Removing Secondary Cats???

[SRTRICKY]

What effect on emissions would there be by removing just the secondary cats vs. keeping all four in? Would it be hard to pass emissions with the secondary cats out? Thanks in advance.
Ricky

 

[SRTRICKY]

and do I just cut the cat off and weld on a new piece? do any sensors need to be replaced/moved?

 

[Viperfreak2]

Not to my knowledge. I plan on doing it soon. O2 sensors are before this section.

 

[Paul Hawker]

My understanding is that cars with secondary cats removed will pass emissions testing in California, when the primary cat is still new, and has not degraded. After a few years the car will fail, as the single cat will no longer be capable of the task. Dual cats are necessary to meet 100K miles gov. requirements.

 

[Skip White]

I wonder if the Vec2 would help emissions, as it is common knowledge that the SRT runs very rich across the board. The rich condition must be causing a huge difference in emissions. I don't really know. Someone should run a sniffer test, at the local, inspection center, and then install the Vec2 retest the car. I really wonder. Or you could get a really lean card for the test. Paul do you really think the primary cats would degrade enough on the car to fail a sniffer test? Seems like if the car will pass with the sec. cat delete, in Calif. and that's about as tough as it gets, it would forever pass in other states.

Skip W

 

[SRTRICKY]

After a while just replace the first cats with the second cats and you have brand new cats again....or does this not work

 

[Skip White]

Won't work. The primary cats are much bigger than the sec. cats.

Skip White

 

[SRTRICKY]

Oh I defenetly learn something new here everyday

 

[Paul Hawker]

Skip.
My comment on "fresh cats" came from a tuner with many years of experience with Vipers. The reward is small for removing one set of cats. The original question was regarding emissions.

In California I would be hesitant to remove cats. Maybe you can get away with it, but then again, maybe not. One set of cats puts you right on the edge. If you fail the sniffer, then a visual inspection revealing removed cats could open up a can of worms with the State. They are beginning to take removal of emissions equipment very seriously. Unless you have a STRONG reason to remove the converters I would leave them in.

A Corsa exhaust system by itself pushes the noise limit. Start removing cats and the noise also becomes an issue with side pipes.

Don't know how much power you gain by removing one set of cats, but don't think it is a lot.

 

[Nsane1]

In TX, I recently failed my emissions testing. All they do here on new cars is hook up the OBD system, and since the secondaries are removed, the o2 sensors (which are after the forward cat) report a boatload of codes. At least 4 codes were being thrown. So I failed...

Be careful, I was shocked to say the least, I thought the o2s would never know. I suspect I would fail even under the sniff test, as it runs very rich now. I wonder if the gen2 o2 sensor plug-in would work.

 

[BigSnake]

Nsane1,

I have a SRT-10 with the secondary CATS removed. I will get my car inspected in Collin County in July. I was thinking that my car would pass due to the fact that the O2 sensor is located after the primary CAT.

What county did you fail your emission test? Do you have a Gen2 or GenIII?

 

[TedK]

Perhaps you should consider purchasing the hi-flow cats from parts rack. If ordered with the 2.5" outlet, it is a direct bolt-in replacement for all the original cats. Only two cats with this system. You could then save your original four and return the car to stock when necessary with a little work. Benefits are cooler running and weight reduction, possibly more power-but with the first two who cares? I am considering this for myself, cat-backs are not for me as I like the car QUIET. Hell, just to show you are a good citizen you could leave the sills off when you go for inspection so they could see your originals still in place.