O2 Sensor Location

[MikeHolt]

I’m swapping out my Innovate O2 system to Zeitronix. I read somewhere that O2 sensors should be a minimum of 18” from the Exhaust Manifold.

For those of you with the MK II or older cars with J pipes. Where did you locate your sensors?

Right now, mine are mounted vertically in the bend of the J pipe. But, I’m thinking of moving them to the very end of the J pipe. It’s not a huge amount of difference. Just wondering if I’m wasting my time or if I should relocate them into the side pipes themselves.

Thoughts?

[Bob Cowan]

It depends on the sensor. A 3 wire sensor is not self heating. So it needs to be fairly close to the head to get hot enough to work properly.

A 5 wire sensor is self heating. It can go almost anywhere. With headers, the collector is the best place. Think of a J pipe as a collector. If yours is working properly now, leave it alone. There's no need to move it. If it works, don't fix it.