Ok, buildup is as follows...274" production headed offcenter, front mount, JC-45 .82 housing (i know it's small), 83's, FAST, stainless headers, etc....Just put the FAST on it and decided to take it out to tune on it a little on the interstate. With copilot I did a 0psi pull, 5psi pull, and a 10psi pull just to see where the A/F was at. While holding it steady at about 7psi the compressor wheel starts to surge. Anyone have any experience with this? New one on me...Wide open it's fine, just needs more turb on it. Could this turbo be flowing more air than the engine needs at 10psi? Or vice-versa, engine flowing more air at 10psi than the turbo can provide at same psi? Blow off valve needed? Thx Scott