crolldaddy

in using the bosch 13111 o2s, should they be used for the rear or all four??seeing is i have emissions to pass this year at inspection time.

TheBlurLS1

iTrader: (8)

Most people use them on the front, and only with headers. Do you have headers? Give us some more info on your car. You don't even need rear O2's at all as long as you're not throwing the SES light.

If your exhaust is modified, you will probably not even need to worry about using rear O2's at all. They will most likely set off the SES even if you do run cats.