G'Day All

Someone might know whats doing with my troll, i have only owned it for about a month now and am loving it, however, she is making a whoosh sound "kinda like a blow off valve" between gear changes.

Ive never really noticed any other turbo TD42's do this so am wondering if i may have something wrong?

She runs a 3+" dump pipe to a 3" zorst which is cut off about half way under the truck "temp". sounds tough as with the whistle and the whoosh between gear changes so if its not broken no point fixing hahaha.

Other info bout the rig is it is meant to be a ARB Turbo kit and is running a front mount I/C. Has a massive hair dryer bolted to it but the last owner said it has a economy tune.

Anything i should be stressed about?