I got my T2 and am in the process of getting her preped for her new home. When i realized i have now split air pipe i can just block it off right? I know on the 6 port motors it opend up the 5&6 ports but i have no idea what it is used for on the turbos.

The split air pipe supplies o2 to the cat to further assist the burning process of unburnt fuel coming through the exhaust... blocking it off really doesnt gain you anything, i'd leave it alone until you modify the entire exhaust....

it does almost nothing in a turbo, under certain conditions its used. car passes fine without it