Multiair Recirculating/Blow off valve.
One of the most common problems of multiair engines is the operation of the Bov's.
-Multiair's have the ability to control the amount of incoming mixture directly throug intake valves. Thus, they dont normally use the throttle body except of emergency or stand by situations. As a result when we lift the throttle after boosting throttle body doesn't close and the vacuum inside the intake manfold that is created, is incostant and insufficient to operate the bov's piston. So, bov fuctions in random cases under random circumstances. After a while Ecu diangoses the fault without a ckeck engine light. This, can cause either partial closing of the throttle , or way too sensitive throttle which cause partial opening of the bov and boost leak.
-The solution: Stock recirculating valve is mounted on the compressor wheel housing and operates only via ecu's signal. When upgrating the turbo, we can mount the stock valve in an appropriate adapter which convert it to blow off valve. Thus, our valve operates only when it has to and our ecu is always pleased