I am no expert in A-series turbocharging. However, looking at turbo kits for the Nissan L-series, I would say no more than 5psi for this motor, as it is "draw through" and not "blow through".

There are several problems with the draw through turbo systems, they include:

1. A situation called "flame back" where, under certain circumstances, the air/fuel mix in the turbo/induction system can ignite inside the them and literally shoot out of the front of the turbo. This can cause SERIOUS damage and toast the car. do not put the air filter too close to the turbo in this system; put it very far away.

2. During, particularly off-throttle moments, the air/fuel mix can settle out inside the turbo compressor housing.

3. No blow-off valve can be used in the draw-thru type since it would vent air and fuel into the atmosphere, VERY BAD! Since you would not have a blow-off valve, you would have a bad case of compressor surge during off throttle periods. This is bad for the turbo and its seals, etc.

4. No intercooler, very limited boost!

Just so you know!