A few times in the past in some other threads I have expressed my disapproval of people removing the catalytic converters from their street driven cars. It was pointed out (quite correctly) that I was dragging a thread off topic, so I decided to start a thread to discuss the legal, environmental, and ethical implications of removing your cat. In short, I believe it is stupid and selfish to do so, and in a series of posts I'll explain why. Reasoned debate and added information is welcome. Flames - well, don't bother.

A bit about me: I grew up in the hills south of Los Angeles during the 60s and 70s. On a clear day, like after a winter storm had come through, I could see clear across the LA basin to the hills on the north side and see the "Hollywood" sign. On a bad day, it would all just be solid brown, the air hurt to breathe, PE at school would be cancelled and we'd all have to stay inside. I'm not a whacko environmentalist, after all I drive a Mini instead of a Prius or riding my bike everywhere. On the other hand, I ski, sail, scuba dive, backpack, and go for 50 mile bike rides so preserving our environment and clean air is important to me. I also consider myself a car guy, not as extreme as you guys who do some amazing engine builds but I enjoy modding my R56S. I grew up with motorcycles and karts and helped my dad rebuild the engine on our VW bug. I have done a lot of work on my various cars, I follow F1 and other racing and have been to the track to watch auto racing live, I also track my Mini. So I understand the desire for better handling and more power. I just installed a Wagner FMIC and plan on getting a tune for my car in the future.

I plan to split this into a few sub-topics:

Legal: the potential legal and financial consequences of removing your cat.

Environmental: What removing your cat does to your car's emissions, and why that's a bad thing.

Ethical: Why I think it is stupid and selfish to remove your cat.

 

Legal: This one is pretty simple. Removing your catalytic converter or otherwise disabling parts of your emissions control system is a violation of Federal law, with a $2500 fine. If a shop or dealer does it, it can be a $25,000 fine. California has an additonal $2500 fine. You'll never, ever pass a sniff test, no matter what tune you put on the car.

In CA, new cars are exempt from emissions testing for the first 6 years, and the chances are that unless you're a complete idiot you won't get busted for being catless. But if you are busted, $5K in fines can be a substantial percentage of the value of your car.

 

From the research I have done, I think the 3 way catalytic converter is one of the great triumphs of science and engineering applied to internal combustion engines. Catalytic converters are amazingly efficient (over 90%) at removing Nitrogen Oxides (NOx), Carbon Monoxide (CO), and unburned hydrocarbons from the exhaust stream by converting them into Nitrogen (N2) and Carbon Dioxide (CO2). N2 is 70% of the atmosphere, and CO2 is what we mammals exhale. Plants and trees and living green things take in CO2 in the course of photosynthesis, keep the carbon, and release the oxygen. (CO2 also happens to be a significant contributor to global warming but I'm not going to argue that topic.) Obviously eliminating your cat means all that nasty stuff goes straight out the tailpipe and into the atmosphere. Go research how catalytic converters and modern engine controls work, it is really an impressive accomplishment.

Let's start with NOx - the primary concern is NO2. NO2 is extremely toxic all by itself. It combines with water in the atmosphere to produce acid rain. It is a precursor to photochemical smog. Do your own research, this is bad stuff, and eliminating it from your exhaust stream is a good thing. There are a lot of good reasons that we have air quality regulations, and the damage that N0x can do is one of them.

Carbon Monoxide - while CO is produced and used naturally in trace amounts in our bodies, in very low concentration in air it is toxic and can be fatal. This is the stuff that kills you when you use the barbecue to heat a confined space or run your car engine in a closed garage. It is also along with NO2 a component of photochemical smog and a contributor to the formation of low level ozone.

Unburned hydrocarbons - ever been behind a 60 car at a stop light? Stinky. And those hydrocarbons are another contributor to smog. Enough said.

 

I think it is selfish and stupid to remove your catalytic converter from your street car.

1) you make yourself vulnerable to stiff fines. But I guess you don't care and think you won't get caught, and all the vendors cover their butts by saying "for off road use only" (nudge, wink). It is selfish to say "the rules don't apply to me" just so you can get a few more HP and bragging rights on a dyno sheet. And how often do you actually use those extra HP? While your catless engine emits an order of magnitude more pollution with every exhaust stroke. Is it worth it?

2) You turn your car into a gross polluter to gain 10 - 20 HP. Consider the engine in the Dodge Challenger Hellcat - it is 6.4 liters and 707 HP, so roughly 4 times the displacement and 4 times the horsepower of a stock N14 or N18. Assuming that the Mini engine and the Hellcat engine turn gasoline into HP with roughly the same efficiency, then the exhaust volume and therefore volume of NOx, CO, etc are going to be roughly proportional to displacement - i.e. the Hellcat engine will produce about 4 times as much as the Mini. If I'm way off on that, someone with expertise on the topic please correct me. Assuming the cat on your Mini is 90% effective, when you remove it your emissions go from 1x to 10x. Congratulations! Now your Mini makes another 10 - 20 HP, and pollutes more than twice as much as a 700 HP engine. That's just stupid. If you want/need a car with 250+ HP and think that deleting your cat is the way to get there, you bought the wrong car. There are plenty of fun to drive cars that produce over 250HP in stock form with their catalytic converters, go buy one of those. If it has to be a Mini, then go get a tune or a bigger turbo, just leave the cat on.

3) I have heard the argument "look at power plants, or jet airplanes, or methane from cows, they produce way more pollution than my Mini, any increase from my Mini without a cat is insignificant." Yes, and when you think that way, you end up with foul air and all the health problems that come with it. Go do a google search for pictures of smog in Los Angeles in the 1970s. Go visit Beijing or Mumbai or Dehli if you want to experience it first hand. That's the result of everyone saying "well nobody else does, and even if I did it wouldn't make any difference, and it's expensive so why should I?"

Do you throw your garbage out the window when you're driving? Do you get one-time use plastic bags at the grocery store and throw them in the ocean? Do you go pee in the stream above your campsite? Do you take a dump in your backyard? Maybe some of you do, and I hope you don't live near me. By removing your cat, you're not only polluting of your own environment, you're polluting the environment for the rest of us as well.

I seem to be the only voice on NAM saying this is a bad thing, on other forums there are a lot of people who disapprove of removing cats.

OK, I have vented. I hope this makes at least a few people think about the implications and choose not to go down the catless downpipe path.

 

I agree with your facts and for that matter your opinion also. I have never removed a cat from one of my cars except to replace it.

 

I think that you'll find the increase in emissions from cars that have removed their catalytics is insignificant from a big picture point of view.

 

I find it interesting that the vegan community is now using climate change as an argument against eating beef.

The huge number of ruminants roaming the Earth was heating up the planet due to all the belching and farting of greenhouse gases. Then along came humans, driving the animals nearly to extinction. The result a mini ice age. Or so the story goes.

Regardless if you believe the above or not simply Google cow methane production and you will find numerous hits stating cattle and other ruminants contribute 20-65‰ of greenhouse gas emissions depending upon where you live.

Developed countries cannot expect developing countries not to use polluting technologies.

If you really want to make an impact how about contributing monies towards research into cheaper energy alternatives, getting us off inexpensive fossil fuels, instead of towards cancer research?

I would rather exert time, effort, and money looking for cheap viable solutions to the fossil fuel and climate change issue than wasting it on laws and enforcement.

Oh, and don't remove your cat unless your on the track.

 

Great post to get people thinking and start some (hopefully civil) conversations!

 

I do appreciate your opinion and stance on this but It will not make me put my cat back on my car because it's not just 20hp loss. If I'm running my catted down pipe I can no longer run my tune because of the loss of flow and how restrictive it is. I am still running both of my other cats so I'm not really concerned about deleting one. My personal opinion. You are entitled to yours and I'm entitled to mine. I would never try and change yours but I also know you won't be able to change mine. In theory following the laws I could go buy an 89 mustang 5.0 and run straight pipes out the back and be perfectly legal because it's old enough. I think me removing one cat isn't going to make a whole lot of difference.

 

I agree with OP.

However, our cars have two small cats and when I do do a full exhaust overhaul those are both going away (they have 90k of emissions decreasing their effectiveness anyways) and utilize a substantially larger hi flow cat that would typically be used on a v8. I feel *** though that should give me the best of both worlds

 

I also started driving in the 70s, in LA.
I remember the smell and eyes burning on the freeways.

Today, I hate driving behind someone with their cats removed, especially in traffic.
Its easy to tell with all the unburned hydrocarbons.

 

Getting behind a decated car on a group ride sucks...the stink...enough to give you a headache...
Yup...it needed to be said...
90% of folks that do it just do it cause "the cool one are".... Reality is, they are doing it to a daily driver, stinking up the area, reducing their cars value, and incurring a huge risk...

 

Although allergic to cats, I fully support the OPs position.

 

Agreed on all points with OP. In comparison to a nicely tuned/custom full cat back system on most turbo equipped vehicles, a catless R55s and R56s sounds like a piece of old farm equipment anyways....

 

Lets see, I get behind farm equipment. buses, horrible Harley Davidsons, any car from 1972 and earlier and most any diesel and I should deal with it, which I do. All those veh can be considered offensive to people and the environment. But wait...

But, god forbid someone gets behind a Mini w/o a cat!!!
That selfish Mini owning and modifying

Why should I have to buy a 5.4 liter piece of crap in a larger bodied piece of crap just so I can have the performance that I desire when, from a much smaller machine, with less weight using less fuel ultimately creating a better performing machine?

I'm sorry I do digress.

It's funny and timely as I'm having a 3" DP installed on my Mini as I write this and have absolutely no problem with it.

Am I trouble now? LOL

 

!!

 

Seriously... someone is trying to equate the

 

This is not an appropriate forum for politics. Let's keep the discussion to MINIs or cars in general and leave the politics for somewhere else.

 

Pruned the thread...and here is a friendly reminder for those who's seem to need it.

I'll be back later to determine fate of this thread.

 

I am sorry. That was the point of my post although it seems it was overshadowed by my sarcasm overshadowed it.

I went to this thread thinking it would answer some questions and instead I found it to be a rant related to political views so my post was simply asking that we keep the conversation to Minis (yes by using sarcasm that directly opposed the previous post).

 

Reality is the site bans all discussions of illegal acts...speeding, etc...
So talk of de-cated downpipes, etc outside of track threads already show lots of flexibility from the site....the MODS have a awfully narrow line to walk....
My view..on many older cars, de-catting was easy HP...big HP in some cases...
But by the mid 90's, cat's become more effecent, and much free flowing to help mpg'¢...
So the gains today vs the risk of fines, The stink, the DECIMATION of resale value makes decatting crazy for anything but a track car....

 

As far as Guideline #5 goes Tim, I interpret that one being reserved for M/V moving violations. Especially since 40% of the mods and parts being sold/discussed here may not legal in some states.

Carry on.

 

Tl:DR

The plastic and garbage you generate every week do just as much harm to the environment than no cat on your mini.

 

When u think about it, we all have a negative effect on the environment mostly unintended.
For the very few that remove their cat, does one really think they doing great harm?
There are so many internal combustion engines out there w/o smog. Boats come to mind.
Should we demonize these boaters. I say fight the fight that has an effect on the outcome.
This forum caters to those that wish to modify, legal or not, intended or not.

 

If a car has a functioning cat that works why remove it? If the answer is for more performance there are high performance cats available. I had a the cat go bad on my MINI & I replaced it. Just my .02....