Downpipe California and SMOG

Seal

Seal

Silver Member
My 2011 came with a K&N air intake and Cobb cat back exhaust. I was able to pass smog but as I get into mods like changing my HPFP internals I’m thinking of changing the downpipe but I wanted to know:

A. Do all aftermarket down pipes that can increase HP come at making the vehicle unable to pass smog in California?

B. If not, what downpipes are my options to choose from?

C. As an extension question: what mods can I do to increase HP that don’t affect SMOG testing/ for those in CA that do have components that will not pass SMOG: what do you do? Swap the parts out before the required SMOG testing?

Thanks
 
You need a CARB sticker on any mods in CA. I don’t remember ever seeing a down pipe that had one. Maybe the (larger diameter) corksport or Cobb intakes had them?

Your best bang for buck mods are going to be rear motor mount, then e-30 tune. Rear sway bar as well, not for ooomph but general fun driving.
 
Easter Bunny said:
Hofp
Corksport intake
Corksport tmic
Gut 2nd cat
E30 tune

That's about all you can get away with in California
Click to expand...

If I changed the downpipe and got an E30 tune, could I swap back the OEM downpipe when it came time to SMOG and be able to pass or would I have to have the car retuned to account for the OEM downpipe to be able to smog it?
 
You would probably need different tunes, but you could have them both saved and just switch as necessary.

That said you don't want to be swapping back and forth every to years it's kinda a royal pain in the dick to swap

If you want to max power you could swap the turbo to a bnr s3 since it will look pretty much stock with all the heat shields in place

Do they look for retuned ECUs in California when you smog?
 
Yeah, it would be a total pain swapping out the downpipe.

There is a V1 S3 BNR for sale near me. The different versions matter?
 
The version isn't going to matter as much as the condition. You will need a tune to run it though.
 
If you go to a larger intake your car likely wont start / run well.

Edit: dont know about downpipe at idle. Def not happy with throttle though. Does reflash erase runtime info used for smog?
 
Reflash does reset readiness monitors. You would need to drive the car some distance to get all the monitors into a ready state
 
I think I’ll pass on the downpipe. Does a new turbo inlet pipe affect the smogability?

I got a used Corksport TMIC but have not installed it yet. Still looking for an Access Port and I have to change my HPFP internals and may get the new Orings for it in case I do e30.
 
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