What is the difference between naturally aspirated and turbocharged engines in cars?

[LeEverett]

The differences between naturally aspirated and turbocharged engines in cars are as follows: 1. Different engine structures: A car's turbocharged engine adds a turbocharging device to the traditional engine, while a naturally aspirated engine does not have a turbocharging device. 2. Different power outputs: Turbocharged engines of the same displacement have a power performance that is more than 40% higher than naturally aspirated engines, meaning that the same engine can output greater power and stronger explosive force after being turbocharged. 3. Different maintenance costs: Turbocharged engines have stronger power, which leads to faster performance degradation compared to naturally aspirated engines, and higher maintenance costs in the long run.

[LeMicah]

I've driven quite a few cars, and to be honest, naturally aspirated and turbocharged engines feel completely different. A naturally aspirated engine is like an old chef simmering soup—air flows into the cylinders on its own, and the whole process is as smooth as Dove chocolate. But a turbocharger is like adding a windmill to the engine's rear, where exhaust gases spin the blades to force-feed air into the cylinders, allowing even a small-displacement engine to deliver big power. During test drives, I noticed that turbocharged cars can unleash full torque at just 1,800 RPM, while naturally aspirated engines need to rev past 4,000 RPM to really come alive.

[OBrooke]

During car repairs, I discovered that a turbocharger is essentially giving the engine a ventilator. The exhaust turbo spins wildly to drive the intake turbo, forcing air into the cylinders like a pump. This allows a 1.5T engine to deliver more horsepower than a 2.0L naturally aspirated one, though fuel consumption in city driving can be 1.5 liters higher. However, turbocharged engines tend to run at higher coolant temperatures. Last time, I saw an owner who forgot to change the turbo coolant, resulting in the intercooler getting warped from overheating. Repairs for turbocharged engines are much more expensive than for naturally aspirated ones.

[SanJesse]

The differences in materials are quite noticeable. Turbocharged cars require an entire forced induction system mounted externally to the engine, and the exhaust pipes must be made of heat-resistant stainless steel. During operation, the turbine blades can reach speeds of up to 200,000 RPM, similar to aircraft engines. Naturally aspirated engines have a much simpler structure—just open the cylinder head and you'll see the camshaft and valves, with routine maintenance involving only oil and filter changes. However, the newly developed Miller-cycle naturally aspirated engines are also quite fuel-efficient, like Toyota's 2.0L engine achieving a thermal efficiency of 40%.