More fuel questions...mainly cruising and part throttle
 

Ive noticed when people do runs to check for air/fuel with the vag its always full throttle.

If a rich condition occurs how does that affect the part throttle and normal driving? Will a rich condition still occur or will the computer correct for this somehow?

I guess an example is pc16 with 3bar fpr. Everyone knows this will run rich but is that only full throttle or all the time?

Reason I ask is I am using a boost controller but it only activates at full throttle and uses the N75 the rest of the time. I would like to up the boost and fuel a little but dont know how that will affect "normal" driving. Would I still run rich at say highway crusing and part throttle or will the computer be able to correct for this?

during normal driving your car is in closed loop and depends on the O2 sensor readings
 

to self-adjust the a/f mixture to 14.7:1. Any changes to the a/f map, fuel pressure, air temp, etc. will be compensated for by the LTFT (long term fuel trim). The LTFT levels adjust the injector timing and there is +-20% compensation before a CEL is thrown.

Once you apply more throttle the ECU will switch to open loop (based on the load calculation, not necessarily WOT) during which it bases the a/f mixture purely of the build-in maps and trim levels. The O2 sensor readings are ignored. Any change to the a/f map at that point will result in direct change of the a/f mixture.

As a result open throttle is the only area that can be tuned, close loop can only be adjusted so that the LTFTs stay close to 0.

Thanks