Catalytic converters are emissions equipment required for street legal vehicles made in the last 50 or so years. They’re a simple design that uses complex chemistry to clean up the waste gasses leftover after the combustion process. Noxious exhaust gasses enter the catalytic converter and flow through a honeycomb design that performs reduction and oxidation chemical reactions, incinerating gases before they leave the exhaust. The International Platinum Group Metals Association says this quick process reduces 90% of a vehicle’s harmful tailpipe emissions, so cats really are a good thing
HOW THE CATALYTIC CONVERTER WORKS
Catalytic converters do fail eventually, usually due to impact damage or excessive fuel contaminating the internal catalyst surface. Modern designs of the last 25+ years include catalytic converters in PCM calculations, so “I’m gutting emissions for more power” in your modern Camaro actually means decreased performance.
WHY CATALYTIC CONVERTERS FAIL, AND WARNING SIGNS
A failed cat will show common symptoms of increased gas consumption, poor engine performance, a check engine light, failed emissions test, a sulfur smell (“rotten eggs”), and possibly a rattling sound from the cat while driving.
That last one means the cat has broken apart internally, likely causing a clog in the exhaust pipe as well as generating a massive amount of heat. Mainly, you’ll notice terrible performance (imagine driving through wet sand), due to the increase in back pressure and exhaust restriction. Don’t drive like this, as it is dangerous and will further damage your engine.
COST TO REPLACE CATALYTIC CONVERTER
If you’re quickly Googling how much it costs to replace a catalytic converter, you’re probably going to be dismayed by what you find. Some price aggregate sites show catalytic converter replacement costs as high as $2,000 or even $3,000 in some modern vehicles. Ouch. However, you should ask a mechanic you trust for a second opinion.
WHY THE PRICE DIFFERENCE IN CATALYTIC CONVERTERS?
If catalytic converters all do the same thing, why aren’t they all roughly the same price?
“There is a reason for the difference in price,” said Rakowski. “Maybe the dealership quoted someone $2,000 but the exhaust place said they would do it for $300. So now the consumer thinks they’re getting screwed and overpaying by $1700.”
“It’s not about someone wanting to make an additional $1700 off you. What they don’t understand is, if the inside of a catalytic converter got cut open, the precious metals in the cheap one will cover maybe 10 square feet, while the more expensive one will cover 60 square feet.” The massive price discrepancy is explained by what sounds like a motivational quote: “It’s what’s inside that makes the difference.”
You can’t see the inside, but there are a few tips to score a quality cat. You will want a catalytic converter from a reputable brand. If you don’t know exhaust manufacturers offhand, you can check reviews online, or look at their warranty. Emissions equipment has a federally mandated warranty, so don’t purchase one from a janky website offering $50 cats, because it’ll lack the warranty and the required metals.
Rakowski said that in addition to the proper amount of the precious metals, the higher price is also due to superior and more durable construction techniques, meaning the part will last for many years on the road. It’s also due to newer, reduced-emissions designs incorporating the catalytic converter into the exhaust manifold. Rakowski said he has seen examples where the budget converters available at cheapo exhaust shops don’t even last a month.
“The customer might still have a check engine light if they put a crap converter on,” he said. “It’s a shame, but that’s what happens when people only look at dollars instead of what is right for their car.”