modified c6 state emissions
Thread Starter
Pro
Joined: Jun 2015
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Likes: 110
modified c6 state emissions
What are you guys doing about state inspections and emissions testing on your street cars with cams,headers,head work,tuners,etc?
The state of conn wants to see the cats and inspects for pass codes. That would mean swapping everything back every 2 years.
I don't want to turn my c6 into a trailer queen but would like more power.
The state of conn wants to see the cats and inspects for pass codes. That would mean swapping everything back every 2 years.
I don't want to turn my c6 into a trailer queen but would like more power.
Le Mans Master
Joined: Nov 2007
Posts: 6,415
Likes: 198
From: Wilkes-Barre Pa
What are you guys doing about state inspections and emissions testing on your street cars with cams,headers,head work,tuners,etc?
The state of conn wants to see the cats and inspects for pass codes. That would mean swapping everything back every 2 years.
I don't want to turn my c6 into a trailer queen but would like more power.
The state of conn wants to see the cats and inspects for pass codes. That would mean swapping everything back every 2 years.
I don't want to turn my c6 into a trailer queen but would like more power.
Drifting
Joined: Nov 2013
Posts: 1,525
Likes: 495
From: Southern California
Some mild cams and heads will pass the emissions test although changing the cam, heads and doing a tune might be a violation, I doubt anyone would spot it if the exhaust is clean. Headers and moved or removed cats are a red flag issue and can cost big bucks if spotted by the wrong (right?) folks. Some states are more strict than others. Headers and no cats is asking for trouble here in California. You have the same standards as California but I have no idea how strictly your laws are enforced.
Last edited by Guard Dad; Aug 20, 2015 at 03:11 PM.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
What are you guys doing about state inspections and emissions testing on your street cars with cams,headers,head work,tuners,etc?
The state of conn wants to see the cats and inspects for pass codes. That would mean swapping everything back every 2 years.
I don't want to turn my c6 into a trailer queen but would like more power.
The state of conn wants to see the cats and inspects for pass codes. That would mean swapping everything back every 2 years.
I don't want to turn my c6 into a trailer queen but would like more power.
Does that mean visually see the physical cats, see computer printouts of probed tailpipe emissions, or just see that no engine codes exist through the OBDII port?
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
I would suspect most states have similar requirements.
When they plug into the OBD port they are typically checking for emissions readiness checks. The inspection equipment relies on the cars computers answers on whether it believes all emissions related items are working as expected. Some states allow up to one system to be "not ready" and still allow you to pass.
It's important to note that engine codes and emissions readiness checks are two totally (although somewhat related of course) things. I'd guess the emissions equipment looks for codes as well.
Basically the computer runs through a series of checks to make sure all the emissions equipment is working correctly. i.e. pre cat O2's and post cat O2's are responding as expected (post cat O2's will cycle differently than the pre cat ones if the cats are working properly). It checks that the EVAP system is sealed properly, etc.
There is a way in HP Tuners to make the ECM basically not check any of these things and go straight to "all emissions checks are good", which will have no problem passing an inspection when they plug into the OBD port.
Here's a good explanation of one of the checks, for anyone curious. Credit to Greg Banish / Injector Dynamics
http://injectordynamics.com/articles/shelby-gt500/
6/9/2012:
Catalyst monitor diagnostic operation explained in 3 minutes by Greg Banish of Calibrated Success.
In order to explain this best, we need to look at raw O2 voltage signals both before and after the catalyst. The front O2s should be switching pretty rapidly as we toggle around stoichiometric mixture at idle and cruise. The downstream O2 signal should be much smoother. This is because a working catalyst is actually a sponge for oxygen, damping the release rate of oxygen to the downstream exhaust and O2 sensor. There will still be switching of the rear O2 sensor, but at a frequency that is much lower than that of the front.
The Catalyst diagnostic is looking at the ratio of front switches versus rear switches (or vice-versa, depending on how they wrote the code) and coming up with some ratio. If this ratio is 1:1, then the rear O2 is moving exactly as the front and the catalyst isn’t doing anything: FAILED TEST! If the rear O2 is switching, but at a frequency much less than the front, the catalyst must be acting like the proper O2 sponge that it’s designed to be: PASSED TEST! Somewhere in the three-year development process for that engine and vehicle calibration, the closed loop diagnostic calibrator came up with the right value for this switching ratio that matches “good” emissions and properly lights the MIL in the event of a non-working catalyst and “bad” emissions.
So what does this mean when you’re getting the magical scan for the DMV? They just have to plug into the OBDII port and query the test history to find out whether your catalyst is leading to the right switching ratio between upstream and downstream sensors and they can determine the health of your catalyst without ever even putting the car on a hoist or emission sampler. The OBDII diagnostics are already keeping track of that for them.
In order to explain this best, we need to look at raw O2 voltage signals both before and after the catalyst. The front O2s should be switching pretty rapidly as we toggle around stoichiometric mixture at idle and cruise. The downstream O2 signal should be much smoother. This is because a working catalyst is actually a sponge for oxygen, damping the release rate of oxygen to the downstream exhaust and O2 sensor. There will still be switching of the rear O2 sensor, but at a frequency that is much lower than that of the front.
The Catalyst diagnostic is looking at the ratio of front switches versus rear switches (or vice-versa, depending on how they wrote the code) and coming up with some ratio. If this ratio is 1:1, then the rear O2 is moving exactly as the front and the catalyst isn’t doing anything: FAILED TEST! If the rear O2 is switching, but at a frequency much less than the front, the catalyst must be acting like the proper O2 sponge that it’s designed to be: PASSED TEST! Somewhere in the three-year development process for that engine and vehicle calibration, the closed loop diagnostic calibrator came up with the right value for this switching ratio that matches “good” emissions and properly lights the MIL in the event of a non-working catalyst and “bad” emissions.
So what does this mean when you’re getting the magical scan for the DMV? They just have to plug into the OBDII port and query the test history to find out whether your catalyst is leading to the right switching ratio between upstream and downstream sensors and they can determine the health of your catalyst without ever even putting the car on a hoist or emission sampler. The OBDII diagnostics are already keeping track of that for them.
Last edited by schpenxel; Aug 19, 2015 at 08:51 PM.
Safety Car
Joined: Nov 2007
Posts: 4,433
Likes: 873
From: Bay Area CA
I'd be curious to know what is required there too. In my state they require to visually see that catalytic converters are installed. I ASSUME they want you to have the factory original cats, but I do not know that as fact.
I would suspect most states have similar requirements.
When they plug into the OBD port they are typically checking for emissions readiness checks. The inspection equipment relies on the cars computers answers on whether it believes all emissions related items are working as expected. Some states allow up to one system to be "not ready" and still allow you to pass.
It's important to note that engine codes and emissions readiness checks are two totally (although somewhat related of course) things. I'd guess the emissions equipment looks for codes as well.
Basically the computer runs through a series of checks to make sure all the emissions equipment is working correctly. i.e. pre cat O2's and post cat O2's are responding as expected (post cat O2's will cycle differently than the pre cat ones if the cats are working properly). It checks that the EVAP system is sealed properly, etc.
There is a way in HP Tuners to make the ECM basically not check any of these things and go straight to "all emissions checks are good", which will have no problem passing an inspection when they plug into the OBD port.
Here's a good explanation of one of the checks, for anyone curious. Credit to Greg Banish / Injector Dynamics
http://injectordynamics.com/articles/shelby-gt500/
6/9/2012:
I would suspect most states have similar requirements.
When they plug into the OBD port they are typically checking for emissions readiness checks. The inspection equipment relies on the cars computers answers on whether it believes all emissions related items are working as expected. Some states allow up to one system to be "not ready" and still allow you to pass.
It's important to note that engine codes and emissions readiness checks are two totally (although somewhat related of course) things. I'd guess the emissions equipment looks for codes as well.
Basically the computer runs through a series of checks to make sure all the emissions equipment is working correctly. i.e. pre cat O2's and post cat O2's are responding as expected (post cat O2's will cycle differently than the pre cat ones if the cats are working properly). It checks that the EVAP system is sealed properly, etc.
There is a way in HP Tuners to make the ECM basically not check any of these things and go straight to "all emissions checks are good", which will have no problem passing an inspection when they plug into the OBD port.
Here's a good explanation of one of the checks, for anyone curious. Credit to Greg Banish / Injector Dynamics
http://injectordynamics.com/articles/shelby-gt500/
6/9/2012:
Yes, all the above. Same here in CA, Emissions testing checks for readiness codes using the OBD for proper function. In CA, we are allowed to have one code incomplete. Also, visual inspection of PCV valves correctly routed and exhaust system with catalytic converters in proper locations.I have an A&A supercharger kit that is CARB certified and passed smog here in CA. The smog ****'s measured my S/C pulley, HB, check the PCV routing and entire exhaust system. I had one readiness code incomplete and passed with no problem.
Another smog **** emissions station used a mirror with a long handle to check my Chevy Silverado work truck all stock. It looked like I was at a check point in Afghanistan checking for IED's.
Last edited by Mike's LS3; Aug 20, 2015 at 10:42 AM.
Thread Starter
Pro
Joined: Jun 2015
Posts: 627
Likes: 110
Yes they do a visual on the cats but they plug into the obd port and it must have no codes stored or active in memory. That info is transferred to the state from the privately owned inspection station.
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Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
In the tune, as already noted previously, is the capability to bypass OBDII code output. So that means headers with cats, don't need a tune change, or the alternative is gut the cats and change the tune, because either way they need to visually exist. Another route is using catted headers that have an available cat delete off-road pipe that can be swapped in and out. The third choice would be checking the requirements in neighboring states and changing mailing addresses and auto registrations.
