Turbocharged and naturally aspirated engines differ in fuel efficiency as follows: For engines of the same displacement, turbocharged ones consume far more fuel than naturally aspirated ones: Turbocharged engines require more fuel to participate in combustion to generate power. Therefore, while increasing air intake, the vehicle's electronic system will match the corresponding amount of fuel to inject into the engine for combustion. For cars with the same displacement, turbocharged engines have higher fuel consumption than naturally aspirated ones. However, in terms of power, turbocharged engines can produce stronger power, faster acceleration, and better climbing performance. Turbochargers only show advantages at high speeds: The power of a turbocharger comes from exhaust gases. When the engine itself is running at low speeds, the exhaust gas produced is relatively low, and the power is insufficient. At this point, the compression effect of the turbocharger is also poor, or it may not even be working. In such cases, there is no difference between a turbocharged engine and a naturally aspirated one, and no advantage exists. Under the same displacement, fuel consumption is theoretically similar. Vehicle condition is the core factor determining fuel consumption: If comparing vehicles with the same power output, turbocharged engines have an advantage in fuel consumption. This is because, theoretically, turbocharging can increase power by about 35%. For example, a 1.8T turbocharged engine can be equivalent to a 2.4L naturally aspirated engine—but only at high speeds. In real-world conditions, vehicle conditions are very complex. Factors such as traffic congestion, idling, low-speed driving, vehicle weight, and road resistance all directly affect fuel consumption, thereby offsetting the advantages that turbocharging might offer.
