O2 Placement in exhaust

[Noddle]

Hi,

I'm about to fit my O2 sensor, and I'm not sure how far the end of the sensor should be in the exhaust, should just the tip (with the holes) or the base with the tip be in the exhaust, see picture if i'm not explaining myself.

 

NIgel

[Tony D]

You want it as hot as it can get, as quickly as it can get.

The standard bungs you can buy usually have a mix between "A" and "B" in your drawing. If it's a heated sensor, and it's placed reasonably close to the heat source (post turbine for that application) then you can get away with "B", and can monitor how much your heater comes on at idle and low speed to determine how well the exhaust stream is heating the sensor. The further away from the engine you put it, the more it has to be set up like "A" just to get it hot enough to run without the heater circuit on all the time.

Technically many of the WBO2 sensors heat themselves and that's all you need, but for the NBO2's you want it close so you can keep it out of the exhaust stream, with just the sensor tip inthe flow, and not the whole body.