The wife's new Yukon has 3 cats. Or what looks to be cats. Why? 1 coming off each motor manifold and 1 at the "Y" intersection. So if I can't have long tube headers in California, can I remove the 3rd in inline cat (@ the intersection)? The last cat does not have a O2 sensor. Or maybe get long tube headers, delete the 2 cats and keep the last one? How many cats does this state need? I did a search and could not find my answers. Thank you!
3 Cats?
- Thread starter totheyard
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07whitetahoe
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Federal law states that no emissions controlled device cannot be removed or altered. Converters are there for cleaning the air we breathe, and have been probably the single largest contributor to cleaner air in the US, in reference to automotive industry.
Last time I checked it is like a $3700 fine per offense to remove for the shop and individual. The EPA does check shops, and I live in Indiana, not CAL.
#1 why do you need to remove converters?
#2 How do you plan on passing emissions testing with them gone?
We do backpressure testing on factory exhaust systems, and with a stock muffler, 2 cats in-line, running at 3k rpm most vehicles won't produce .5 lbs of BP.
Last time I checked it is like a $3700 fine per offense to remove for the shop and individual. The EPA does check shops, and I live in Indiana, not CAL.
#1 why do you need to remove converters?
#2 How do you plan on passing emissions testing with them gone?
We do backpressure testing on factory exhaust systems, and with a stock muffler, 2 cats in-line, running at 3k rpm most vehicles won't produce .5 lbs of BP.
#1- Not all of them, just the ones or one that is not required. Because I do not want any (zero) lbs of BP.
#2- Thats why I am asking. My other vehicles only had one cat per exhaust system. 3 seems to be a little excessive. Why doesn't GM just make the entire exhaust one giant cat?!
#2- Thats why I am asking. My other vehicles only had one cat per exhaust system. 3 seems to be a little excessive. Why doesn't GM just make the entire exhaust one giant cat?!
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stevek
Full Access Member
I suggest getting long tube headers without cats and adding them into your exhaust.
The reason for so many is because closer they are to the motor (aka on the headers), the faster they heat up. Faster they heat up, the quicker they prevent emissions.
The reason for so many is because closer they are to the motor (aka on the headers), the faster they heat up. Faster they heat up, the quicker they prevent emissions.
SunlitComet
OBS Jedi-Do Good
it sound like the 3rd unit you refer to might be a resonator. if you remove it it is going to screw up the engine performance. it allows you to use mufflers with less back pressure and is used for exhaust tuning.
07whitetahoe
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There is a 3rd cat on some. They were put on for extra chemical changeover for passing emissions. Federal emissions will soon become CAL, and CAL in the future will continue to become stricter on emissions. Also, by removing them will change your fuel trim and result in poorer fuel economy as the computer is trying to level it out due to the rear sensors reading the output of non-existant cats.
The resonator is all the way to the rear, they don't put them in front of the muffler on these vehicles.
It is apparent in the automotive industry that no one knows how converters work, or why they are on there, other than the MAN trying to repress exhaust freedom on the working class.
They aren't hurting anything, leave them on there and shine some rims.
Sorry if I come off as overbearing, but having an exhaust shop and everyone going off of 40 year old thinking is very frustrating. Technology has changed so much in the last 5 years alone, but we can't get past these generational hand me down cliches that converters are bad.
The resonator is all the way to the rear, they don't put them in front of the muffler on these vehicles.
It is apparent in the automotive industry that no one knows how converters work, or why they are on there, other than the MAN trying to repress exhaust freedom on the working class.
They aren't hurting anything, leave them on there and shine some rims.
Sorry if I come off as overbearing, but having an exhaust shop and everyone going off of 40 year old thinking is very frustrating. Technology has changed so much in the last 5 years alone, but we can't get past these generational hand me down cliches that converters are bad.
"Also, by removing them will change your fuel trim and result in poorer fuel economy as the computer is trying to level it out due to the rear sensors reading the output of non-existant cats".
I wouldn't remove my cats because I need to pass the CA. visual. But in theory if you remove them, a custom tune could change the fuel back to the proper ratio? I have seen You tube videos (Not CA.) of new 6.2s with long tubes and zero cats running good. Some people want free flowing exhaust, a little more HP from a simple bolt on like long tube headers. Of course people will feel held down by the man. Pay the DMV, smog test and can not get the most out of my vehicle because of the air quality? No strict smog test are going to fix the SoCal air.
On a side note; if you are frustrated, help us understand what you know about current automobiles. I am not to good to learn something and I am sure many of us here are willing too. Its hard to read attitude through typed text, but I sense a bad one.
Thank you for the info!
---------- Post added at 12:18 AM ---------- Previous post was at 12:10 AM ----------
Its right after the 2 cats where the "Y" becomes one pipe. Before the muffler. I removed the resonator near the rear bumper with the Corsa cat back. While removing the stock cat back, I got a look at the so-called 3rd cat. It has the same honey comb style grid insides, just the bigger 3.5in in and out.
I wouldn't remove my cats because I need to pass the CA. visual. But in theory if you remove them, a custom tune could change the fuel back to the proper ratio? I have seen You tube videos (Not CA.) of new 6.2s with long tubes and zero cats running good. Some people want free flowing exhaust, a little more HP from a simple bolt on like long tube headers. Of course people will feel held down by the man. Pay the DMV, smog test and can not get the most out of my vehicle because of the air quality? No strict smog test are going to fix the SoCal air.
On a side note; if you are frustrated, help us understand what you know about current automobiles. I am not to good to learn something and I am sure many of us here are willing too. Its hard to read attitude through typed text, but I sense a bad one.
Thank you for the info!
---------- Post added at 12:18 AM ---------- Previous post was at 12:10 AM ----------
Its right after the 2 cats where the "Y" becomes one pipe. Before the muffler. I removed the resonator near the rear bumper with the Corsa cat back. While removing the stock cat back, I got a look at the so-called 3rd cat. It has the same honey comb style grid insides, just the bigger 3.5in in and out.
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07whitetahoe
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Yeah you can get a custom tune by wheatley or BB and they can probably work out the details. Front sensors adjust A/F mixture, rear sensors read the output of the converter (which is what will bring up a P0420, or P0430 code if they are inefficient, bad, or missing. But when those codes come on they will allow the computer to re-adjust fuel trim to try and level out the emissions.
I apologize for my attitude ( bad day ). When I read it, it seemed like you just wanted to remove them because they are on there, not because of any gain, but just for the sake of removing them.
Again I apologize for my attitude
I apologize for my attitude ( bad day ). When I read it, it seemed like you just wanted to remove them because they are on there, not because of any gain, but just for the sake of removing them.
Again I apologize for my attitude
stevek
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http://www.civicforums.com/forums/2...lug-non-fouler-trick-installation-w-pics.html
This is on a civic but the same applies to our trucks. Dummy O2 sensors made it easy but those are illegal now, so this is the next best thing
This is on a civic but the same applies to our trucks. Dummy O2 sensors made it easy but those are illegal now, so this is the next best thing
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