[WRX_XB9R]

Questions for the more technicaly involved with the ECU than me.

Which O2 sensor does the ECU use for tuning?
If we are able to change this sensor to a wideband unit will it read properly for the ECU?
Are the limits that I see on my logs caused by the ECU or the sensor itself?
Can we then have more acurate AFR maps vs. O2 reading instead of the offset that we have currently?

Any other ideas on how to make the factory ECU work better for our performance tuning? I really like the factory ECU ability to control anything I just want it to work even better.

[WolfPlayer]

The ECU uses the front O2 for AFR changes.

No. A wideband O2 must be properly mated to the correct hardware that will power/heat/control the wideband O2. The scooby ECU isn't setup for this (free air calib, heater calib, etc).

The limits (in terms of AFR), AFAIK, are ECU limits ... with regard to what you are seeing in your datalogs (11.x low and 20.5 high).

It will never be more accurate unless a wideband is in place ... hence the reason for your questions.

IMHO, it would take rewriting of some of the ECU code to run a wideband in place of the stock O2. I was pretty heavily involved in the domestic ECU world when I had my camaro. It used the VERY popular 730 ECU (around since 1989). People hadn't even worked that type of code into that platform yet (and the code is well known and available for anyone to write the hacks). The only ECU that I know of where people actually rewrote the code to work with a wideband is the old Turbo Buick ECM.

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