My question is really about how active the secondary turbo is before it starts contributing to boost? My secondary makes a loud screaming/whistle type of noise at exactly 4.5k until redline which I suspect means the turbo is going bad, but wouldn't it also make this noise during pre-4.5k spool up if there is something physically wrong with the turbo?

If the the secondary is fully boosting before 4.5k, but venting to the atmosphere until some thing-a-ma-jig redirects the boost into the normal intake path, then I would guess that my noise is coming from one of the valves that is controlling where the boost goes...

Anyway, any info will be greatly appreciated.

 

Right before tranistion I'll see 2-3 psi on the secondary if its prespooling.