Car Tuning Engine Performance Principles Questions and Answers

Question 1

Advancing ignition timing typically results in which of the following outcomes?

Accepted Answer

Increased risk of engine knock at high loads

Answer

Decreased peak cylinder pressure

Answer

Improved engine torque at very low RPM

Answer

Reduced engine heat generation

Question 2

A tuner is aiming for maximum power on a turbocharged gasoline engine. Which air-fuel ratio (AFR) is most appropriate to target under full boost?

Accepted Answer

11.5:1

Answer

14.7:1

Answer

15.5:1

Answer

13.0:1

Question 3

What is the primary function of a camshaft in determining an engine's performance characteristics?

Accepted Answer

To control the timing, duration, and lift of the intake and exhaust valves.

Answer

To regulate the engine's operating temperature.

Answer

To control the timing of the ignition spark.

Answer

To determine the engine's redline.

Question 4

A customer complains of sluggish turbocharger response and a noticeable loss of power after installing a new, highly restrictive 'quiet' muffler. What is the most likely cause?

Accepted Answer

Excessive exhaust backpressure

Answer

Increased volumetric efficiency

Answer

Reduced ignition timing advance

Answer

A richer air-fuel ratio from the ECU

Question 5

Which of the following best defines Volumetric Efficiency (VE)?

Accepted Answer

The ratio of the actual amount of air entering the cylinder to the theoretical maximum amount it could hold.

Answer

The ratio of an engine's horsepower to its displacement.

Answer

The measure of how efficiently fuel is converted into power.

Answer

The speed at which exhaust gases exit the engine.

Question 6

During a high-load tuning session on a dynamometer, the knock sensor detects detonation. How will a modern Engine Control Unit (ECU) typically respond?

Accepted Answer

Retard the ignition timing

Answer

Increase fuel pressure

Answer

Advance the ignition timing

Answer

Open the EGR valve