Discussions on this forum have already estblished that the stock igintion system retards timing 1 deg per PSI of boost pressure upto 8PSI, from this point on it is static due to the FCD and Boost pressure sensor. ( search is you wana find out about this )

What i want to know is about about how timing is altered to compensate for increased air mass/density
by this i mean, the stock ignition system can handle running 11-12psi boost with the appropriate fuel upgrades on the stock turbo.

If you upgrade the turbo and thus subseqently increase the air flow/mass/ density would the stock timing system still be ok if running the same boost pressure. as long as you had the fuel to match?

People who have tuned with aftermarket EMS would know this ( i am not one of them )

How does the timing maps change due to air flow mass?

Can i upgrade the turbo, keep the stock ecu for timing duties , run larger injecotors and a piggy back system or a fuel only computer such as the microtech MT4 to controll the fuel amounts