Last modified on 16 June 2010, at 23:13

NG 900/9-3 TB Manual Boost Control


The manual boost controller (MBC) is a simple device that can noticeably change the performance of your Saab. The ECU controlled solenoid valve will no longer limit boost in first and second gear, and wheel spin will be much more important to control.

The MBC does not work on the 9-3. On the 9-3 you must use a series install of a manual boost controller (SMBC). The SMBC will not increase the power available, it only removes the limiter from first and second gears.

This device installs between the turbo and wastegate. Max boost is now controlled by a the ball and spring valve of the MBC. The MBC can be tightened to increase max boost, but if the MAP sensor reads an intake pressure of more than ~15.5 psi it will shut off fuel to the engine. After the MBC is installed it takes about a half hour of driving and turning the MBC to achieve max boost without hitting fuel cut off.

Manual Boost Controller

Cost and Difficulty

  • Cost: $43
  • Time: 10 min Installation, 30 min Tuning
  • Difficulty: Easy


  • In the picture the "blue" hose goes from the turbo compression housing to the end of the Boost (APC) Solenoid and is marked "C".
    • Disconnect the hose from the Solenoid and connect it to the straight end of the MBC.
  • The "yellow" hose is left alone; it goes from the intake before the turbo to the Boost Solenoid and is labeled "R" on the Boost Solenoid.
  • The "green" hose is labeled "W" on the solenoid and is attached to the middle barb and wastegate.
    • Disconnect it from the wastegate and plug it back into the Boost Solenoids on the empty plug where the where the "blue" ("C") hose used to connect.
  • The 90-degree elbow of the MBC is plugged into the wastegate.

The instructions sound more complicated than the actual installation is.

APC - Boost Solenoid