Okay, I'm home sick as a dog with the SO and have just typed up for someone how to tune Boost Comp via a PM. Since everyone keeps asking about this I'm going to also post what I've typed here to help others understand. Here goes:
Well, you need to get the car running and driving first before you can do this.
Lemme' briefly explain the concept behind Boost Compensation tuning - If at say 4K RPM and 100KPA you need X amount of fuel to get Y A/F then at 4K RPM and 200KPA you will need 2X fuel to get the same Y A/F. Make sense? Yes, in extreme cases the VE of the motor will change at some point due to restrictions somewhere but for the most part this concept holds true.
If you look at a Full Boost Comp'd mapping you will see that all fuel columns are the same vertically. The way that fuel is taken care of is there's a Fuel Modifier table called Boost Fuel Correction. This is setup usually so that say 100KPA is a "zero point" - no change (the zero point can be anywhere you choose). But 200KPA effects a +100% change in fuel and 0KPA is a -100% change in fueling. Points in between are linear. Making sense so far?
Now - you can Boost Comp a mapping that's done cell by cell just by applying those % changes to the existing map. The effect is greater granularity in fueling although you MAY need to modify something called the MicrosecBit. MicroSecBit defines the number "1" in the RAW view of the fuel map - more on that later
Okay, so you now have a mapping that is Boost Comp'd but numbers up and down are not the same - should drive as fine as the original map. You can stop at this point or go further. IF you stop here, as I did once upon a time, and tune multiple load rows for the same A/F you'll get a surprise as they all become the same number
Okay, go do a WOT pull at the lowest load value your W/G will allow - easy if it's a N/A motor! Tune that load row to whatever A/F you need WOT and make the cells above and below that load the same so there's no interpolation. If you take those numbers you get and apply them anywhere you go WOT you should find that you maintain the same A/F in those load areas that you tuned for. You now have what I call a "Hybrid" Boost Comp map because the vac areas are cell by cell.
You can leave that if you want.
To get the vac area done for a "full" Boost Comp map continue copying those same numbers down vertically - the car will now run pig rich. Go into a table called the Throttle Inj Modifier. Adjust the table so that at idle you have a decent A/F and then go for a drive. At cruising speed\throttle adjust the table so that you get a decent cruise A/F and then calculate between the two points to get a linear table. Play with this some but in the end you'll have a table that removes more fuel as the throttle is closed (mine is -26%) and less at say 50% throttle (mine is -3%) in a linear table. Ta Da - "full" Boost Comp.
Another way to do those vac areas is to do a little math. Say you want 12:1 in one row but the vertical numbers give you 11.5:1 - calculate the percentage of difference between the two and either apply that to the Boost Fuel Correction table for that load range or to the fuel table load area. Do this for every area you want something other than whatever your WOT fueling was. In this case there's NO Throttle Mod table filled in. So, why do it this way? Because some small turbos will spool at part throttle - say on hills and things. With Full Boost Comp it's also possible to get into a situation where say the car is lugging on a hill and more throttle just makes it go pig rich but load doesn't go up quickly. I'm actually about to convert to this method to try it out.
Make sense? Lot's of ways to skin this cat!