Car Tuning Forced Induction Systems Questions and Answers

Question 1

What is the fundamental difference in how a turbocharger and a positive-displacement supercharger derive their power?

Accepted Answer

A turbocharger is driven by exhaust gases, while a supercharger is driven by a belt from the crankshaft.

Answer

A turbocharger is driven by a belt from the crankshaft, while a supercharger is driven by exhaust gases.

Answer

A turbocharger uses an electric motor, while a supercharger uses intake manifold pressure.

Answer

A turbocharger uses intake manifold pressure, while a supercharger is driven by an electric motor.

Question 2

A tuner is pressure testing a newly installed turbo system. They notice that as boost pressure rises with RPM, it eventually exceeds the target set by the wastegate spring and continues to climb. What is the MOST likely function of the component that is failing or improperly configured?

Accepted Answer

To control the turbocharger's speed by diverting exhaust gas away from the turbine wheel.

Answer

To cool the compressed air before it enters the engine.

Answer

To lubricate the turbocharger's rotating assembly.

Answer

To release excess pressure from the intake piping when the throttle closes.

Question 3

A customer's recently modified car with a large turbocharger makes a distinct 'chuffing' or fluttering sound under high-load, low-RPM conditions. The boost gauge needle flickers wildly during these events. Which of the following is the MOST likely cause?

Accepted Answer

Compressor surge.

Answer

A boost leak after the throttle body.

Answer

Normal blow-off valve operation.

Answer

Excessive turbo lag.

Question 4

Which of the following is the PRIMARY purpose of installing an intercooler on a vehicle with a forced induction system?

Accepted Answer

To cool the compressed intake air, increasing its density and reducing detonation risk.

Answer

To increase the temperature of the intake air for better fuel atomization.

Answer

To act as a secondary air filter for the intake charge.

Answer

To muffle the sound produced by the turbocharger or supercharger.

Question 5

A customer with a turbocharged engine that uses a Mass Airflow (MAF) sensor wants to install a valve to vent boost pressure when the throttle closes. To ensure proper engine operation and avoid a rich air-fuel condition, which valve is the correct choice?

Accepted Answer

A diverter (bypass) valve that recirculates air back into the intake tract before the turbocharger.

Answer

A blow-off valve (BOV) that vents the pressurized air to the atmosphere.

Answer

An external wastegate plumbed into the downpipe.

Answer

A manual boost controller installed on the compressor housing.

Question 6

Which type of supercharger is characterized by its positive-displacement design, providing instantaneous boost at low engine RPM, but is often less thermally efficient at higher boost levels compared to other designs?

Accepted Answer

Roots-type supercharger

Answer

Centrifugal supercharger

Answer

Exhaust-driven supercharger

Answer

Variable-geometry supercharger