Boost issue?

Hello. I am new here. I recently picked up a 1986 Turbo Z 2 seater. I found it in a barn in pretty rough shape, hadn't run in almost 10 years. Anyway, fast forward a few weeks, I have it running. It had a water to air intercooler on it, which I removed because it leaked water at the heat exchanger, and water into the intercooler. For now I am running without the intercooler until I set up a new one. I already custom installed a new heat exchanger and a water pump, now waiting to decide on what intercooler to get, since it looks like the original was custom built to barely fit in place between the turbo and throttle body. My situation now is this:The car has a manual boost controller mounted in the cockpit. No matter where I turn the knob, I get 8 pounds of boost on the gauge. All the way left, or all the way right. I thought, since this may be a 30 year old part, maybe it's gone bad? So, I just installed a new one, and started at factory initial setting- it showed 8 psi. Turn the knob a full turn, same. Keep doing this until knob is all the way seated, still 8 psi. Can anyone tell me what might be going on? I am perplexed. Thanks! And by the way, I once owned a 1988 Turbo Z, completely stock, and I can tell this one is faster. Just doesn't look as nice (yet).
Mark