What RPM at 120 km/h Indicates a Good Engine?

[JakeLynn]

Currently, the displacement of mainstream engines is mostly around 1.5. For engines of this displacement, the RPM generally stays between 2200 and 3200. Naturally aspirated engines and turbocharged engines have different RPM values. Due to the boost from the turbine, turbocharged engines typically have lower RPM values compared to naturally aspirated engines. Depending on the vehicle class, the RPM at 120 km/h can be roughly categorized as follows: For A-class vehicles, priced between 100,000 to 150,000 yuan, the corresponding engine RPM at 120 km/h is 2500~3500 rpm. For A+ class sedans, the RPM at 120 km/h is around 2500 rpm. For B-class sedans, it is approximately 2000 rpm, and for C-class sedans, it is around 1800 rpm. Owners can match these values to their own vehicles. If your vehicle's engine RPM at 120 km/h exceeds 3500 rpm, it is definitely abnormal or may be quite old, and the owner should consider replacing it with a new car.

[OCassandra]

I usually drive a 1.5T car for my daily commute. When cruising at 120 km/h on the highway, I've glanced at the tachometer and noticed the RPM hovering around 2100-2300. The biggest advantage of low RPM is fuel efficiency – a long trip can save you half a tank of gas. I remember driving my friend's older car once, where the RPM shot up to 3000 at 120 km/h, and the noise was so loud it gave me a headache. Nowadays, newer cars come with more gears, like 9AT or even 10AT, making highway driving incredibly smooth. However, lower RPM isn't always better. Take my cousin's small-displacement turbocharged car, for example – if the RPM is too low, it lacks power during acceleration.

[DeAnthony]

As an experienced driver who has owned several performance cars, I think judging an engine solely by its RPM at 120 km/h is too one-sided. Naturally aspirated engines with larger displacements generally run at higher RPMs - my 3.0L V6 still delivers ample power at 2700 RPM on the highway. What really matters is the engine's performance in the commonly used RPM range. If it delivers smooth torque output and responsive acceleration between 2000-4000 RPM, it's a good machine. While turbocharged cars maintaining under 2000 RPM at 120 km/h is impressive, the exhilarating sound of high-revving naturally aspirated engines offers a different kind of pleasure. Ultimately, car selection should align with personal driving preferences.

[LeAndrew]

After more than 20 years of car repair experience, I've found that engine RPM at 120 km/h mainly depends on three factors: the number of transmission gears, final drive ratio, and engine torque curve. For regular family cars, 2000-2500 RPM is ideal, while Japanese CVT models can maintain around 1800 RPM. Excessively low RPM should raise concerns - I once encountered a case where ECU tuning forcibly lowered RPM, resulting in burnt clutch plates. German cars typically run about 300 RPM higher than comparable Japanese models, but their superior thermal efficiency means actual fuel consumption isn't worse. Any normal car exceeding 3000 RPM at this speed indicates excessive fuel consumption, suggesting potential transmission or drivetrain issues requiring inspection.