My feeling is that the ALDA cannot make up for a turbo that will only produce 6psi. The turbo spins based upon volume. If the engine is running very lean, then the volume will be down, and the turbo will not develop full boost at lower rpm's. However, once you get it above 3000 rpm's, there is now enough volume to spin the turbo up to the required speed to get full boost (12 psi).

There is a way to rig this test to determine the answer, one way or the other. If you have a portable air tank and a regulator, disconnect the ALDA from the protection valve and connect it up to the portable tank and regulator. You will need a valve in the line.

Take it out for a test and apply 12 psi to the ALDA when the engine is under full load above 2300 rpm. Monitor the boost gauge and see if the manifold pressure comes up above 6 psi. If it remains at or about 6 psi, you have confirmed that the turbo is not reaching design speed, or, has damaged impeller blades.

This test will avoid the need to mess with the ALDA adjusting screw and the inherent risks associated with that.

I'd be very curious as to the result.

I'd also be very curious as to the result of adding 12 psi to the ALDA with the power backed off, such as cruising at a steady 60 mph. I always wanted to try this to see how much smoke could be produced. This is my dream of a proper "proximity regulator", and, if successful, I just might add it to the SDL if I can cobble up the proper switching valves. Of course, I'd need to add an onboard compressor of some fashion.