hello all first post here. i have a semi built ls/v 9.5 : 1 comp with mahle powerpak pistons stock bore , eagle rods, gsr head w/type r cams and all the other goods stuff. my problem is when is start to make positive pressure 5psi 4500 rpm i hear the turbo sound like its poping popcorn (not a back fire) and the car feels like its holding back. when i let go of the gas pedal and the bov goes off the car drives fine until i hit 5psi . when i do drive the car normal under no real load she is ok.
i have a 3" dp and 3" exhaust tubing to a magnaflow muffler. i am using uberdata and have add fuel and taken fuel to the boost columns and still the same. the WB reads 12. 1 when im at 5psi i know thats rich. i hope u guys can help. i have been also trying to data log and have no sucess. using uber 1.7 ost

 

where is your timing?


that sounds like detonation to me

 

Def sounds like detonation. I describe it as a marbles on your valve cover type sound.