Cold intake air is preferred over hot air because it is ________.

• A. It is denser, providing more oxygen per unit volume.
• B. It is warmer, which improves combustion.
• C. It has more moisture.
• D. It reduces engine weight.

Answer: (A)

The main idea here is that the amount of oxygen available for combustion depends on how dense the intake air is. Colder air is denser, so it contains more oxygen molecules per unit volume. When more oxygen is present in the cylinder, more fuel can burn, which increases power and improves combustion efficiency. Warmer air, being less dense, provides less oxygen per volume, which can limit performance. Moisture content in the air isn’t the primary factor that boosts performance, and intake air temperature doesn’t affect engine weight.