Ok... this is what puzzles me:
if u use wideband o2 sensor for tuning... what do you plug to yr ECU? Especially if you use V/S-AFC? If tuning without o2 sensor.. wont returning o2 sensor screw up things a bit - of what you'we tuned to?

 

ok.. first.. AFC uses the MAP sensor not the o2.

and the ECU ignores the o2 at WOT and goes rich.

 

What crx88Si is saying is..

When dyno tuning, (tuning with a wideband O2, you tune open looped operation of your ECU. Which is strictly tables.

Then, these tables are referenced during closed loop (reading of the O2 by the ECU to get lambda) and a fuel pulse is generated based on an interpolation routine and O2 readings.

 

Ic.. that makes sense.
Tnx for info