Dual O2 sensors

[thechuckster]

a factory car (except something fairly new) is only going into close-loop during mild engine operation (e.g. cruise, warm idle, mild accell) so the engine isn't under much load.

This means cooler gas temps and slower gas speeds - but with heated O2 sensors, close position to the head isn't all that essential. So ... unless you're trying to compensate for individual injection events (when timing of the sense signal and/or placement of the sensor comes into play) having two does seem rather redundant.

Also, the stock items are most-likely narrow band sensors so they're limited in operation functionality.


i've seen headers on race cars with bungs in each runner - but in the race cars all of these were blanked off suggesting their purpose was limited to race-preparation tuning work.


edit: why 2? redunandcy to cope with limited maintenance and wide range of fuel abuse? the engine can control timing on each bank seperately? maybe the factory ECU can tweak each bank seperately when on cruise?

[JustCallMeOrlando]

His question was related to why do they run one on each side, as opposide to just one on one side (in the same position), and nothing on the other.

Not why don't they run one at the final collector.

This man has hit the nail on the head.