- Catbacks, resonators, straight pipe.
Today, we're not talking about any of those things.
We're talking about the catalytic converter.
A catalytic converter is designed
to reduce harmful emissions.
(coughing)
In another video, we talked about how gasoline
is made up of hydrocarbons.
If everything goes perfectly, all of the hydrogens
and all of the carbons combine with all of the oxygen
to give us carbon dioxide and water.
No big whoops.
But the combustion in an engine isn't perfect.
Some of the reactions are incomplete.
And because of the heat in the engine,
we create some molecules that don't normally occur.
So one thing we get is carbon monoxide.
It's bad.
It gets rid of the ozone layer.
- Shit
- And it's also poisonous.
- (beep)
- The heat of the combustion means that some of the
nitrogen, because it's 78% of the air, gets jacked up
and bonds with oxygen in any number of combinations.
And that's also bad for your health,
and it makes our rain acidic.
It's just bad news.
- Hey, that's tough.
- And lastly, if some fuel isn't burnt,
those harmful hydrocarbons get shot out the tailpipe too.
(engine revs)
Catalytic converters are designed to reduce
all three of these emissions.
And the first one was patented by French
chemical engineer, Eugene Houdry in 1950.
We talked a little bit about catalysts in our video
on tires, and you can check that out right here.
Most basically, a catalyst is something
that helps a reaction take place.
The things in here act as a catalyst
to help convert your emissions to make them safer.
You see what I did there?
(maniacal laughing)
Catalytic converter.
Alright, so what's in here?
There's ceramic.
That doesn't react with anything, but it gets super hot,
and it stays super hot so the reactions can happen.
If you're going for an emissions test,
make sure your catalytic converter's hot.
Next, there's rare metals, platinum, palladium,
and rhodium that react with the emissions.
They're each worth about $30 a gram, and there's between
three and seven grams of them in a catalytic converter.
So that's why people steal them.
But, the metal in a converter is worth about
as much as a catalytic converter, so don't be a jerk.
First is a reduction catalyst.
Platinum and rhodium pull oxygen off the nitrogen atoms
so the nitrogen gets shot out as benign N2,
the way it came in in the first place.
The second stage is an oxidation catalyst.
Platinum and palladium use the oxygen molecules
in the exhaust, and the freed up oxygen
from the first stage in two ways.
First, it helps bind them to the carbon monoxide
to get CO2, the same stuff you breathe out.
And second, this stage converter will oxidize
any unburnt hydrocarbons as they pass through.
Some cars have a pre cat closer to the engine.
It's still a catalytic converter, but
because it's so close, it gets hotter quicker
and it does a super duper job at converting,
but because it gets hotter, it can wear out faster.
The oxygen sensor before the cat lets your car know
if there's enough oxygen burning the fuel in the engine.
If too many hydrocarbons come through,
a computer will adjust to mix accordingly.
Another oxygen sensor after the cat let's your engine know
if it's pulling in enough oxygen
to complete the reaction in the converter.
It's all super high tech and it happens super fast.
So do catalytic converters rob you of horsepower?
(gasping)
Before we answer that, let's cut it open.
(sawing)
(metal clanging)
(pounding)
(sawing)
Inside, you can see the honeycomb, and
if I hadn't beaten the crap out of it
with that angle grinder, we'd have nice clear channels.
And you can still see light through it.
(whistling music)
(air whistling)
This is a good cat.
(cat meowing)
These chambers are designed to have the
most surface area possible to make the reactions happen.
They're also designed to affect the exhaust flow
as minimally as possible.
Some brain trust cut these honeycombs out
to open up the airflow, so that when they get inspected,
it looks like they still got one.
But cutting these out means the air is suddenly sitting
in a big hollow chamber, instead of shooting
straight down a streamlined pipe.
Cars are an intricate system of computers and tuning,
and unless you're skilled at this type of thing,
just ripping out a part of your exhaust,
that can seriously damage your car.
Modern catalytic converters are designed to be efficient.
There's even performance catalytic converters
that have been shown to help improve horsepower.
The main thing is that catalytic converters work.
American emission pollutants have
dropped an average of over 70%.
That's a big deal.
And when you look at pictures of any major city,
before and after we started using them,
it's equally as easy to argue that the catalytic converter
is one of the most important
advancements in automotive history.
Subscribe to Donut.
If you liked watching this video, please share us.
The more we grow, the more cool stuff we can do for you.
Follow me on Instagram @bidsbarto.
Follow Donut on Instagram @DonutMedia.
If you wanna have a bad ass car, check out Tony's video
on performance mods that actually work.
You like speed?
Check out this video on F1.
Don't tell my wife I took the
catalytic converter off the car.