Over the years I've built up some calculation spreadsheets to predict engine power and torque from air consumption, boost and efficiency (BSFC). I've had other spreadsheets to predict engine airflow from boost, volumetric efficiency and intercooling.
I had a burst of productivity last night and combined the two. I then set all the variables as close as I could to my 4BD1T using information from 4BD1T factory performance charts, observed boost and fuel pump settings.
These variables have all been set as close as I could estimate to my 4BD1T, it will also apply within reason to 4BD2T and 4BT engines.
Here are the basic variables:
RPM range from 800-3,600rpm in 100rpm steps.
VE starting at 0.9 at idle to 2000rpm, dropping to 0.8 at 3000rpm and 0.74 at 3,600rpm.
BSFC starting at 240g/kwh at idle, minimum of 215g/kwh at 2100-2200rpm and climbing to 257g/kwh at 3,600rpm.
Observed boost hitting 10psi at 1200rpm, 22psi at 2000rpm, 24psi at 2200rpm and dropping from there.
No intercooler, 20C intake temps, sea-level and 60% compressor efficiency.
A/F ratio used was 17:1.
Here are the results:
These aren't perfect, they don't include parasitics such as turbine drive pressure which are dropping more power at higher rpm than shown on the graphs. But they are a good indication. I think it's within 10% of reality at all points.