you must be referring to a four cylinder, I hope. The other engines are simply crazy or exotic with turbo.
a four cyl does benefit.. subaru has been doing this forever. the 1980s versions are the act of math you are looking for, some even had carburators and turbos, all tuned by thier own extremely tight emission standards.
the timing of injection does play a factor in your quest..a downdraft carb cammed engine can make use of a smaller turbo, the injection will stay a slob with the same boost. in fact, that drove alot of hillbilles with thier subarus crazy...the carb cars with no turbo got twice the fuel mileage and passed them on the highway...
also, if you are over 9 to 1 compression, there willbe trouble, even for gentle turbo.
you may opt for a small charge another way to conquer the zero.
I still seek 3psi, coincidentally, for the similar reasons you are pursuing.
