A header is designed to remove exahust gasses from an engine more efficiently through its scavenging properties. In addition, more heat would be transferred through the header and the rest of the exhaust system as the exhaust is evacuated. To keep underhood temps down, a header can be coated (e.g., JetHot, HPCoatings, etc.). Since the heat is kept in the header, additional heat is transferred through the exhaust.

All that being said, would the additional heat of a coated header equate to the life of a catalytic converted being shortened over time? The additional heat tranferred through the exhaust on an n/a car would be nowhere near as hot as that from a n f/i car, but the principle remains the same.

I know using a test pipe and taking the cat out of the equation would be the best route to go, but I don't want to crawl under the car and swap out parts for emissions testing year after year. On the flip side, I also don't want to destroy my OEM cat prematurely and have to replace it since they are a bit pricey.

 

An aftermarket header should not change the life of your stock cat, it will be seeing aprox. the same heat ranges.

 

to tell you the truth the catalytic converter can handle high heat temperaturs.

When i was doing research on catalytic converters the Standard 1000CPSI which is your regular every day cat, can take EGT temps up to 3000-5000deg depending ou make and construction.

the Mettalic based cats which is highly reccomended for big butbocharged applications can do 7000-9000deg F. these cats are designed to take allot of heat. they are most efficient when they are hotter the only thing that will case problems or flow issues is when the temp is exceeded. the core will actually swell up and cause a bottle neck.

High flow cats are around 100-500cpsi core construction and the metalic version proves to be the best for high horsepower application.