update..
done the following to the car
HKS panel type air filter
Cat back exhaust (custom dual setup with Fujitsubo muffler)
Stillen oil cooler
Uprev flash (the logging was done using stock map)
Notice the bank 1 is always richer by about 0.5 than bank 2, and base fuel schedule is lower by 0.5 also. the AFM voltage is also dropped, which most probably means I lost power rather than making power.
Not sure if flashing to Uprev causes this issues (although running stock map) or it has got to do with the mods above.
I will try flashing back to stock ecu (before uprev) with the same mods and see how it compares.
The run was also done in the 3rd gear this time rather than in the 2nd gear in the first post, I will have to do another 2nd gear run also to make it more comparable. I shouldve done it using 3rd+ from the first place I was being lazy and did not want to drive far from home
I am wondering if it has got anything to do with the oil cooler warming up the air on one side, although I would guess that the gush of air from driving at 150kph would make that difference negligible.
so what I gotta do is
1. Remove Uprev temporarily
2. Measure the same parameters in 2nd and 3rd gear
3. Compare the 2nd gear run vs first pic
4. Compare the 3rd gear run vs second pic