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The problem is when you eliminate the cat(s), you must then reprogram your emissions system or the sensors will tell the computer there is a problem and the computer will adjust fuel mix, timing or whatever and your car will not run properly, you will lose HP or MPG or both. You may even get sputtering, backfires, or other more serious problems. The car is designed to run on a computer system calculating in a Cat, usually with sensors on each side of the cat, but always on the down-flow side. Reprogramming the computer to function without a Cat is seriously complicated. I have seen chips that claim to do this, but I have also seen articles saying those chips do not work at all. For me, in the few instances I had to bypass a cat, the car was on its last legs and we just lived with the check engine light on all the time and the terrible MPG and reduced performance. It did not really matter, we just needed to get some more months out of the vehicle so we could prepare to replace it.
IS this something fairly recent? I had an 2008 Dodge Ram that I used for towing a lawn care trailer, the CAT and muffler were removed, it was basically straight pipe from the engine to the tail pipe. It ran the exact same, MPG stayed about the same. I was expecting it to be extremely loud, but surprisingly it wasnt, it sounded more like a 'souped up engine' than anything else.
IS this something fairly recent? I had an 2008 Dodge Ram that I used for towing a lawn care trailer, the CAT and muffler were removed, it was basically straight pipe from the engine to the tail pipe. It ran the exact same, MPG stayed about the same. I was expecting it to be extremely loud, but surprisingly it wasnt, it sounded more like a 'souped up engine' than anything else.
Not sure which RAM you had. I think the 5.7 has two cats and 4 sensors, so if you remove the cats, especially if you remove one Cat, you are going to have problems. Maybe your RAM was a smaller engine version or maybe you just did not notice, however your check engine light would remain on and would throw a code for an O2 sensor.
Many of what was formerly unique equipment that was due to the "California Emissions" is moot now since more and more manufacturers make 50-state vehicles that all meet the stricter CA emission standards. The requirements for regular passenger cars are mostly met by the same kinds of equipment present on other cars that don't meet the standard, but just with greater number and/or more effectiveness. Like for example additional catalytic converters or O2 sensors, plus the OBDII (On Board Diagnostics) support for monitoring and managing that extra equipment.
Correct. California cars used to have different EGR systems than the other 49 state cars, but they're all the same now.
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Originally Posted by phantompilot
Actually that was a 60s thing that lasted about 10-15 years and just referred to air injection, which means that you pump fresh air from the engine compartment into the exhaust manifold in order to help reduce the amount of unburned hydrocarbons, since at that point the gas is still hot enough to support a little additional combustion (and it just needs some additional oxygen to do that). On my dad's Ford, it was called the "Thermactor" system. There was of course, a pump that was powered by an accessory drive belt. In all it was actually kind of a pain in the butt, because it added a lot of extra tubing/clutter to the engine compartment. It also was parasitic, robbing a little bit of power from the motor...so car guys hated it. On a non-CA car the engine was much cleaner looking and easier to work on because you had less stuff getting in your way. And, MORE POWER!! ARGH ARGH ARGH!
But, this was mostly rendered moot by the introduction of catalytic converters, which do basically the same thing.
So modern cars use a variation on the old "air injector" system, but its really just a part of the catalytic converter system now. And since 1975, all cars sold in the US have been required to be equipped with catalytic controls.
Not exactly.
Air pumps and catalytic converters are related only in the sense that both are used to reduce emissions. They are two separate systems on cars. All cars will have catalytic converters. For smaller engines, they'll usually have two, a pre-cat and then the main cat. For larger engines, there will usually be 4, 2 precats and two main cats, or possibly just one large main cat if the exhaust merges together.
All our cars have air pumps as well. (Porsche calls them the Secondary Air pumps, and there are two of them on my 911. Our Cayenne also had them.) They only operate on start up, until the engine reaches a preset operating temperature, and then they shut off. Our Mercedes vehicles have them as well.
I am not sure if every vehicle is equipped with an air pump for emissions, but I know pretty much every German and Japanese car uses them to this day. If they no longer served a purpose, manufacturers wouldn't be including them.
Is it a gizmo in your car that regulates it? Is it just a number of particulates required by the state DMV? Is it some kind of special catalytic converter?
I'm asking because I'm probably buying a used car in California, and I live in New Mexico and will be driving it back.
In short, do I need to be worried about it? Especially about future repairs, performance, etc...I keep reading it in the car ads and seeing it.
Thanks all.....
I own a repair shop. Every time we get a car that has not been here before we log in VIN, mileage, color, EVERYTHING. Maybe 9 out of 10 relatively new cars I log in comply to CA emissions these days. I am not quite to the point of entering "CA emissions" without looking at the emissions sticker, but getting closer to that! We work on Asian makes more than anything else, some domestic, nothing European. I am in Texas.
I don't think the car being held to stringent emissions standards is a bad thing. Los Angeles has far less smog than it did decades ago. My wife and I drive Hondas. We get good gas mileage, flawless gas pedal response and I have yet to have to perform repair or maintenance on our cars that was necessitated by strict emissions standards.
Catalytic converters are frequently to a higher standard for CA emissions than 49 states. In our shop right now is a 2005 Honda Civic, CA complaint emissions, with a cracked exhaust manifold. The exhaust manifold and the catalytic converter are a combined assembly. The CA compliant assembly is a different part number than 49 states, but there was not much difference in price.
Correct. California cars used to have different EGR systems than the other 49 state cars, but they're all the same now.
Not exactly.
Air pumps and catalytic converters are related only in the sense that both are used to reduce emissions. They are two separate systems on cars. All cars will have catalytic converters. For smaller engines, they'll usually have two, a pre-cat and then the main cat. For larger engines, there will usually be 4, 2 precats and two main cats, or possibly just one large main cat if the exhaust merges together.
All our cars have air pumps as well. (Porsche calls them the Secondary Air pumps, and there are two of them on my 911. Our Cayenne also had them.) They only operate on start up, until the engine reaches a preset operating temperature, and then they shut off. Our Mercedes vehicles have them as well.
I am not sure if every vehicle is equipped with an air pump for emissions, but I know pretty much every German and Japanese car uses them to this day. If they no longer served a purpose, manufacturers wouldn't be including them.
Oh sure they serve a purpose but as mentioned they are just integrated into the modern cat-based emissions system . The reason they would shut off btw is if they cannot offer any additional benefit once the cat gets hot enough to actually work. It’s not the engine temperature that triggers it- it’s the cat coming online. Direct air injection into the manifold or header is only needed to meet the “startup emissions” test. Some models switch that over to the cat itself once it’s hot. If yours turns off it’s because that isn’t necessary/useful. Like for instance if you have a turbo model that might be the case.
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We work on Asian makes more than anything else, some domestic, nothing European. I am in Texas.
