Egg harbor 52 convertible with twin J&T 692 DDEC engines, 625 HP. Problem with starboard engine running fine up to 1825 rpm's, and then engine makes a slamming noise coming from just before turbo. The boost pressure runs 22 on this engine and the other running smooth at 11. Can not come up with any mechanic that has run into this problem? Motor runs out well below this rpm, temp, oil pressure and such register fine. Had injectors checked with electronic tool, and test within tolerances. Need suggestions and help?