First things first, check for boost leaks.
Fuel cut is determined by a number of different inputs, intake air, volume of air, coolant temp, throttle, rpm, etc.
FC is obviously protection against leaning out your motor. (catastrphic failure comes to mind. IE: wastegate actuator hose cut/melted.)
There are a few ways to get past FC, all the 'safe' forms involve scaling the airflow signal the ECU 'see's' (via airflow signal). I'll get back to this in a minute.
Why FCD is a No-NO! The FCD basically goes in between the AFM and the ECU and does not allow the airflow signal to go above XX amount of airflow. XX is right before fuel cut.. therefore fuel cut is not triggered. The problem with this is the ECU see's XX airflow, if there is additional airflow, the ECU is NOT dumping the fuel to compensate for it because it doesnt 'see' it. If you have boost creep this is especially bad. (see dyno graph of boost creep+FCD = lean!)
Lexus AFM + 550's. allows more boost because the AFM is 25ish% bigger, you pair it with 550's because they are 25% bigger as well. This allows the right balance of airflow and fuel (by theory at least). This is an example of scaling the airflow signal.
More FP/bigger injectors + piggyback. This is what I did with my MAF-T when was still hitting fuel cut. I upped the fuel pressure (richening the mixture for saftey) and I cut back on the airflow signal (pushing FC further away and compensates for the richness from upping the FP). This works great, as long as you arn't running too much fuel pressure, and if you HAVE A WIDEBAND. Its too dangerous to just guess with this setup.
A lot of times this doesnt make sense the first time you read it, and I'm not the best at explaining it. Give it time, think it through and it'll make sense
Edit: As shaeff mentioned.. PLEASE make sure your fuel pump is up to the task before messing with the FP!
