Hey y'all, just fitted a RamAir foam cone filter to my T-Jet, i get the nice spool of the turbo and tssssh sound, however at low revs it groans and cruise at steady speed theres a sound which i can only describe as an "whoosing air loss" sound, like letting air out of a tyre, also pops when revved and let back to idle. this normal???

Thanks
Ste

anybody???