cat converter

[vman455]

My cat converter has gone bad and must be replaced. I was wanting to take it off. I was told if I did the computer would be told there is no backpresure and it would use more fuel. Any thoughts ?

[bigfoo]

It will adjust.. If you totally remove it you might have to modify the second o2 sensor because it takes a reading in front of the cat and also behind the cat to make sure it's working properly. If the secondary o2 sensor senses that the CAT isn't doing the job the pcm will add a little mor e fuel (darn emmissions bs)

but nothing major.. I wish you could disable it all..... you might be able to with a superchip or something since yours is a 94

[Scotty]

My cat converter has gone bad and must be replaced. I was wanting to take it off. I was told if I did the computer would be told there is no backpresure and it would use more fuel. Any thoughts ?

As you probably know some state inspections will not pass the vehicle if it is removed both for emissions and for the fact that it is not installed. What state are you in? Having to install a CAT when its time for inspection for me would outweigh the benefit received, Mike

[JasonA]

If you don't want the cat, you AT LEAST have to shove a pipe through it and leave the cat shell in place. I'm not at all suggesting you do that though...because removing the converter is a felony and finable up to thousands of dollars. Your state inspection probably at least has a visual check, and you'll fail that if you take the cat completely off (and you'll be lucky if they don't report you). If you put a pipe through it, you'd probably pass a visual inspection, but as noted, your emission test would fail, depending on what type of test it is. If it's a tailpipe sniffer test, you'd fail for sure, regardless of if you modified the O2 sensor or ECM.

Just do us (and our children) all a favor and pay the 200 bucks and get a new one installed. It doesn't take ANY power away that you can feel (maybe 1 or 2 hp), and your tailpipe emissions would be MUCH dirtier without that cat installed.

[bigfoo]

Get a high flow cat for $99 and have a shop weld it in....... easy:)

[93STS carmine]

If you don't want the cat, you AT LEAST have to shove a pipe through it and leave the cat shell in place. I'm not at all suggesting you do that though...because removing the converter is a felony and finable up to thousands of dollars. Your state inspection probably at least has a visual check, and you'll fail that if you take the cat completely off (and you'll be lucky if they don't report you). If you put a pipe through it, you'd probably pass a visual inspection, but as noted, your emission test would fail, depending on what type of test it is. If it's a tailpipe sniffer test, you'd fail for sure, regardless of if you modified the O2 sensor or ECM.

Just do us (and our children) all a favor and pay the 200 bucks and get a new one installed. It doesn't take ANY power away that you can feel (maybe 1 or 2 hp), and your tailpipe emissions would be MUCH dirtier without that cat installed.

I cleaned out my cat ,put back on and it sounds great. And the best thing ,I live in S.C. We dont have any emission test, the less uncle sam is in your business the better.

[JasonA]

I cleaned out my cat ,put back on and it sounds great. And the best thing ,I live in S.C. We dont have any emission test, the less uncle sam is in your business the better.

Yeah, you and I probably won't notice any difference, but it'll sure make it hard for our kids and grandkids and their kids to breathe...

[Scotty]

the less uncle sam is in your business the better.

I dont think this is an Uncle Sam thing. Car manufacturers respond to regulations and competition, they would never spend extra money to improve emissions or safety if it were not required. There are many examples of manufacturers dropping the ball (Ford Explorer comes to mind in terms of safety). Visit, Los Angeles, Phoenix and New York and look at the pollution in the air and you start to understand. The NS runs very clean and is very powerful, removing the CAT adds what to it 5 HP at best? I understand the CAT back modifications, intake, etc. But I have never understood why it was necessary to remove the CAT to gain a couple of HP. The so-called CLEAN RUNNING LOW EMISSION Japanese burners have terrible emissions with the CAT removed, and it happens all the time, for what purpose, a tenth of a second improvement 0 - 60? I am all for small government, but standards need to be adopted and enforced for street cars and trucks. Personally I am thrilled that New York State and New Jersey has stringent emissions testing and in spite of that, lots of high emission cars get by as the inspection stations rig the test and close their eyes. There has to be a watchdog.

[JasonA]

Personally I am thrilled that New York State and New Jersey has stringent emissions testing and in spite of that, lots of high emission cars get by as the inspection stations rig the test and close their eyes. There has to be a watchdog.

Unfortunately, people don't care unless you make them.

[bigfoo]

If we would just all tune our engines to the point where they burn so efficiently that we don't need a CAT ... then it would be cool :>

[JasonA]

If we would just all tune our engines to the point where they burn so efficiently that we don't need a CAT ... then it would be cool :>

At the risk of taking this thread wildly off course...

In general, I agree. I offer a slight change to the statement: "if we could tune our engines to the point where a catalytic converter proved to be of no benefit...then it would be cool." As it stands, at least the way I understand it, a converter proves to reduce emissions even on the most efficient of engines; meaning there's always a gain to be seen by using one. And we all know (or should by now) that a modern catcon reduces horsepower very little...maybe 5 hp at the outside on a Northstar (obviously varies with engine design, exhaust design, etc). The days of inefficient pellet converters from the 1970s are way gone...you shouldn't be able to notice a performance difference if you remove your converter. If you do, it means your old one was plugged or otherwise defective and probably wasn't providing a benefit to the environment anyway. A new converter, as stated, won't run you more than one or two hundred dollars, installed, which is also quite a bit better (less expensive) than it used to be.

But the threashold for emission compliance is, I suspect, going to be a moving target...as it should be. As we get more efficient with our designs, the pressure to reduce them further will mount, and I suspect the converter will always prove to be a benefit. But I could be wrong. We've seen the departure of one of the first emission control devices...the EGR valve. As I understand it, the RWD design Northstar doesn't use an EGR valve. Perhaps we'll see the same with catcons one day in the distant future.

My other hobby is small engines (lawn mowers, gas trimmers, etc) and they're talking about developing after treatment (catalysts) for those engines, which I completely support. If we treated this earth like we actually planned to stay here for a while, there would be no need for government legislation against pollution, etc. But the problem is we don't (treat the earth like we plan to stay), and if we don't pay for it, our kids and their kids will. I've said before on another auto forum that everyone understands our impact on the environment, and understands our responsibility to our offspring to maintain the cleanest environment we can. You just get labeled as an "environmentalist" if you actually accept and act on those responsibilities.

[bigfoo]

Exactly.. I vote we put catcons on diesels, lawnmowers, motorcycles, boats, etc.. Sure it's good to have them on cars, but what about all the other stuff ? Heavy equipment(dozers, loaders, cranes, etc.), generators, tractor trailers, boats, atv's, cycles, etc.

[vantasticdude]

carbon emissions from a diesel or CO2 from a car ............... I'll take a diesel . I'd consider one of those diesel 350 caddy's if I could find one

[cad98]

First off I live in So Cal and after cats came out our smog dropped almost 80% just replace the cat .....now Tractor trailers allready have been controlled.