Due to clearance issues, I had to move my O2 sensors back about 12" from the header collector.

I know they like it more forward if possible, but they seem to do ok way back at the tailpipe when you're on the dyno.

So is the preferred forward mounting an emissions thing (getting the sensor to warm up sooner to go into closed loop) or is it a lag issue (since it takes a few microseconds longer to move 12", maybe the ECU can't react as fast)?

Either way, will 12" make a difference?

 

I doubt it..

I just dont like to have mine after the collector ...

just so if I have a leak my car wont run like assbag

 

How is assbaggishness prevented by being in the collector? Isn't a leak a leak?

 

Never mind, I get it now... a collector leak, which is common, won't necessarily affect the sensor if the sensor is upstream of the collector, but if its downstream, it will for sure.

 

exactly ......