Catalytic Converter: How It Works | Science Garage

Exhaust has a lot to do with performance. Catbacks, Mufflers and resonators get all the attention, but the Catalytic Converter is super cool too! It’s an amazing design that changed the way we think about driving. Catalytic Converters have helped gas engines a viable means of transport while drastically reducing emissions. Bart cuts one open to see what's inside, and he explains the reactions they facilitate to turn exhaust from nasty to nice.
Bart teaches us how cars work by blowing stuff up and cutting things in half. It’s a science show for the car lover who’s easily bored. Join Bart as he explains the science behind everything automotive. This is cars down to the atom. This is Science Garage.
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Donut Media is at the center of digital media for the next generation of automotive and motorsports enthusiasts. We are drivers, drifters, and car enthusiasts who love to tell stories.

[@arnaldojansencarino5391]

An addiction to Donut that wont result to diabetes.

[@jakelamb39]

Arnaldo Jansen Carino i have Diabetes

[@arnaldojansencarino5391]

sorry to hear than.

[@CSKweon]

'won't result to' u already had one. sry m8

[@saeadborji1464]

hahaha very punny

[@floodstreet2961]

Jake Lamb prick

[@haninditohaidarsatrio7393]

'Catbacks. Resonator. Straight Pipe. Today we're not talking about any of those things.' What a twist XD

[@andrijastefanovic726]

Hanindito Haidar *top 10 anime plot twists*

[@randy438]

To be honest, this is my favorite part of Donut, sorry James

[@JoeIsCrazyWillman]

Learning stuff is great!

[@maukka4229]

@@JoeIsCrazyWillman My favourite donut show is definitely up to speed

[@saisathvikkata3930]

You know that obviously wheelhouse is the best

[@iamraylin4you]

墨西哥入境

[@haydenclark8290]

i miss this dude

[@quillmaurer6563]

"Designers knew what they were doing, and unless you REALLY know what you're doing any modifying will make it worse" "The environment matters because we don't want to poison everyone, make smog, and cause acid rain." Two truths you'll rarely hear from car guys. These guys make amazing videos while being knowledgeable, down-to-earth, and wise. Not the usual "Get rid of your cat to get +15hp, bro!" This makes me a hypocrite though as I drive a '73 VW Bug with terrible emissions (no cat obviously, they didn't put them on back then) and I've modified the crap out of it, including electronic fuel injection. I've had thoughts of, once I get that fuel injection system working well and actually tuned right, maybe after putting a turbo on it, trying to incorporate a catalytic converter into the exhaust, just to see if I could do it and make it work right. Would be a crowded exhaust system, having turbo, cat, and muffler all packed in under the back end of the car as the engine is in the back. Don't have the money or fabrication skills to do something like that ... yet...

[@TheA53ford]

Quill Maurer turbo bug? Nice idea man, wish you luck on that. I'm into making sleepers out of cars myself. Hell my daily is going through that as we speak.

[@quillmaurer6563]

Thanks, I'll need it! The bug is my daily, but I don't see why I can't have a daily turbo bug.

[@onometre]

it's so refershing to see a car video that doesn't take a straight up hateful view to any kind of environmentalism. WE GOTTA BREATHE GUYS

[@TheA53ford]

Quill Maurer I can highly agree there. My daily build is my coupe Accord (2002 model). I've got a better intake on it but I'm working on some other parts like getting a SOHC core and shipping it to Bishimoto for a stage 2 or 3 build.

[@lsswappedcessna]

I hope you have a spare bank account lying around. The reason us car guys like to rip them out isn't that we hate the environment, it's that they're more expensive than an engine! you can get a used 5.3 Vortec V8 for around $2,000, which is damn good for such a flexible and reliable (in my experience) engine, being capable of powering a full-size SUV and hammering down like any other vehicle. Honestly, I'd take the Vortec over a cat, simply because it would be worth two grand. An expertly machined chunk of precious metal isn't really interesting, unless it'll make the engine sound better and perform better without me having to sell anything.

[@florismesu5727]

1:55 the catalytic converter in a car indeed has rhodium. The element in the picture however is rubidium (Rb). Should be Rh. Rubidium would however look spectacular when put in an exhaust pipe, as it reacts violently with water and oxygen.

[@calebjimmysmith]

Good catch! I also noticed this mismatch and was confused. Thanks for clarifying.

[@lexus_offroad_adventures]

Some teacher was probably showing these videos in class until 0:41 happened 😂

[@barber4045]

Daniel G He says “you suck” not f**k. But I can see what u mean when he says sh*t

[@MurphyFamily0210]

I long for the days when we get over this infantile obsession with curse words. Not using them, mind you, but obsessing over when they're used.

[@AnthonyTrifoglio]

College professors don't care

[@RussianBot69420]

Hey, at least they censored the second fuck

[@jasonl5589]

I died at this

[@ParadoxdesignsOrg]

The Catalytic Converter in my 240sx overheated and grenaded itself out the back of my 3" exhaust. That was kinda cool.

[@savagesock3598]

Well I'm sure it was a learning experience lmao

[@Kevinb1821]

Catalytic Converters really are one of the best improvements for cars ever. Other great advancements that nobody talks about thought is variable valve timing. Without it we’d be stuck still driving seriously underpowered cars to this day like in the 80s. Thanks to variable valve timing. We get great fuel efficiency when we’re just putting around then when we want to stomp on it. We also get awesome power. Another great advancement is fuel injectors. People say it’s more complex but I think it’s easier to work on than a carb. The computer does all the work. All you gotta do is pop the old fuel injector out and plop in a new one. Also I think coil packs are way easier to work on even if it’s more complex to make. Also an idiot can’t wire a coil pack the wrong way like my friend did with his distributor cap. He just put the spark plug wire back any which way and ducking up his car.

[@jordan2735]

except meth heads are willing to shoot you and your kids in the head so they can cut it off and sell it for $100...yeah great contribution to society.

[@vegetossgss1114]

I have a new car model (about 2017) working on diesel and a semi-open garage (I mean there is a ceiling that covers two-thirds of the car but not all the car, three walls but there is no door in the entry, and instead 2,5 meters of fresh air). Can carbon monoxide still be dangerous if the car's motor remains on, or is it safe even if I forget to put it off and stay inside the garage??

[@gremlincc]

Damn I feel smart now

[@AndreiT04]

Curtis Campbell hi from french

[@daverichmond3228]

You look smart!

[@minimumdorifto6595]

me too thanks

[@Adrianlovesmusic]

bye bye ...i just forgot steven hawkings name lol

[@met_big_kawaii4999]

Curtis Campbell there is a mistake in the video, carbon monoxide does *NOT* deplete the ozone layer

[@romainj9520]

damn good thing you finally made a video on those catholic converters, they're all over the place ringing my door every tuesday with their bible and stuff smh

[@lsswappedcessna]

"Sorry friend, I don't want to become a child molester."

[@reallyhappenings5597]

Romain Joubert. No they're not.

[@kirknay]

That ain't catholic, that's either JW or mormon.

[@reallyhappenings5597]

Romain, your lame joke shows how little you know of Catholics. They don't go around door-to-door, and as a group actually haven't done much evangelizing in centuries.

[@joonasd7]

@@reallyhappenings5597 No one cares

[@narlycharley]

This is such a great series of videos. Funny, witty, easy to understand, and FULL of GREAT and useful information. Keep it up guys!

[@ricewolf9750]

This entire youtube channel helped me pass my ASVAB for the army with flying colors, specifically the mechanic section of the exam.

[@barber4045]

I love these vids SO much because I learn something new with every one of them. But I’m still waiting for that Supercharger-down-to-the-atom vid •_• xD

[@ahmadkhatab6527]

Carlos Barberena i want to see how is antilag made 😂

[@kianduesing]

Haha, yupp me too XD

[@barber4045]

LetThe HateFlow Hahaha 😂

[@GETUPANDGO]

For sure, same here--if only school was this much fun

[@barber4045]

GETUP AND GO Seriously, I would be at school right now if Science class was Science Garage lol

[@augustsawzak5401]

1:52 Rb is rubidium.

[@johnkayne5044]

And Rhodium (Rh) is used in catalytic converters!

[@augustsawzak5401]

John Kayne yup, he says it right later on though.

[@daivdormaza1987]

Lol I was going to say... all chemists cringed at that moment

[@aidan5077]

Rubidium would be very bad to have in your cat lol, exploding when the hydrocarbons are oxidized and water is created

[@SunSunSunn]

This is literally the best series out on KZbin! I study at Stanford University and this is probably more useful than anything I’ve learned from there.

[@Gr33kNinja]

This show is great. I’m okay if you guys get into more technical stuff dealing with the engine because I want to start working on my car soon. I really like this format.

[@dougarnold]

I wish they did a video comparison of stock cats vs. high flow cats vs. straight pipe. Maybe even cut open a hfc to see the cells.

[@cesarcarmona9361]

dougarnold maybe engine masters should do that since they actually dyno test

[@FlamingoVlogs]

dougarnold maybe a video on spacers/defouler

[@DericCribbs]

People need to learn how obd2 works! This will help people understand why they don't "need" a special dealership computer to work on their car😲

[@concordsst]

Deric Cribbs unless it's a VW/Audi in which case they give two different codes, one generic obd2 that doesn't help, and one extremely specific code that requires dealer software to read

[@DericCribbs]

concordsst this is what I'm talking about. You're referring to vcds and there are open source mobile software for them also, but you'd have to be interested in learning more about software to make it work. They could mention the brands that have these proprietary systems so we could make our own choices about vehicle service.

[@ZambonieDude]

that would be great actually.. some things are quite confusing.

[@jackgrimsinn]

Donut media has a video on this!

[@rebirthedservant]

Your right they don't, but not every jackleg can diagnose one properly. Being able to scan it and being able to fix it are 2 different things.

[@sonipwn]

I love this guy and I love how he explains everything while sticking to the point

[@karloavera]

Thanks for explaining things in a way that's easy to understand!

[@VehicleVirals]

Killer episode, can't wait for the next one

[@cortneyjackson1739]

Yes ma’am

[@cortneyjackson1739]

Yes

[@cortneyjackson1739]

Yes ma’am

[@raremushroom78]

This aged like fine milk

[@kashvirshah3408]

@@cortneyjackson1739 sir pls leave these comments

[@lleytonalbertini351]

guess what guys its Thursday tomorrow and you know what that means ..... UP TO SPEEEEEEEEEEEEEEEEDDDDDDD

[@OhighOSkater]

Lleyton Albertini Need that!

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Neu neu neu neu neu noo neu noo neu noo neu noo neu!

[@austin_s1974]

Lleyton Albertini RAMCHARGERS

[@daniellamendoza4914]

Lleyton Albertini hell yeah today is Thursday..... a year later 🤣🤣🤣

[@rubycolt4664]

@@daniellamendoza4914 yep a year later and just as the person said it's thursday tomorrow (for me)

[@daleanderson1727]

Simple, straightforward. Well done. You have earned another subscriber.

[@actng]

this is really informative i like how you guys actually do research and produce educational videos

[@DoomFinger511]

God I love this series. This new show and Up To Speed will keep me a long time active subscriber.

[@AidanTenud]

Top ten comments before disaster

[@flamingbeancurd6458]

Do carburetors next.

[@DaBrute]

Yes!! I have no clue how those things work

[@theresaoakes9387]

+DaBrute omg yes. I get the jets, I don't understand the floats. just that they keep things from starting.

[@ancientapparition1638]

I think they did that already

[@coal2710]

Carburators are not used anymore. Now, there are Electronic Fuel Injection(EFI) systems that are connected to the cars' Engine Control Unit(ECU).

[@AmericanThunder]

@@coal2710 Yes, they are used. And a lot. In fact, I just rebuilt one yesterday. A 4100 series 1959 Autolite/Ford 4 barrel. If they weren't still used today, summit racing, jegs, etc, wouldn't be selling so many of them. lol In a performance comparison between a BG Race Demon carburetor vs an electronic fuel injection, both installed on a base test engine, the Race Demon carburetor outperformed the fuel injection not only in horsepower, but also in low end torque. Fuel injection is handy if you can't build your own engines/tune your own carbs, etc. But otherwise, it is inferior in terms of performance on naturally aspirated engines.

[@Malik-jt8hi]

You guys are so awesome. I'd give up watching all my subscription channels to get constant vids by you guys or meet you and Humphrey. I loved cars since the first transformers movies as a kid. Thanks so much for teaching a newbie like me about everything about cars!

[@ryanclaffey3526]

Thanks for doing this im so sick of everyone thinking being catless is cool!

[@dinisfigueira9918]

Do we get a mechanic's degree with this video? :D

[@andreyiscool]

This show is always awesome!

[@TheRnwood]

Another fun informative video!!!!! Thanks for the journey!!!!

[@shukriaidil7505]

Thanks for the explaination dude. I learnt something today

[@hf2848]

*"don't tell my wife I took the catalytic converter off her car"*

[@CEOMBE870]

😂😂😂

[@sirlancenolasco3552]

Yaaaay!!! Y'all did catalytic converter! I love this channel. So entertaining. Also 3:25 - 3:26 I thought you were about to sing "We will, we will ROCK YOU!"

[@adamc7987]

Sirlance Nolasco Remix away! Ask Schmoyoho kzbin.info

[@bakasama509]

The cut-it-open part was a great surprise! Love seeing the chambers.. makes so much sense Bravo!🎉

[@jefferylara5775]

Never get tired of watching this guy talk tbh. Awesome!

[@WarriorsPhoto]

You're now my favorite presenter for Donut Media. You are funny, witty, and highly entertaining. Did you get training on this type of media presentation?

[@nitrosalt52]

“Don’t tell my wife I took the catalytic converter off the car” that smile sold it oh my lord it was perfect 😂

[@basimnaqvi2789]

Wow! This was brilliantly explained!

[@emmanueljoseph506]

Straightforward, nicely presented and informative , Witty.Thank you

[@Ledfndr]

Modern cats don't hurt performance, you can have your power and be clean too, no excuses anymore Honda bois.

[@lsswappedcessna]

cost? bloody two and a half grand for a chunk of metal!

[@F22C1]

Removing that shit is good for 20hp in my case. No one died because of a catless car. Get a grip. 😂

[@Overfl00d]

Le Enderman And now you fail smog checks and can't legally drive.

[@oscar721x8]

Even if cats hurts performance, I will still leave them on.

[@ZambonieDude]

Le Enderman If everyone had the same mindset as you we'd all be dead by now.

[@TheMilesYiengst]

Rb is Rubidium, not Rhodium. Rhodium is Rh I'm a chemist that tests for metals. :)

[@balance5216]

No one asked 😂

[@TheMilesYiengst]

@@balance5216 lol. That was 2 years ago bruh.

[@hailcaesar6185]

I asked, you got a problem?

[@evanclarke6496]

Don't worry, as a fellow chemist I was also extremely bothered

[@mrninjadude100]

Great host, great editing, and great scripts. Love the vidoes!

[@RingoFreakingStarr]

This is the best series on KZbin.

[@lawrencemonro2568]

I’m probably one of the fewMotoring enthusiast who isn’t a fan of guys remove there cats for the extra 1-5hp and in doing so their impact on the environment is so much greater

[@JoeIsCrazyWillman]

I'm another. I actually installed dual Magnaflow cats (my truck originally came with only 1) since I have a full true dual exhaust, and I lost 0 noticable performance going from 0 cats before to 2 on the same exact exhaust setup. All I "lost" was a stinky exhaust, a couple dB inside the cab (particularly at idle) and a few less dB outside the truck. That's it.

[@Keithjustkeithwastaken]

shame that it wont make a difference at all in the long run becuase like 90% of emissions are made by factories and big companies

[@gredystar8333]

@@Keithjustkeithwastaken While factories and boats do make up the majority of our global emissions, those emissions will not directly affect you as much as the local sources of pollution in your area. Factories pollute the atmosphere, cars without cats directly poison you and everyone around them depositing CO and unreacted hydrocarbons directly in your lungs

[@KayoMichiels]

Unless..... you were Honda and invented an engine (CVCC) that didn't need a catalytic converter, and later built a small car around it.... and BAM!!!: The Honda Civic!!!

[@LouisSubearth]

MK3424 CVCC was effective, and it was insanely complicated. Swiss watches are child's play next to CVCC. That's why Honda later switched to conventional catalytic converters later on.

[@patx35]

It was amazing that Honda passed emissions testing on a vehicle with a carburetor and NO catalytic converter, but it was complicated AF.

[@devinwilliams3489]

It was good enough at the time, but stricter laws meant it was not, so a cat still became required

[@KINGMUFASA]

Very good video. Thank you! I really appreciate your sense of humour🤴

[@123kgroves1]

Great video. Learned a lot. Love the humor. Keep it up guys! :)

[@cesarcintron87]

You just became my hero you're a genius thank you for explaining this everyone needs to stop the madness keep that shitt in your car

[@Keithjustkeithwastaken]

no

[@DucatiDiaries]

"You see what I did there? Catalytic converter." ROFL

[@bonboniya_]

Just found this guy's channel and I LOVE IT! Bart for president 😄

[@sayala909]

This was very well explained. i dont know a thing about cars but i definitely learned something today, tysm!!

[@firebird188]

Tell this to the people that watch the Haggard Garage.

[@GETUPANDGO]

It's like Bill Nye for cars

[@CoelhoSports]

only this guy seems to know what he's talking about

[@lsswappedcessna]

"Tires are on a spectrum."

[@GETUPANDGO]

Precisely

[@progmanmike]

Except there’s no talk about sex junk

[@rst812]

Thanks for the easy explanation!

[@lindakheswa4955]

Awesome video mate! Thank you so much!

[@MrChinofig]

Hi flow cat if you want loud exhaust magic 👍🏼

[@FoggamingMc]

Bill nye the car guy

[@lsswappedcessna]

"Transmissions are on a spectrum"

[@timfitzgerald109]

Very informative with great humour .

[@juliamedeiros696]

Amazing video! Thank you so much, helped me revise for my As chemistry exams.

[@matejblaha6870]

carburetor next?

[@VictorEstrada]

I really like how he cares about the environment. Hate guys going "catless" just because it's cheaper and "sounds better". High performance will sound just as good and perform just as well as catless, only downside is that it's a bit more expensive. But it is very well worth it for the only planet we have

[@Keithjustkeithwastaken]

not its not because it doesn't matter the emission problems start at factories not at the people

[@OmniversalInsect]

@@Keithjustkeithwastaken Normally yes but there are a lot of cars and each car would emit a considerable amount of these gases over time

[@theunhingedgamer3762]

​​@@OmniversalInsect as if it matters tbh factories cause far more pollution in 5 minutes than a car does the whole "love our planet" nonsense is a bit rich given people didn't care in the slightest until 3 years ago and even now the whole green movement is idiocy at its best because people think gas powered cars are bad but they ignore the past studies on what batteries do to the environment

[@farzadizaddoustdar4259]

Donut and Carfection are taking over. Great stuff guys.

[@furqanprosto3393]

Knew Catalytic converter since school , but editing as expected so good that enjoyed watching it❤️ Very good work Donut Media ❤️ keep it up 💪🏻😊

[@darthpotassiums1fan20]

How do hybrid systems like in the Porsche 919 LMP1 car work? How do they turn the heat from the exhaust into energy they can use?

[@Donut]

Great question! We'll have to do that!

[@mohammednurul9380]

I thought only the Ferrari leferrari did that, it's called KERS by the way.

[@gameclips5482]

1:07 that guy tho

[@friendoftellus5741]

Very educational. Thank you !

[@mazharsoufi5270]

very very helpful!! thanks dude

[@Pwnsweet]

"Let's cut it open!" in the kitchen....

[@St0RM33]

How do cats work? MEOW MEOW of course!

[@silasfox]

You are so amazing at being engaging it's hilarious! I love this.

[@krannification]

Best series on donut media yet!

[@_baller]

Oh i thought there was a dead cat in the tubing.. thanks

[@adhambashnak315]

Do up to speed video about volvo plz

[@cutemuzzu3081]

Awasome Video ! Excellent

[@danniiliasoff2732]

Absolute great Video. Love the Humor and the facts ✌️🙂

[@Firesite8514]

This is why I really don’t like the idea of people removing their cat’s it seems so selfish to damage everyone’s environment for a few more horsepower. If that.

[@the0r3ooo65]

What do cats have to do with this video?

[@fossilfountain]

@@the0r3ooo65I almost took the bait 😂

[@sandromicic6102]

Catbacks Resonator Straight pipe RAMCHARGERS

[@austin_s1974]

Sandro Mičić RAMCHARGERS🙌

[@armanitheshortkidd5066]

Ramchargers🙌 thx james

[@dayofthedaleks1523]

R A M C H A R G E R S 🙌

[@richardjimenez7394]

Thanks i having problems with my Suzuki Grand Vitra 2000 passing smog. I have taken to auto repairs shops and all of them didn’t know what they were doing I think. Until I got on utube doing my research on Suzuki Grand Vitra and now my Chevy Silverado is having the same problem. Again thank you for your share.

[@pullupbruh5810]

This is literally the first time ive seen this guy and within 30 seconds of watching i wanted to subscribe

[@snaaail]

Anyone else use to think it was called a Cadillac Converter? No? Just me?

[@rogehmarbi]

No, but I used to think it was actually called cataract converter

[@theresaoakes9387]

when your car gets a p0420 code....(Darth Vader voice)*NOOOOOOOOOOOOOOOOOOO*!

[@lsswappedcessna]

P0420 is just O2 sensor! No two thousand dollars out of pocket for you. Maybe a few hundred because sensors are a bit much, but not two grand!

[@ralphnapierii1184]

@@lsswappedcessna nope. P0420 is the O2 sensor telling you the cat isn't working. Throwing a couple hundred at a sensor only lightens your bank account.

[@duncanotema]

Man...best lecture I ever had

[@nomimalone7520]

This is my favorite series on donut.

[@oromis995]

Dude you gotta normalize the audio in your videos, these spikes blew my eardrums out

[@I5ZQ8]

Take them off for more power.

[@finnkennedy2401]

I5ZQ8 no

[@seriousgoat76]

You can get fined for not having one.

[@charliefoxtrot4154]

Its MAGIC not where i live

[@lordrefrigeratorintercoole288]

I5ZQ8 get a sport catalyst, u get more hp. numnuts.

[@calebtester1327]

Straight pipe is life. No emissions where I live.

[@hrevyaga82]

Great explanation and dissection science NUT.

[@docmorrell]

I miss Science Garage #BringBackBart

[@JustaYeomanBowman]

If I don’t have a cat, I’ll go faster. If I go faster, my car won’t run as long. Therefore, speeding is better for the environment. 🌈The more you know🌈

[@kusugara]

Drag

[@derrickwillie4449]

Oh my gosh, your videos are so annoying. I can understand the enthusiasm and graphics but cranking the volume up is messed up.

[@MrJosue106]

This show takes me back to my elementary days. It’s like a fun class

[@poorvikadineshkumar1196]

Superb explanation

[@davidesquer7776]

Wow really in-depth video

[@Oxxyjoe]

Super cool video. you have catalyzed my conversion

[@grantpernice8401]

You guys are really helping me out with my science project on vehicle emissions xD

[@nodnod465]

Saw this video on Facebook, I then immediately opened my KZbin app and subbed; great content!

[@nodnod465]

Now time to binge.

[@pessimiskate]

AWESOME VIDEO!!

[@richardjones4259]

Great video!

[@musicwithj1759]

This channel is the only reason I’m the best in my auto class.

[@MrDatrandomguy]

Love it! Keep it up