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Turbocharger Terms and Definitions

Turbocharger Terms and Definitions:

The turbocharger terms and definitions used to describe turbocharger operation can be confusing.

Turbocharger Terms and Definitions:The turbocharger terms and definitions used to describe turbocharger operation can be confusing.
Turbocharger Terms and Definitions: The turbocharger terms and definitions used to describe turbocharger operation can be confusing.

Here are some definitions for common turbocharging terms:

■ Boost Threshold

Boost threshold is the optimum engine speed to produce exhaust gas flow to create positive manifold pressure (boost).

■ Turbo Lag

Turbo lag is the time delay between the point when the throttle is opened and the turbocharger boost reaches operational speed when the engine is running at boost threshold.

Many factors affect turbo lag:

Engine tuning status; the condition of the rotating components; operational condition of the control sensors and components; the presence of any air leaks in the turbocharger system; the control settings; and even the weather.

■ Boost Leak

When air (boost) is leaking within the turbo system or intake, it is referred to as “boost leak.” This may be caused by loose assembly of the components, a bad seal or a cracked component. Under such a condition, the turbocharger may not create enough boost pressure, or reach adequate levels.

■ Boost Spike

A boost spike is an erratic increase in boost pressure, mainly experienced when the vehicle is accelerating through the lower gears and the controller can’t adjust to the changes in engine speeds as quickly as would be ideal.

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Subaru Turbocharger Explained Part 2

Subaru Turbocharger Explained Part 2:

Service Procedures

Here are some service procedures, including steps to properly remove turbocharger components, and tests and inspections you can perform to check component operation.

Subaru Turbocharger Explained: Here are some service procedures, including steps to properly remove turbocharger components, and tests and inspections you can perform to check component operation.
Subaru Turbocharger Explained: Here are some service procedures, including steps to properly remove turbocharger components, and tests and inspections you can perform to check component operation.

Intercooler Removal

You may need to remove the intercooler to work on other components beneath it. Removal of the intercooler must be performed carefully so that no damage occurs.

1.) Disconnect battery. Remove the two bolts that attach the bypass valve, then the valve.

2.) Remove the bolts from each end of the intercooler and disconnect the crankcase ventilation hoses from the intercooler.

3.) Loosen the clamps at the throttle body and outlet of the turbocharger.

4.) Gently move the intercooler side to side until the tension of the hoses at the turbocharger and throttle body loosen.

5.) Remove the intercooler from the engine compartment and cover the open areas with tape to prevent foreign material from entering, which could cause damage to the engine or turbocharger after re-installation.

Turbocharger Removal

1.) After removing the intercooler, remove the intercooler mounting bracket.

2.) Remove the eight bolts that secure the protective heat shield around the turbo.

3.) Raise the vehicle and disconnect the rear oxygen sensor harness, then remove the front exhaust pipe mounting bolt. Position the pipe so there is some movement.

4.) Lower the vehicle and disconnect the wastegate hose to the vacuum hose leading to the wastegate control solenoid.

5.) Remove the coolant hose from the reservoir that connects to the turbocharger.

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