First off I know any surge is bad, but I am running out of options here, I originally had the Forge BPV on my OEM tmic, after switching to the FMS FMIC I noticed a issue with in between shifts that made the car feel like it hit a wall before getting back on its feet. I have tried all the different springs with the valve, car still drives like crap, took it to a shop they could not figure out why as the forge BPV and FMS FMIC were a common setup. I picked up forge's full atmospheric valve to see how my car would drive, its a dual piston setup that cures any idle issues or stalls after lift off, my car drives perfect now, I can shift quickly without any bucking or hesitation; however at part throttle i can hear the compressor chirp from the intake side prior to the valve going psssshhhhh, I dont think its surging at WOT but I cant hear it due to my EWG, I have the softest spring in the BOV (yellow spring), I can try to get a special order spring from forge that is even softer but that spring not rated for higher boost levels.
Green - 5-15 PSI
Yellow - 15-23 PSI
Blue - 23-30 PSI
Red - 30 + PSI
Most people run the yellow plus 2 shims or the blue on the oem tmic, I only have the yellow in it right now and it still opens a bit late causing surge, please do not suggest WG flutter because it is not, I have an external wastegate that dumps to atmosphere.