I have made myself a leak test device out of pvc pipe in order to leak check my turbo and intercooler plumbing. I have removed the mass air sensor and the Y pipe. I have plugged the two hoses that ran to the Y pipe from the intercoolers and am putting the pressure in at the large boot that the mass air sensor was plumbed into. My question is why am I getting a large amount of pressure blowing out of the plenum where the Y pipe was removed? There should be know relationship with the intake plenum and turbos with Y pipe removed? This is a large amount of air blowing out the plenum and I can not build up any pressure while testing. The only thing I can think of is a vacuum line tied into the turbos is venting back to the intake. I am going to investigate some more but any input meanwhile would be greatly apreciated.