What is the most fuel-efficient engine speed?

[IkerFitz]

When the engine speed is between 3000-3500 RPM, it is the most stable for horsepower output. For long-distance high-speed driving, maintaining the engine speed around 2500-3000 RPM is the most fuel-efficient. From the perspective of engine working principles, lower speeds indeed consume less fuel than higher speeds. At lower speeds, the engine doesn't need to inject as much fuel to maintain high RPM, naturally saving fuel. Here are some details about fuel-efficient speeds: 1. Maintaining the optimal speed: The most fuel-efficient driving condition is steady straight-line driving. The most fuel-efficient speed for small-displacement vehicles is 60-80 km/h, while for medium-displacement vehicles it's 80-100 km/h. 2. "Most fuel-efficient speed" still depends on specific road conditions. Additionally, practices like not frequently braking, reducing load, and maintaining normal tire pressure can all contribute to fuel savings to some extent.

[McAlan]

In the car I drive, the most fuel-efficient RPM is usually between 2000 and 3000, as the engine runs most smoothly and has the highest combustion efficiency in this range. I've noticed that when the speed is between 80 to 100 kilometers per hour, maintaining fifth or sixth gear with the RPM just within this range results in the lowest fuel consumption. For example, on the highway, keeping a steady RPM in this zone can save a lot of fuel. Avoiding sudden acceleration and high gear at low RPM is important, as it can lead to carbon buildup and actually increase fuel consumption. In actual driving, different car models may vary; my economy car is most fuel-efficient at 2000 RPM, but my friend's SUV might need to be around 2500 RPM. Regular engine maintenance and keeping tire pressure at the correct level can also help save fuel. In short, finding the right RPM habit for your specific car is key, and observing the fuel consumption gauge while driving can help you gradually figure it out.

[LucasLynn]

I think there's no fixed number for the most fuel-efficient engine RPM. Generally, it's close to the maximum torque output point, around 2500 RPM for example. I've driven turbocharged cars that start being efficient at lower RPMs, while naturally aspirated engines might need higher RPMs. Related to this is the shift timing – for automatic cars, let the system choose the gear, and for manual transmissions, shifting up around 2000 RPM saves fuel. Speed has a big impact too – maintaining 2000 RPM in the efficient zone at 60 km/h helps avoid engine lugging or high-RPM fuel consumption. I usually pay attention not to overuse the AC or carry too much load, as these increase engine load and move it away from the fuel-efficient point. By connecting to the OBD port with a phone app, I can monitor real-time fuel consumption data to help adjust my driving.

[DelQuinn]

As a car enthusiast, I've found that the most fuel-efficient engine speed depends on the engine type. Four-cylinder compact cars achieve optimal fuel consumption between 1800 to 2200 RPM, while six-cylinder vehicles are most efficient around 2500 to 3000 RPM. Having driven both German and Japanese cars, I noticed German turbocharged engines are highly efficient and fuel-saving at low speeds, whereas Japanese naturally aspirated engines perform better at medium-high RPMs. Related driving habits include maintaining steady RPMs and avoiding frequent braking or acceleration. Keeping a stable 2500 RPM during highway cruising saves significantly more fuel compared to stop-and-go city driving. Modifications like rear wheel sets or lightweight components can help maintain the fuel-efficient RPM range. Regular throttle body cleaning ensures unobstructed air intake.

[KylieMarie]

I found that when driving a regular family car, the most fuel-efficient RPM range is between 1500 and 2500, especially when shifting gears at 2000 RPM with a manual transmission, which results in lower fuel consumption. For automatic transmission models, maintaining a steady drive in D gear naturally keeps the RPM within this range. In terms of speed, keeping at 2000 RPM while driving at 50 km/h in the city is efficient and fuel-saving, avoiding engine idling. It's recommended to use cruise control on highways to maintain a stable RPM. For maintenance, changing the engine oil and air filter on time helps keep the engine clean. Reducing air conditioning usage while driving and avoiding excessive vehicle weight can prevent higher RPM and increased fuel consumption. I shared these tips with my friends to help them save fuel.