4 Port Mac Boost Control Solenoid (FR-UNI-4PORT-BCSV)The Full Race 4 Port MAC Boost Control Solenoid Valve is designed to precisely manage boost pressure, delivering a clearly defined boost curve and improved response. Unlike a traditional 3 port solenoid, the 4 port design is highly effective in both low boost and high boost applications because it precisely directs pressure to both the open and close ports of your wastegate diaphragm. This functionality allows for a much lighter wastegate spring