wastegate pressure + or -

[Chris and Alana]

I was just wondering if the stock wastegate actuator opens under pressure or vacuum? I suddenly started overboosting and found that the rubber tube going to my ebc solenoid had rubbed through (it was lying next to a pully) so my wastegate will not be opening at all. I have a T piece I can use to temp repair it and bung the T leg off (ineffect making a straight connection) but I was just curious as to whether there will be pressure or vacuum in there.