Im not gonna read through the 9 pages of stuff here, but just gonna delve into this thread.
First, look where the stock BPV is located. ITs on the charge pipe, from the turbo to the IC. This is not the optimal placement for an aftermarket BOV, regardless if your going to recirculate or not. You will want a BOV located no closer then 5 inches to the TB and no more then 12 inches from the TB. This gives the pressurized air enough pipe/ic to travel through, before its vented, and create less back pressure.
With the current location, the TB closes, and pushes about 6 feet of piping, with pressurized air back to the BPV, and you have the charge air from the turbo going foward, the BPV, and an aftermarket cannot release the pressure from both directions. Thus, the air from the turbo is forced back, and will create the turkey/compressure surge, that the BPV/BOV is in place to stop.
It is an engineering oversight on MAzda.......again. It works fine in sotck form, but adding an aftermarket intake or BOV, worsens the situation it seems.
MY suggestion, get hardpipes with the BOV on the TB piping or go with a full fmic, that does the same.
