What is a Sequential BOV?
A sequential BOV, or Blow Off Valve, is designed to be leak free for intake systems with higher levels of boost. Typical blow off valves are designed so that the presence of a vacuum on the intake side of the valve causes it to open, venting pressure to either the atmosphere or the intake before the compressor stage. With a sequential type blow off valve, the increased pressure of higher levels of boost tend to eliminate leakage by pushing the valve closed, because this type of valve opens with a pulling motion instead of pushing. The decreased pressure and increased vacuum of idle also help to keep the BOV from leaking at idle.