Guys, one thing I have been doing for a while now with my personal calibrations is Throttle based V.E. (Alpha N) instead of map based. As you all know manifold pressure doesn't change V.E., however Throttle blade angle and back pressure does. Previously (verson 2 and earlier) we had Pressure ratio as our 'Y' axis input for V.E. the problem there was it was confusing to tune, and was still affected by Throttle angle. Now that I have broken that out into a separate trim table, we can effectively use Throttle angle as our 'Y' axis input. We are still TRUE Speed Density as manifold pressure is still being compensated for along with the density calculations. Previously back pressure would get in the way of doing things this way as there was no way to adjust the map when back pressure increased when running the turbocharger higher. Now that this is all separate, Throttle V.E. does several things for us.

1 - By mapping against throttle angle, we minimize the amount of accel fuel needed.
2 - The V.E. table is much more accurate at each site because we are now accurately compensating for actual v.e. changes
3 - Throttle response is increased due to added accuracy at each point.

To do this properly, you MUST have a backpressure sensor setup to give feedback for high boost trims to fueling against backpressure changes.

If you REALLY want to achieve optimal drivability, you change your load input as well so timing is load based (APC) instead of map. This is how the factories do this. Benefits are as follows

1 - Optimal timing at all manifold pressures. Currently with map based timing, you can't have optimal timing at 100kpa (zero vacuum/boost) because the engines load conditions can vary greatly at that point with no manifold pressure changes.
2 - Due to the optimal timing, fuel economy is increased
3 - Drivability is significantly improved because of the increased timing during transients

Draw backs to this method is mainly that you will need to determine your calculated load to set up your timing map. I.E. you won't know where 5krpm and 20psi occurs (as an example). The good news is you can setup your load information and log it while you are still in map based timing to determine where you need to be.