Hello all,
I have a 2015 V8V 6M here in Denver, Colorado that is due for emissions testing / registration renewal. After I purchased the car I installed the Velocity headers, 100 cell race cats (came with the system I purchased, replacing the secondary deletes on the car), an x-pipe and velocity back box. Between crap weather and catching the crud I haven't had the opportunity to take it to a testing station, and before I do wanted to ask what folks' experiences have been with emissions testing on a modified system. Especially here in Colorado. Any input is appreciated.
Thanks,
Erin

 

I don't have direct experience with CO. I used to live in Conifer, but a long time ago now. What I do know, is CO has adopted the same ECU testing as CA introduced in July 2021. The ECU test is looking for a CVN that comes from the factory to identify factory data tables. If the car is tuned with an aftermarket tune the CVN will not match and both CO and CA now fail the test based on that. Some aftermarket tuners are getting their products CARB certified and if so, then it will pass.

CA also does a visual inspection and will reject any car with headers, and other modified emissions devices such as intakes, etc. I don't know if CO does that, but probably does.

 

I don't have any experience with testing on a modified system, but the last time I took mine in (2009 V8V Roadster) they only connected to the OBD port - no rolling road testing. So not sure how much detail they can get from that, but definitely interested to hear what your experience ends up being.

 

I have not had a visual inspection here in CA smog inspection for years now. They used to put the cars on the dyno with probe in tail pipe and run and different RPM's. Now they just hook up to ECU and it takes minutes and sends results directly to the DMV. I have not been required to smog my Vantage yet, probably next year. I have secondary cat deletes, but hear it will still past the test since they are not monitored. But a change in the ECU would no doubt throw up a red flag.

 

You didn't mention a tune, so if it has been tuned that's #1 to put back to stock. I would put the stock exhaust back on, except headers and catalyst to make it low key quiet as possible. Verify all the emissions monitoring has been completed and then go. Anything out of the ordinary and they will start looking for more. The headers are somewhat tucked away and they may not know exactly what they are looking at. A lot of places use mirrors to look under for a visual on the catalyst. If they are shiny I would alter the appearance so the blend in. Good luck no matter what you decide to do.
-JW

 

Please let me know what ended up going on with your emissions test. I've only tested with a stock system but have been interested in changing the exhaust and cats. I know we only need to do an OBD check here with exotics.

 

in ca. smogging involves inserting an OBDII reader in the socket and reading a few monitor statuses. there are free apps on android and apple phones that do the same thing. so it's easy enough to test your car yourself before taking it in so as to avoid disappointment, et. al. if the monitors have been run successfully as stated above, the smog technician sends an online report to the DMV to free up your license renewal status to "approved".

...oh and you'll be donating a few bucks ($60-80) to the smog shop owner, but no doubt the majority of that will go to the DMV/government. this fee will in turn permit you to pay an even MORE outrageous amount to the DMV for your registration.

 

Not sure about CO, but if it's same test as CA, then expect OBD test, visual inspection of emission system, which includes exhaust system, but anything after catalysts doesn't make difference if you have x-pipe after cat converters. Make sure put back factory software back & drive few miles to make sure all emission monitors are ready status.

 

I just went through this with my car. There is no visual inspection on newer cars, just an OBD II scan to validate readiness checks complete, and no pending/stored codes. I didn't have an issue at all. As it relates to the tune... this one is hit or miss. I have a friend that has a modified S6 that failed because of an aftermarket tune, and another with a highly modified C6 Corvette, including an extensive tune, that had no issues passing at all (three week ago, in CO). I would take the car to the local Air Care Colorado shop, and have it tested. They will likely have you stay in the car (they don't like to drive "exotics", run the test, and give you your results. If it fails, you can address things from there.

 

This has been my exact experience with AirCare with one exception. I had a tech test my gas cap for whatever reason and it failed, which normally wouldn't be a problem but it was a brand new gas cap and I had been waiting in line for over an hour. I told them it was brand new and that it shouldn't fail and the only option they gave me was to get back in line and test again. I came back later the next week and they stuck to just the OBDII test and that was it, so I guess YMMV.