Just guessing???... But I presume it creates a cyclone effect, thus increases intake air flow? Where this works great on the Boss motor, Is utilising the diameter difference between throttle body & plenum chamber. (ATM standard throttle body is 76mm & plenum is 80mm) This is true for both 260 & 290
By the way, I also have one of these on my Pursuit and the throttle response IS improved markedly! I dynoed today 253.9kws which ain't TOO bad, just for exhaust, cold air PLUS one of these intake adaptors? I can't give before figure, as 1st time I've run her up.