How do smog checks work?

hokiedood · 10-27-2019, 03:29 AM

I'd like to upgrade my downpipes to a high flow catted version. Am I safe to pass smog checks if the downpipes don't cause a CEL? What exactly do smog check stations look for in OBDII checks?

Craven_01 · 10-27-2019, 01:11 PM

You won't pass visual inspection.

hokiedood · 10-27-2019, 06:58 PM

Quote:

Originally Posted by Craven_01

You won't pass visual inspection.

How would they see the downpipes without lifting the car?

esoj37 · 10-27-2019, 07:01 PM

Quote:

Originally Posted by hokiedood

How would they see the downpipes without lifting the car?

They use mirrors in NJ, dunno about CA.

Craven_01 · 10-27-2019, 10:00 PM

They use mirrors in CA too.

hokiedood · 10-31-2019, 01:11 AM

How are CA people getting away with having aftermarket downpipes?

Snoopy8 · 10-31-2019, 01:36 AM

Quote:

Originally Posted by hokiedood

How are CA people getting away with having aftermarket downpipes?

Put the stock downpipe/cat every 2 years or when smog is due. That's the main reason I didn't go through with that mod

bimmer456 · 10-31-2019, 07:47 AM

I only saw them hook up a device to odb port didn't even run the engine. Don't recall seeing them use any mirrors and no tailpipe measuring device. Of course it was a Camry so they wouldn't think I'd have a cat delete. And didn't sound louder or different when I pulled in. It would seem odd that they would use mirrors though just to do smog check. Why not just drive it on ramps and look underneath. If you have under body panels you would need to remove those.

Jeef · 10-31-2019, 09:39 AM

Your race cat will eventually not pass smog either. Might as well go catless and pay to play as needed.

Gen13 F36 · 10-31-2019, 10:56 AM

Quote:

Originally Posted by hokiedood

How are CA people getting away with having aftermarket downpipes?

Secret....need an inside man...bro

I got away with JDM motor swap

10-27-2019, 03:29 AM	#1
hokiedood Private First Class 31 Rep 150 Posts Drives: 2016 BMW 340i Join Date: Feb 2019 Location: San Francisco iTrader: (0) Garage List 2016 BMW 340i [0.00]	How do smog checks work? I'd like to upgrade my downpipes to a high flow catted version. Am I safe to pass smog checks if the downpipes don't cause a CEL? What exactly do smog check stations look for in OBDII checks?
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10-27-2019, 01:11 PM	#2
Craven_01 Private First Class 12 Rep 129 Posts Drives: 2013 F30 Join Date: Oct 2016 Location: SoCal iTrader: (1)	You won't pass visual inspection.
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10-27-2019, 10:00 PM	#5
Craven_01 Private First Class 12 Rep 129 Posts Drives: 2013 F30 Join Date: Oct 2016 Location: SoCal iTrader: (1)	They use mirrors in CA too.
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10-31-2019, 01:11 AM	#6
hokiedood Private First Class 31 Rep 150 Posts Drives: 2016 BMW 340i Join Date: Feb 2019 Location: San Francisco iTrader: (0) Garage List 2016 BMW 340i [0.00]	How are CA people getting away with having aftermarket downpipes?
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10-31-2019, 07:47 AM	#8
bimmer456 Major General 2950 Rep 5,984 Posts Drives: 340i Join Date: Nov 2016 Location: Pasadena, CA iTrader: (0)	I only saw them hook up a device to odb port didn't even run the engine. Don't recall seeing them use any mirrors and no tailpipe measuring device. Of course it was a Camry so they wouldn't think I'd have a cat delete. And didn't sound louder or different when I pulled in. It would seem odd that they would use mirrors though just to do smog check. Why not just drive it on ramps and look underneath. If you have under body panels you would need to remove those.
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10-31-2019, 09:39 AM	#9
Jeef Lieutenant Colonel 388 Rep 1,945 Posts Drives: AW E92 335i Join Date: Nov 2008 Location: San Diego, CA iTrader: (6)	Your race cat will eventually not pass smog either. Might as well go catless and pay to play as needed.
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