For many people looking for new cars, a note in most engines classifies them as NA, naturally aspirated engines, or FI, forced induction engines. A naturally aspirated engine takes air from a single intake and cycles it through the engine, while a forced induction engine uses suction to scoop in large amounts of air to increase performance or power.
Naturally aspirated engines are fairly simple. Air is taken in through a single or dual intake box and is sent into the engine. The amount of air sent in is regulated by a throttle body determining how much of that air is sent into the engine. It is limited, though, by the amount of air in the atmosphere. Even if the car has a high amount of efficiency, this can limit the total output and efficiency of the engine as it will force the car to run at high RPMs at higher speeds.
A forced induction engine uses a vacuum funnel of air sent directly into the engine. This excess of air causes the engine to work at a higher power output. Forced induction engines are created by two different methods: turbocharging and supercharging.
Turbos use excess waste sent from the exhaust manifolds to create a vacuum of air being sucked into the car. This produces what is called ẗurbo lag, which is the wait in between the exhaust gasses spinning the turbine in the engine until it is spooled up and begins sending air into the engine while this creates a higher efficiency as it decreases the effort needed by the engine too much intake in one moment can cause a catastrophic engine failure
Superchargers, on the other hand, run from the timing chain of the car. While it decreases the total power produced from the engine and will decrease the maximum output, it gives instantaneous speed and power.
With the increasing availability and knowledge on how to increase efficiency. forced induction engines have become more available and reliable, due to their abilities to produce more power in sports cars and to increase fuel economy in smaller engine cars.
