Does anyone know of any companies that are working on or have completed a cat-less exhaust system?

 

isnt that illegal

 

Anything that removes or alters the emissions control systems in any way has to marketed as a "race only" or "off road use only" system. In the state of Texas it is actually illegal to remove your own emissions systems although no one enforces this law. Many people think that it is only illegal for a shop to remove them. Remember that the RX-8 is very computer controlled. The car also has 2 O2 sensors. One before and one after the cat. It compares both signals and tells the computer if something is wrong or not. Who knows what kind of signal the computer will receive if you remove the cat. The Camaro's have a part available called an O2 simulator which plugs in where the rear O2 sensor was (before the cats were removed if they were) which sends a false signal to the computer so there is no error code. Maybe we need one for the RX-8 as well. It is just a resistor. The question is, does the computer go off of any reading in a range or does it constantly correct for different ones?

 

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Yes, I know its not street legal and I'm pretty sure the check engine light will come on at random times while im driving, but there are ways I'm sure to trick the O2 sensors like you mentioned with the camaro. Any info on how to go about it would be appreciated.

 

SR Motorsports said that have released a "mid pipe" at the sevenstock event. They said they had got 11 hp gain on the dyno and also picked up some torque. They are also going to work on
a free flow cat system. They said the "mid pipe" was released the
week before.

 

i am thinking of removing my cat tomorrow night...just for the night to see what it sounds/runs like.....if it runs! i was wondering on top end i think it is going to sound more beastly wouldnt you think?


andrew

 

In Florida it is not illegal to remove your cat from your car. I actually know a lot of people who have done it etc. I hear HP gains of almost 10HP when removed from most car's. I am looking into a non-cat back as well. I just don't want to mess around with screwing up the computer. That's why I think I'm going to wait until at least the new year before I start moding my 8. Just seem's like more info will be out by then.

 

haha mike i dont know why i find that quote funny.....but i think its freaking hilarious!, i think its just the tone...haha just had to say that


andrew

 

I was wondering what it would take to replace the cat in the 8 with a straight pipe that has an o2 simulator installed...i've heard some people mention multiple cats...oil injectors....can someone give me a description of the setup and what I'd have to do to get around it? any predictions on performance gains would be great also. thanks.

 

A complete disregard for both the law and the environment, for a start.

 

Nothing like a knee-jerk, petitio principii argument to answer someone's question. You assume an awful lot with an answer like that and it puts you way out of your depth.

I'd suggest a real O2 sensor rather than just a simulator.
I haven't gotten my hands around that part of an RX-8 yet, but I suspect the gains would be minimal without the requisite fuel re-mapping.
Without the O2 sensors you would just have a crappy running car.

 

Ecc are u a treehugger?

 

Not at all. Lord knows I used to have an abundance of disdain for EPA requirements in my youth, but these days I do tend to see the bigger picture. I'm far from being a greenie, but I do acknowledge that the rules are there for a reason.

If the car is going to be used for track work only, then go for it. But if it's going to be used on the road every day, and thus contribute to pollution which will result in both lesser quality of life and more stringent emission requirements for every other law-abiding driver, then yes, I have a problem with it.

 

I'm with you on that issue eccles. I think it's absolutely frightening how people remove their cats (or worse gut them) for just regular everyday driving without a single though about the consequences.

 

Both of my Mazdas pass the fairly stringent Maryland emissions tests without any catalytic converters at all (just a catalytic-shaped "test" pipe.
Tuning is far more important than a catalyst. The cat was designed to make up for the slothful habits of the average vehicle owner.

 

However, with the advancements in Cats, the resistance across them is so minimal, the gain's, at least in my opinion, aren't really worth the extra pollution. What would be better (at least in my opinion) is just to have a complete new system made from header back, using some larger cats, which will produce less pressure drop, and give more power, without wrecking air quality.

 

Neither of your mazdas are rotaries, which barely pass emmisions as it is.

 

If you're driving in traffic, it doesn't matter if you have slothful habits or not. And guess what, those areas that have lots of traffic are exactly where you would want stricter emissions laws. And how are cats making "up for the slothful habits of the average vehicle owner"? What are you talking about?

I know that replacing the cat with a test pipe would be very cheap, but I still say that it's still not worth it. I wouldn't want my $30k car spouting the poisonous fumes of a American car from the 70s.

 

Do larger or "high-flow" cats work as effectively as their stock counterparts in controlling emissions?

 

Most do, the way a cat works is that when at high temperatures, the gases in contact with the catalyst (a combination of Platinum and Palladium) cause many harmful compounds to be converted to not so harmful compounds. Specifically:

Carbon monoxide changes into carbon dioxide.
Nitrogen oxides change back into nitrogen and oxygen.
Hydrocarbons change into carbon dioxide and water.

The effectiveness of a catalytic converter is controlled by two things.

1. It has to be hot enough to cause all three reactions to occur
2. It has to have contact for long enough with a majority of the gasses. This is why they are usually a honeycomb, so that the gasess are never far from the catalyst.

Most high flow cats are physically larger, so that with the same size honeycomb cells, but more of them, the gasses are just as close to the catalyst, but since there are more holes, there is less restriction.

 

Thanks for information, it was very helpful.

 

Maniac where in maryland are ya?

 

Generally just in front of the big cloud of poisonous gases

 

I've been to Birmingham and the air there is hardly clean. By comparison, it is crystal clear here - we don't have "ozone alerts" or other breathing issues, even in the summer.
So get stuffed JohnnyCumQuickly.

I'm really surprised to see how reactionist, left-leaning and illogical some members of this group are.

If every privately owned motor vehicle in the US suddenly had no catalytic converter, the increased smog output would still be less than half of what is put in the air by total output of commercial vehicles today that are NOT under the same restrictions because of effective congressional lobbying.
Commercial vehicle traffic - trucks, busses, trains and aircraft - produce nearly 90% of the total pollutant content in the air over North American urban areas and they are almost completely unregulated.
Take all of the pollution ejected into the air by human beings in one year and it still accounts for less than 10% of polluting content present - mother nature is the biggest polluter of all.

I'm in Gaithersburg. Feel free to come breathe the air....

 

Keep in mind that one of the important factors affecting air quality is the weather system and topology in the area. This is why the LA basin is so bad. There are planty of areas where more pollutants are created and put in the air, but because of the way the air passes through the area, it makes a world of difference. However, poluutants are pollutants, and while they may not be building up in your area, odds are any extra pollutants produced there are building up where the winds trap them... like the LA Basin, and, I'm guessing, Birmingham.