What is the equivalent car engine displacement for 400cc?

[VanAnnie]

400cc equals 0.4 liters of displacement, where "400CC" refers to the exhaust volume of a motorcycle engine's combustion chamber. CC is the volume unit for cylinder displacement, with 1CC equivalent to 1ml. According to China's relevant standards, different displacements correspond to the following vehicle types: 30CC and below are defined as fuel-powered bicycles. A type of bicycle includes a frame, front wheel, rear wheel, a bottom bracket set at the lower end of the frame, and an engine. The bicycle frame is composed of interconnected hollow tubes containing fuel oil. The front and rear top parts of the frame are equipped with fuel filling holes and air release holes, respectively, and an oil pipe connects the lower part of the bicycle frame to the engine. For motorcycle engine daily maintenance, the following methods can be used: Use lubricating oil of appropriate quality grade. For gasoline engines, choose SD--SF grade gasoline engine oil based on the additional devices of the intake and exhaust systems and usage conditions; for diesel engines, select CB--CD grade diesel engine oil according to mechanical load, with the selection standard not lower than the manufacturer's requirements; Regularly change the oil and filter. The quality of any grade of lubricating oil will change during use. After a certain mileage, performance deteriorates, leading to various engine problems. To avoid malfunctions, change the oil regularly based on usage conditions and maintain an appropriate oil level; Oil passes through the fine pores of the filter, trapping solid particles and viscous substances in the oil. If the filter is clogged and oil cannot pass through the filter element, it may rupture the filter element or open the safety valve, allowing oil to bypass through the bypass valve, bringing contaminants back to the lubrication area and accelerating engine wear, intensifying internal pollution; Regularly clean the crankcase. During engine operation, high-pressure unburned gases in the combustion chamber.

[DeJasper]

I think 400cc is equivalent to a 0.4-liter engine displacement in cars, which is quite common in motorcycles. For example, some mid-sized motorcycles use this displacement, offering smooth riding but generally modest power. However, in the automotive field, 0.4 liters is too small. Nowadays, the smallest displacement cars typically start at 0.6 liters or more, like Japanese Kei cars such as the Suzuki Alto with 660cc, while regular cars like the Honda Fit have at least 1.0 liters. This is because car engines need to propel heavier bodies and carry loads—too small a displacement may result in sluggish acceleration, difficulty climbing hills, and risky highway overtaking despite being manageable in city driving. Engines that are too small lack sufficient horsepower, affecting the driving experience. That said, if well-designed, small-displacement engines can be fuel-efficient in micro city cars, though such applications are rare in practice.

[ColinDella]

I believe 400cc equals 0.4 liters, which is considered extremely small in terms of automotive displacement. I've driven some older microcars with displacements around 800cc, and by comparison, 0.4 liters is even more compact with limited power output, only suitable for short commutes. Most modern cars start from 1.0 liters, offering stable power and effortless load capacity, while 400cc converted is too small, resulting in noticeable vibrations and slow acceleration during daily driving. A 400cc displacement might be acceptable for motorcycles, but cars generally require larger engines to handle road challenges. Occasionally, there are experimental small cars attempting this displacement, but it's mostly impractical. While smaller displacements may offer better fuel efficiency, safety and reliability become concerns.

[SanHector]

I understand that 400cc is equivalent to a 0.4-liter displacement, which is too small in the automotive world. The smallest engine for a regular car is typically at least 0.6 liters. While 400cc engines are common in motorcycles, they are too weak for cars, resulting in low horsepower output and difficulty in carrying loads. The practical driving experience shows a significant gap—it might be acceptable for urban commuting but struggles on long-distance trips or uphill climbs. Modern cars rarely use such small displacement engines.