Audi TT Turbocharging and Forced Induction Systems

Question 1

What type of turbocharger is used on the Audi TT 2.0 TFSI engine?

Accepted Answer

Twin-scroll turbocharger

Answer

The 2.0 TFSI uses a twin-scroll turbocharger that separates exhaust pulses from cylinder pairs to improve spool response and reduce turbo lag.

Question 2

What is the typical boost pressure range for a stock Audi TT 2.0 TFSI (Mk2)?

Accepted Answer

10–15 psi (0.69–1.03 bar)

Answer

The stock Mk2 TT 2.0 TFSI operates at approximately 10–15 psi of boost under normal driving conditions.

Question 3

Which component is responsible for regulating boost pressure by venting excess exhaust energy on the Audi TT turbo system?

Accepted Answer

Wastegate

Answer

The wastegate diverts exhaust gases away from the turbine wheel to limit and regulate maximum boost pressure.

Question 4

What is the purpose of the diverter valve (DV) found on the Audi TT's turbo system?

Accepted Answer

It recirculates compressed air back to the turbo inlet when the throttle closes

Answer

The diverter valve (also called a recirculating bypass valve) vents pressurized intake air back upstream when the throttle closes, preventing compressor surge.

Question 5

On the Audi TT, the N249 valve is associated with which function?

Accepted Answer

Turbo boost pressure recirculation bypass

Answer

The N249 is a solenoid valve that controls the diverter valve, helping manage boost pressure recirculation to prevent surge.

Audi TT - Certified Audi TT Specialist Practice Test

Audi TT - Certified Audi TT Specialist Practice Test

Audi TT Turbocharging and Forced Induction Systems