Oxygen sensor placement?

[88SuperETABD]

So I know the o2 sensor needs to be added before the cat, and between 10 and 2 oclock up top, but here's my question and I searched but failed to find an answer,

So for these headers, for my m20


They come with a bung, but there is 2 collectors, and one o2 sensor...is it best to have an x pipe and drill the bung into that x so it reads from all 6 cyllinders(How BMW did it) rather than 3. I contacted topspeed and waiting for them to get back to me with the answer, if its okay to just do it in one collector, which do i put it in? Front or back 3 cylinders? Does it matter?

I'll be piecing together my exhaust, got Scorpion Oval catback coming in the mai,re using my high flow magnaflow cat (lessthan 5k miles), and these headers.

[Grant318is]

IMO, I would stick with the factory design.

[jlevie]

On an M20, the O2 sensor must be where it sees the flow from all six cylinders, just like where it is in the OE down tubes.

[88SuperETABD]

I'm thinking I should cut off the stock one and re-use it.


Is it supposed to be as close to the headers as possible?

[tonerrrr]

I'm thinking I should cut off the stock one and re-use it.


Is it supposed to be as close to the headers as possible?

I'm not sure about your setup but here is where mine is for my 86e:

[88SuperETABD]

thats not the stock location is it? Seams far back, mine originally was able to be taken off from under the hood. I didnt have to crawl underneath.

[george graves]

On an M20, the O2 sensor must be where it sees the flow from all six cylinders, just like where it is in the OE down tubes.

I don't think this is true. Ideally yes, you'd have a small crossover pipe. But I've been running my m30 on one bank of cylinders for years and it runs great. How do I know? Cause I have a wideband on the other downpipe.

Is it supposed to be as close to the headers as possible?

Too far away and it won't get the heat it needs IIRC.