Larger diameter exhaust pipes will help improve the engine's ability to increase intake airflow.

• A. True
• B. False
• C. Not specified
• D. Not applicable

Answer: (A)

When the exhaust path is less restrictive, the engine breathes more easily. A larger diameter exhaust reduces backpressure, letting exhaust gases escape more freely and lowering the pressure that builds up in the exhaust ports. This helps the upcoming intake stroke by creating a stronger pull for fresh air and improving scavenging—the process where the momentum of exiting exhaust helps draw in the next charge. In short, less backpressure means the engine can fill the cylinders more effectively, which improves intake airflow. Note that very large pipes can reduce exhaust gas velocity at some RPM ranges, which can hurt scavenging then, but overall increasing diameter tends to enhance the engine’s ability to increase intake airflow.