Air & turbo

Throttle body

Uses a movable plate to regulate an intake passage.

Throttle body
Rover K-series throttle body with position sensor and mechanical linkage. · No machine-readable author provided. M100~commonswiki assumed (based on copyright claims).
Look for: The circular passage, throttle plate and external linkage.
Where it sits

In the air path before the intake manifold.

How it works

An actuator turns the plate according to controller commands; its role differs with valve-lift control.

Think of it as

A controllable door in an air tunnel.

Symptoms when it fails

A sticking plate, air leak or electrical fault can cause poor response or an engine warning.

Lifespan

Filters follow the vehicle service schedule; ducts and boost hardware are inspected for condition, sealing and operation.

Repair cost

A hose or filter is generally simpler to service than a turbo assembly. Access and diagnosis can dominate cost.

The BMW angle

BMW engines with Valvetronic can still have a throttle body for specific operating functions.

Used in

BMW combustion models; boost hardware applies to turbocharged engines only.

Sources
Same system

Air & turbo

Engine air filterRemoves dust from air before it enters the engine.Air-filter housingHolds the air filter and directs clean air into the intake.Intake manifoldDistributes incoming air to the cylinders.TurbochargerUses exhaust energy to push more air into the engine.Turbo wastegateDiverts exhaust around the turbine to help control boost.Turbo diverter valveRelieves compressed intake air when operating conditions call for it.Charge-air coolerRemoves heat from compressed intake air.Charge pipeCarries pressurized air from the turbo toward the engine.