JTJerryls400

I thinking about remove my cats and put in that place straight pipes.
I have two questions:
First: will that mod create any power that I can feel???
Second: make any trouble codes ???(I ask because I saw that there are oxygen sensor before cat but after too).
Thanks for help
Jerry
Sorry for my English

wwest

Your engine control ecu firmware will get VERY confused, diagnostic codes will be MINOR problem.

LOTC

Removed my last two cats, no problems. Just a nice rumble and a little bit of better throttle response and more power at the top end.

JTJerryls400

my lex has only two cats, just after manifolds one on the left and one on the right side
Jerry

healerhand

I think "Check Engine" will go on, but i am not sure. If you remove CAT what happen to O2 sensor?

wwest

The check engine may not go on right away, but it will eventually.

But by the time it does you may have already done some serious damage. Say the engine air/fuel ratio running predominantly, or maybe only within certain performance levels, too lean.

I don't actually know how the firmware is "constructed" but those oxygen sensors are there for a reason, and you can bet that the engine ECU firmware makes use of the differential sensor reading of the "before" sensor vs the "after" sensor to continuously adjust, correct, the engine's air/fuel mixture ratio.

Without the "Cat" in the loop, contributing its "correction" factor to the exhaust gas outflow, you can bet that the air/fuel mixture lookup table is outside the map.

JTJerryls400

I removet all my cat in all my cars before but they do not have o2 sensor AFTER the cat.

Lvangundy

Just remove the 2 resonators second from the rear..or i dunno hah