Turbo Upgrade: More Boost for Your Engine

Hello friends,
Okay, some people might think I'm not thinking clearly, but I have a 1Z engine with a chip, producing about 120 horsepower and around 300 Nm of torque. I've been considering how to get a bit more power out of it. Currently, my boost pressure is around 1.1 bar, and I was thinking of increasing it to 1.15 or 1.2 bar. Of course, I would also need to adjust the fuel accordingly, but only enough to avoid excessive smoke. Right now, the smoke output is quite good, so not much at all. The engine has about 150,000 km (approximately 93,000 miles), and the transmission has around 250,000 km (approximately 155,000 miles).

Because I read somewhere that a 1Z engine, without any other modifications, can potentially produce around 130-140 horsepower, but I don't want that much; I was thinking more along the lines of a maximum of 130 horsepower.

What do you think about that?