Higher Gears for Turbo Cars

Just to drive the point home, running the wastegate off the spring alone will cause the wastegate to open prior to reaching the rated spring pressure. IE, your 13lb wastegate spring is probably starting to crack the wastegate valve much earlier than that, probably around 7psi. Running a MAC valve boost controller allows you to essentially pin the wastegate valve shut until you reach your requested boost pressure. It does this by pushing up under the wastegate valve diaphragm, either with compressor discharge air or CO2 from a bottle, keeping the valve closed.