Quote:
Originally Posted by B-R-Z
Your response is very descriptive thanks
@ EpicNameBro : How different is the secondary cat in terms of functionality? I'm guessing relocating the sensors around the secondary is better than having both sensors reading exhaust gas coming straight from the engine, no? I'd prefer to wait until warranty expires before tuning.
I've been running my uel header for a full tank of gas now and I've had slightly better mpg with no cel yet. |
They reduce emissions during the start up phase before the primary gets to temperature... So with that being said the secondary cat has no role whatsoever in O2 sensor function or emission control feedback function. The primary determines if the car is running too lean or rich and adjust as such. Going off the second cat gives a false reading which depending on your set up may be doing more harm than good...