The first digit on the left side of the number at the back of a BMW indicates the series. For example, 320 means this car belongs to the 3 Series (currently, sedan series include 1 Series, 3 Series, 5 Series, and 7 Series, with other series under development. SUV series include X1, X3, X5, and X6, with other models under development. Hybrid or electric models start with 'i,' such as the upcoming i3. 'Z' denotes sports cars, and 'M' represents high-performance sedans. Adding 'GT' after the number indicates a hatchback or touring version of that series). The second and third digits represent the engine displacement. The final letter 'i' stands for electronic fuel injection. For example, BMW 530L means it's a 5 Series, with a 3.0-liter engine, long-wheelbase version, and a gasoline engine. Originally, the numbers representing engine displacement were very close to the actual displacement. However, with continuous model updates and market demands, some models later increased the engine displacement but still retained the old model number, such as the 540i, which has a 4.4-liter engine. The engine displacement has started to be 'smaller' than the model number, which is a little secret of BMW manufacturers. This so-called secret is that BMW has been using more turbocharged engines in recent years. For example, the new 740Li uses a 3-liter twin-turbocharged engine, and the 750Li uses a 4.4-liter twin-turbocharged engine. Domestic BMW 523Li and 325 models both use a 2.5-liter inline 6-cylinder engine. The 650 uses a 4.8-liter engine. Although the engine displacement is 'smaller' than the model number, the power performance remains robust. The final letters: 'L' stands for the long-wheelbase version, 'i' represents a gasoline engine, and overseas BMW models may have 'D' as a suffix, which denotes a diesel engine.
