Boosted Impreza RS with stock ECU running lean

Hi

Im tuning 2005 Subaru Impreza RS 2.5 (EJ253 stock internals) which has custom turbo kit. It has rotated td04, fmic, pink oem STI injectors (550cc/min), upgraded fuel pump. Fuel pressure regulator is stock.

Im tuning stock ECU with Ecuflash and use Romraider for logging.

Problem I have is that it runs super lean if applied throttle aggressively. I have used 2004 STI injector settings (size,latency,tip-in etc.). I would assume that Im pretty close with stock settings, but that's not the case. I have tried to increase tip-in without success. Can't figure out if it's tune or hardware related. What looks weird is increase of MAF volts when applying additional throttle.

Only had access to stock "wideband" sensor and relaying on that information.

3rd gear log and tune attached. Thank you for your help!

I don't tune those on stock ECU with forced induction so I apologize I cannot offer firsthand experience with what you're doing. Nevertheless I'll try to help you work through it.

Have you verified the range of the factory MAP sensor is sufficient, and confirmed the ECU doesn't have any hard coded limits since it was not designed for boost?

Have you confirmed you aren't exceeding the maximum load or maximum airflow values? These are present in other Subaru ECUs of that era, so perhaps in that one as well.

Does this occur if you apply throttle more gradually and achieve similar MAF V, MAP, calculated load values without the sudden throttle transition?

Been a while since i used RomRaider on a Subie. But i believe there are extra tables used by the WRX and STi's that aren't enabled in the RS ECU by default and some of the tables have different ranges in the axis to account for the extra load areas. This site i found handy as i could compare base maps and settings

https://www.romraider.com/forum/viewtopic.php?f=35&t=7591