[VinnAY]

That's a lot of work for literally no gain, besides some sound.

[lokitwitch04]

Originally Posted by Nicul15

Dont breathe that shit. Not worth it. Either cut em off or don’t.

Get a axleback

The secondayr cats are full of a metal material they arent made of the same stuff as the primary's. I just gutted both. Very different material

[24v]

Originally Posted by KingLT1

You could do a cat back and get the borla X pipe that has resonators. they are basically the same thing as the factory secondaries units because they are not monitored by the ECU. AGAIN, You can't claim a part as emission compliant if the ECU doesn't monitor it. GM never intended for these to be a part of the emissions system, they were stuck in place to keep California happy.

Just because you don't understand the purpose of the secondary cats does not mean they are not part of the emissions system.

[Whocares05050]

Originally Posted by KingLT1

You could do a cat back and get the borla X pipe that has resonators. they are basically the same thing as the factory secondaries units because they are not monitored by the ECU. AGAIN, You can't claim a part as emission compliant if the ECU doesn't monitor it. GM never intended for these to be a part of the emissions system, they were stuck in place to keep California happy.

The secondary converts are part of the emissions system lol.



The monitored converters take a while to get up to temperature on a cold start. It is part of the reason cars have a high idle on cold starts for the 1st 45 seconds or so.



The secondary converters are to burn off the emissions while the primary converters are heating up. If you are doing a "sniff" test for testing, it would probably only fail on a cold start without the secondaries.



But I believe they are not required by LAW, just the primaries. However, I am pretty sure california will be requiring them soon...

[Dvs510]

Originally Posted by lokitwitch04

The secondayr cats are full of a metal material they arent made of the same stuff as the primary's. I just gutted both. Very different material

Did u have to remove the whole exhaust off the car to do it? What’s the trick if any?

[24v]

Originally Posted by Whocares05050

The secondary converts are part of the emissions system lol.



The monitored converters take a while to get up to temperature on a cold start. It is part of the reason cars have a high idle on cold starts for the 1st 45 seconds or so.



The secondary converters are to burn off the emissions while the primary converters are heating up. If you are doing a "sniff" test for testing, it would probably only fail on a cold start without the secondaries.



But I believe they are not required by LAW, just the primaries. However, I am pretty sure california will be requiring them soon...

We don't have "pre cats". Both cats on each bank are part of a "system" that takes the place of one larger cat. Also, all parts of the oem emissions systems are required to pass smog in California.

[KingLT1]

Originally Posted by 24v

Just because you don't understand the purpose of the secondary cats does not mean they are not part of the emissions system.

I understand the purpose. They are to help burn off emissions on cold starts being the primary cats are not efficient when cold. My point was they are not a part of the ECU's monitored emission system so you won't fail the OBD inspection by removing them. You could more then likely use resonators in place instead of going through the hassle of gutting the secondary units and still pass the inspection.

[Dvs510]

I think I might just get the 60606 and see if I can just use the small section replacing secondary and use clamp.. and that way when I need to for “certain reasons” living in California, then I can put secondary back in.. I just need to see if the one piece will fit without the original flex donut being in the way

[24v]

Originally Posted by Dvs510

I think I might just get the 60606 and see if I can just use the small section replacing secondary and use clamp.. and that way when I need to for “certain reasons” living in California, then I can put secondary back in.. I just need to see if the one piece will fit without the original flex donut being in the way

There is a pretty good chance you can pass smog without the secondaries in the car. I cut them off my 2011 Colorado v8 pretty much when it was new and it never had an issue. Just keep in mind that if you find a smog guy that knows his stuff, he may call you on it.

[24v]

Originally Posted by KingLT1

I understand the purpose. They are to help burn off emissions on cold starts being the primary cats are not efficient when cold. My point was they are not a part of the ECU's monitored emission system so you won't fail the OBD inspection by removing them. You could more then likely use resonators in place instead of going through the hassle of gutting the secondary units and still pass the inspection.

Just because they are not monitored does not mean they are not part of the emissions system, or not intended to be there. Putting a resonator in place of a cat makes zero sense. They are completely different, and if the smog guy knows enough to look for all of the cats on your car, he will also likely know the difference between a resonator and a cat.

[KingLT1]

Originally Posted by 24v

Just because they are not monitored does not mean they are not part of the emissions system, or not intended to be there. Putting a resonator in place of a cat makes zero sense. They are completely different, and if the smog guy knows enough to look for all of the cats on your car, he will also likely know the difference between a resonator and a cat.

I said they are not apart of the monitored emission system so you won't fail a OBD test or set a CEL...

The secondary cat is not constructed like a regular cat. It doesn't have the same catalyst material inside. I didn't say put a resonator directly in place...I said he could do the Borla Cat back system that has resonators in the X and likely pass. If not, It's a bolt-on solution that doesn't not require cutting anything and the OP could easily return to stock if need be. Or he could do just the X like I said before which would require a cut but still could be easily returned to stock.

Either option seems better then trying to drop the exhaust to cut open and gut the secondaries and reinstall