Smog Q? Maybe for bdcardinal?

[MT1083]

I've never been given a good answer on this but why won't (in most cases) a catted x or h pass the sniffer test? I have a Bassani catted x that had won't pass inspection when I have to go next. The only time it passed last time was because of a buddy at the shop. It makes my car run a bit richer than when stock and was just wondering what causes this besides non-OE cats? Just is just have to due with the size of the pipes, placement of the h or x? I would like to know if there is anything I could change, besides going back to my stocker for a day, like buying different cats, that would allow me to pass.

 

[MT1083]

Ttt

 

[jstreet0204]

If everything else is functioning right, a different x pipe will not make your car run rich. Also here in Winston Salem, they no longer use a sniffer test for obdII cars. Just the obdII test, so if you aren't throwing any codes, you should pass.

 

[Shiroelex]

It's because the cats are further downstream. Something to do with the exhaust cooling off too soon; before it goes through the cats. The O2 sensors only have so much of a range they can allow before having to throw the MIL, which in turn will adjust the car's air/fuel ratio. There's a much more technical explanation of it all out there somewhere; I just know that one of the reasons was because of the cats being further down the system. Another reason was some of the catted midpipes come with high-flow cats, which sometimes flow too much. Or, there's the one I saw where the 'high-flow' cats turned out to simply be little baby glasspacks.