That's for a stock 4BD1T. Here is the upgrade list for increasing the 4BD1T's torque.
Stage 1.
Turn the fuel screw to hit 750C in worst case.
Cost. Nothing.
Torque around 380Nm.
Stage 2.
Modify the wastegate actuator to increase boost to 20psi (cut, thread, install sleeve nut and locknuts).
Cost. Minor.
Torque around 420Nm.
Stage 3.
Fit intercooler with 20psi boost
Cost. From $400 in parts on up.
Torque around 510Nm.
Now these figures are all based around a very conservative clean and safe air/fuel ratio. If you want to run hotter you can and get significantly more torque.
I was getting over 500Nm with just 20psi boost and no intercooler. But it was a hot tune that required an eye be kept on the EGT gauge.
To go past the figures above you need to upgrade the turbo. There are various options around the $1000 mark and plenty both cheaper and dearer.
Your 4BD1T stats are factory figures off wikipedia. I wrote those.
There is a guy in the US who had compound turbochargers, a massive intercooler and a custom fuel pump on his then unopened 4BD1T. The stock head-gasket let go somewhere over 60psi boost. They are a very strong engine and will produce far more power and torque than your driveline can handle as long as you can feed them enough boost.
They are quite different engines. The 2.8 being the end of a long evolution of small engines, the 3.9 being a heavy duty truck engine made to last 500,000km between rebuilds.



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