Boost Pressure Test

911 Turbo
1. Disconnect boost pressure control switch electrical connector, then the switch. Switch is located behind pop-off valve housing.
2. Using necessary threaded adapters, connect suitable pressure gauge to boost pressure control switch port. Ensure pressure gauge hose is long enough to reach passenger seat.
3. With assistant in passenger seat, drive vehicle with engine operating at 4500 - 5500 RPM in first or second gear, using brake to limit RPM, and have assistant read off maximum boost. Boost pressure can only be checked during acceleration. Perform test as quickly as possible to avoid overheating brakes.
4. Maximum boost should be 10 - 12 psi.