Does o2 sensor position matter?

[Dxs]

Hi all,

I am manual converting a RA3 Odyssey with a F23a. The only manual ECU available is from a CG5 Accord with a F23a.

On the RA3 the o2 sensor is very close to the cat. On the CG5 the o2 sensor is alot closer to the head where two cylinders merge.


I am wondering if it is ok to leave the o2 in its current position near the cat, or if i should move it to match the ECU, being near the head.
See pic.

Obviously it would be easier to leave it as is.

http://i58.tinypic.com/2u5cc5u.jpg

[ECU-MAN]

RA3 position should be before the flex, CG5 position should be at the point where 2 ports meet the 4. Do not mount the O2 on the 2 ports only.

In the picture the O2 should be mounted where the threaded hole is after the mounting bracket and before the flex.

[Dxs]

RA3 position should be before the flex, CG5 position should be at the point where 2 ports meet the 4. Do not mount the O2 on the 2 ports only.

In the picture the O2 should be mounted where the threaded hole is after the mounting bracket and before the flex.

I just used the picture of the stainless headers for explanation purposes. I do not have aftermarket headers.

The question is, is that I am using an ECU that comes off a car that has has 4-1 headers, with the o2 in the stock location at around 30cm from the head (where the 4 pipes meet).

Where as my car has 4-2-1 headers and it's o2 sensor is like 80cm from the head. Will there be an issue given that the o2 is further away?

[ECU-MAN]

Yes there will be an issue..

The sensor must be placed at a location where the ECU can monitor all 4 ports not just two.

[Dxs]

where it is on the RA3 is where all 4 ports meet, as its on the 1 of the 4-2-1.

The question is more around latency etc. Will the extra distance from the head mean the ecu is reading the mixture too late? if that makes sense.