cause the one i got now is a BPV bypass valve, it actually lets air bypass the turbo into the inlet and also acts as a bov with recurclitation pretty cool huh, probley put it on the side where ur hks one is near the throttle body so it can suck air in easier so off boost no need for the air to traval through turbo, than intercooler. it just travels from after afm through a litte 1inch pipe to ur throttle body. than when on boost it shuts and works as a bov and if boost is higher hks one helps