alright guys. this is more of an extension from my last thread. I'm getting 2 maggy high flows in place of the four stockers on my 98 expy tommorrow. what i need to know is whether or not this set up will pass the emisions test in TN. I live in the memphis city limits so they still stick the sniffer up your tail pipe.

Thanks!

 

Stock exhaust manifolds? I put on LT headers and a pair of 94106 magnaflow cats in place of the 4 stock and could not pass CO emissions. My cats were 1 yr old when testing was done

 

yep. they're stock manifolds. does that make a difference? i'm thinking about throwing in some "guaranteed to pass" additive in the gas tank when the time comes.

 

how did you pass emissions in co once you failed?

 

I had new cats (were not ''high flow'') installed. I think the Magnaflow were around 400 cells per inch, these were around 700-750 cells per inch. Only was failing on NOx (even after cleaning out throttle body and replacing IAC and EGR components).

 

I would drive it for 30 minutes at highway speeds and then pull it in for the sniff test before it cools down. Better yet, wait to pass sniff test before replacing cats and that will give you at least a year before you have to worry about it.

 

don't even waste your effort with that wonder-crap-in-a-can

 

Take it for a good beating before you go, get it nice and hot. I've heard running a tank of higher octane helps, fuel injector cleaner too!