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Discussion Starter #1 (Edited)
First off, I did do a search and couldn't find a clear answer to this...

I was wondering if anyone can shed some light regarding the removal of the secondary cats and emissions testing.

I am about to install a full exhaust without cats but retaining the stock headers and primary cats. I know that both the pre-cat and post-cat O2 sensors are situated with the primary cat, thus I shouldn't have any issues with any CELs. I was wondering if I will experience any issues trying to get my car emissions tested (BTW, I live in VA) without the secondary cats.

Basically, did your secondary cat-less beast have any problems passing state emissions testing?

Any help would be greatly appreciated!

Thanks!
 

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Emissions

Your vehicle emissions will be determined through your OBD diagnostics port. I am not sure about where you live if the tail pipe test is still the standard method of testing or if they are utilizing the IM240 dynanometer testing. On 1996 or newer cars at least here in Maryland they are utilizing the OBD diagnostic port and have also eliminated the IM240 and utilize the tailpipe test only for those vehicles that have been manufactured before 1996. I would assume that all emissions relevant to our vehicles are monitored by the vehicle ECU. Since the primary cats fall within the monitioring capability of the ECU and will be reported out via the OBD to the testing facility, keeping the primary cats in place would be wise. I could be wrong but the secondary cats are not monitored by the vehicle ECU, probably making it relatively safe for you to install the complete sections 1,2, and 3 RPI exhaust. However, you must be keenly aware of the method of emission testing your State or District employs i.e. OBD, IM240 or tailpipe. Most states measure, Hydrocarbons, Carbon Monoxide and Oxides of Nitrogen in ppm (parts per million). Bear in mind that it is a violation of Federal law to remove any emissions or emissions related equipment and most states follow those regulations. You will have to find an independent exhaust shop that is willing to remove the secondary cats. Some States/Districts or even counties within a state maybe exempted from a States emissions standards if your vehicle is registered in that affected area. I'm sorry if I've given you too much info. but we all have faced the same delima, "To Cat or Not to Cat". Do your due diligence and good luck with your mods.
 

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Discussion Starter #3
DFrankm,

Thanks for the prompt reply and useful insight. Unfortunately in VA we use the exhaust probe as opposed to the OBD. For a short period VA even used the dyno to simulate driving conditions. But recently they have reverted to just the probe. I believe you are correct that the O2 sensors are situated on the primary cat, so no OBD related CELs should result from my exhaust mod.

Hopefully I can get past emissions after the install. I definitely do not to go through the whole exhaust re-install just to get past emissions.

Your vehicle emissions will be determined through your OBD diagnostics port...
 

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why do you want to remove the secondary cats?
For more HP and better sound of course :thumbsup:

You will not have a problem. All you have to say if they don't see it is "look on the headers...they are there". The shop guys don't know anything, and with the primaries it will definitely pass inspection.
 
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