Originally Posted by killerkanadian
On the note of Downstream 02 Sensors. Eurocharged has figured out in their tunes to make them irrelevant and not read a check engine light.
As far as i am concerned, keep the upsteam O2 sensors and delete the downsteam.
secondary cats are irrelevent anyway. i deleted mine without any ecu mods to cover it and never had a cel. deleted the resonator also and no cel. as long as the primary O2 sensor is upstream of the cats you can put them virtually anywere