concerning uppipes, it depends how strict the place is with the visual. on my wrx, i threw in the stock downpipe, and left the aftermarket uncatted uppipe and cb. it passed the sniffer, but the guy refused to pass it completely because the computer told him that the car has 3 cats and he couldn't find the third.

drove to a "high volume" place down a few blocks down and passed with no issues.

 

Stock downpipe = pass sniffer

For smog shop that is only concerned about sniffer - PM me

Easy.

 

just wanted to add to this thread.

indeed, "stock downpipe = pass sniffer"

i just passed smog today with the stock downpipe back on, even with a stage 2 OTS Cobb tune! i did not reflash back to stock.

interesting note: even with the cobb catted downpipe installed, it did not pass. was showing about 140 ppm HC for the 2500 rpm test. max is 130 ppm for 2500 rpm test so it just barely went over the max figure. with the stock downpipe back on, passed with flying colors! from 140 ppm HC to 5 ppm HC. so if you guys need to pass smog legally (! lol) put the stock downpipe back on! now the real question is, should i sell my cobb downpipe since it wont pass smog anyways? lol

just noticed that code3suby passed with the cobb catted downpipe. wonder why his passed but mines didnt. guess it depends on the car. wish mines passed with the cobb downpipe!

 

aftermarket downpipe....I doubt it but I've heard one dude passed the smog check, here in Sac, with the catless downpipe...
I passed twice with stage 2, catback exhaust and even BOV....had stock downpipe

 

He was probably running corn oil. Lucky SOBs.

I swear, as soon as one E85 station opens up down, I'll be on it in a second.

 

I was checking some things on the smog machine at work. My car would pass (barely) with the stock catted uppipe and a catless downpipe on a stock tune.

 

What if you use the Cobb fuel economy map that makes your car run a bit lean? Would that help your chances of passing?