AWR header re-make

[perfworks]

so we just have to have an O2 sensor before a cat and one after? so in theory we can still remove the first cat and put the O2 sensors around the 2nd cat? would moving the O2 sensors back make the burn richer or leaner?

later

You are not effecting the burn by moving the placement of the sensors. What happens is that by moving the placement of the cat you are lowering its light off temp. The farther away it is from the energy source the less efficient it works to chemically react with the molecules of CO and HC. The first O2 will still see an A/F ratio as accurately as before but the efficiency the second O2 sees for the cat will vary. But again a properly tuned vehicle With one cat in line should have no issues with high emissions output.