Smog and cat

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.


Slightly Disturbed
Feb 3, 2006
Does anyone happen to know what the difference in inlet and outlet temp should be on the cat. I know outlet should be higher, but by how much?

Infrared thermometer said inlet 417 deg, and outlet was 485deg, so roughly a 70 deg difference. It that enough?

Any advice is appreciated.

Dynosoar :zilla:
Hi Tinker,

The only temp mentioned in the emissions manual is a temp of 1,445 deg F as the temp when the AI system will divert air away from the cat.

Dynosoar :zilla:
200 degrees is what I've heard. Also I've looked in the FSM, emissions manual, and Haynes and I couldn't find anything.
I guess it depends on how clean the engine is running on the temperature difference. I would measure mine and post it if I had a IR thermometer. This was from the link below.

For every 1% of CO in the exhaust gas stream the exhaust gas temperature will rise by 212 F
The low temps were taken at idle after start up I did not drive it around first. I was just trying to see if the was a difference from the inlet to the outlet. I will drive it and warm it up properly and report back.


Users who are viewing this thread

Top Bottom