As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT WiTH FULL THROTTLE AND THE WASTEGATE CLOSED, ENGINE HAD EXCESSIVELY LOW BOOST. (TURBO CHARGER INSTALLATION WAS AN AFTERMARKET INSTALLATION. ALSO, RECORDS WERE UNAVAILABLE AS OF THIS DATE TO DETERMINE AIRCRAFT TIMES, TURBO CHARGER STC, ETC).