Turbo spools under thermal expansion. If you're just cruising at speed you'll see very minimal boost. Unloaded going down the main drag at 45 I typically see 2-4psi. You'll see most boost when accelerating or when loaded. You also want to make your turbo spool linear with your throttle input. If you just mash the go pedal, you'll get very slow spool and lots of smoke. Roll into the throttle. As rpms increase, slowly give it more.