Up for a smog test and I have the following mods:

GST Tuned:
APS CAI
EQL header w/ integrated up pipe
Grimmspeed boost controller
Cobb downpipe w/ high flow cat
STi CBE

Though my car has been backfireing a bit during daily drive... not sure what could be causing that, didn't used to even a few months after I got the tune.

I just went in for a test today and failed with the following:

Idle - 2500 RPM
HC 228 - 2.46
CO 99 - 2.11

I assume something is really wrong ;-)

 

^ i passed with more mods then you but stock downpipe

 

stock downpipe back on and your solid

 

Hiflow catted dp doesn't guarantee passing smog tests...

Swap a stock dp and you should pass

 

Thanks for the replies! Would I need to flash back the stock map?

 

Nope, just drive easy on it until you get the stock DP off. If your car is back firing its most likely running rich from having a boost leak, pressure test your system and fix any leaks.

 

What? You don't need to tune back to stock map to smog?

 

^ no, a tune if anything makes the car run better

 

Weak... I had a stage 2 open source tune and someone told
Me I needed to get the stock map back...

 

yeah sometimes a tune will make the car run way cleaner. ed has told me just swap dps and youre good to go. just dont leave it on long and try not to hit boost. wanna keep the cats nice and clean.

 

I had the same exact numbers trying to pass without a cat at all, maybe just a little higher HC at idle. Put the stock cat on and nearly 0's! Still with a tune also. The smog guy was in awe.

 

thanks for the info guys... gonna be smogging the car today... everything should go well today...

 

If my car was modded, and if it hypothetically had a nice fat "stage 2" ECUtek tune (catless TBE, CAI, Walbro) with a bunch of registers turned down, and if I hypothetically bolted a stock DP back on for a few hours for smog, it would have hypothetically passed with numbers better suited to a Prius tailpipe, on said hypothetical tune. No shens or hookups involved, no muss, no fuss.

Hypothetically, of course.

 

I may or may not have passed smog with a lot more than that, other than a high-flow catted dp on my tbe, and got 0s for most of my numbers.

Of course the stock dp would clean better than an aftermarket cat. As long as your hypothetical tune is a good tune, and your stock dp cat is warm, you should have no problem.

Aftermarket tunes are usually leaner and produce a more thorough burn of the combustion chamber which reduces the number of hydrocarbons, reducing emissions.

 

Thanks for all the great info guys! I'll be swapping the dp and giving it another go later today. I'll update with results!