back on and loading the stock tune back in to pass.

 

With that, Lund told me he would write me a cat safe tune if need for testing. I would then just need a spare H-Pipe. HMMM

 

Dan told me with his tune I should be ok as long as I know someone that will let me by the visual part of it(which I do). Im hopeful, but not overly optimistic. We shall see next year I guess lol.

 

I typically run a Bama 93 race tune which turns off the rear sensors. Their street or performance tunes are supposed to be street legal. If I can do the spark plug fouler without causing a CEL then maybe it could pass?

 

It is a possibility, but I have heard mixed results with the anti-foulers. For some people they work, and for some they don't.

 

Nobody has posted up anything about using foulers on the new 5.0 or 3.7, so I suspect Ford finally decided to try and keep people from screwing with what they call "good enough performance".