In a gasoline engine, what would cause a lower power output, in relation to the intake and exhaust system?

In a gasoline engine, what would cause a lower power output, in relation to the intake and exhaust system?

• A. Leaking exhaust manifold
• B. Restricted intake or silencer
• C. Faulty fuel injector
• D. Ignition timing advanced

Answer: (B)

Power output in a gasoline engine hinges on how well the engine can breathe—air going in and exhaust going out. When the intake path is restricted, less air can fill the cylinders on each cycle. Since there’s less air (and thus less oxygen) to burn with the available fuel, the combustion energy drops and so does the engine’s usable power, especially as RPM climbs and more air is required. A silencer or other intake restriction directly adds resistance and drops the pressure that helps fill the cylinders, reducing volumetric efficiency and peak power. Other issues affect power in different ways. A leaking exhaust manifold can disturb exhaust flow and backpressure, but it isn’t the direct cause of reduced intake-driven power. A faulty fuel injector changes fuel delivery, not the air path. Ignition timing that’s too far advanced or retarded changes combustion timing, not the airflow through the intake/exhaust system.

Power output in a gasoline engine hinges on how well the engine can breathe—air going in and exhaust going out. When the intake path is restricted, less air can fill the cylinders on each cycle. Since there’s less air (and thus less oxygen) to burn with the available fuel, the combustion energy drops and so does the engine’s usable power, especially as RPM climbs and more air is required. A silencer or other intake restriction directly adds resistance and drops the pressure that helps fill the cylinders, reducing volumetric efficiency and peak power.

Other issues affect power in different ways. A leaking exhaust manifold can disturb exhaust flow and backpressure, but it isn’t the direct cause of reduced intake-driven power. A faulty fuel injector changes fuel delivery, not the air path. Ignition timing that’s too far advanced or retarded changes combustion timing, not the airflow through the intake/exhaust system.