My Magnex used to gurgle loads about 3.5k revs IIRC. If not it was 2.5k, but it used to gurgle loads, no pops and bangs though. SuperSprint system with 3" Piper backbox used to pop loads about 4k revs and on the engine run-off but when changing to PH3s and map it didn't pop or bang at all, even after getting bodies mapped onto it. Saying that it might be doing it but might not hear it over the bodies
