Which statement describes the effect of larger exhaust pipe diameter on intake airflow?

• A. It improves intake airflow.
• B. It worsens intake airflow.
• C. It has no effect on intake airflow.
• D. It only affects exhaust temperature.

Answer: (A)

Larger exhaust pipe diameter reduces backpressure in the exhaust system, which lowers the resistance the engine faces when pushing out exhaust gases. With less backpressure, the pressure differential during the intake stroke is improved, making it easier for the piston to draw in air. This generally leads to better intake airflow, especially at higher speeds where exhaust flow is more pronounced. The idea that it has no effect or only affects exhaust temperature doesn’t fit the dynamics of gas exchange, and saying it worsens intake airflow would contradict how reducing restriction helps the intake stroke.