Honda Car Forum

Will my oxygen sensor be affected if I put in a High flow cat in my honda Civic si?

It should actually be fine. what would affect it however is if you do a new exhaust system and take out the cat altogether, running it straight back. while this would increase the flow substantially, it would probably throw the O2 sensor. I read something about spacing your sensors though to prevent this but i dont know anything about that.

It shouldn't.

u didn't state the year ...but ..there's a good chance that this will affect the ses light....is your o-sensor in the cat? if it is its a definite yes ...if its downstream the you could be alright .. there are many cat manufactures and like any other product...some are better than others.......we install hy-po exhaust systems everyday...and some types have given customers fits over this same issue...we've tried the spacing method (with limited success) we understand that they make a wiring kit for the o2s to take care of this issue ...and have ordered them but as of this week we haven't received any.......so their funtionality is unknown to us at this time

O2 sensor are temp sensitive - not flow sensitive.But you always check with the high flow cat converter seller to check.Good Luck...