Every engine has a redline, which marks the maximum revolutions per minute (rpm) it can handle. Going beyond this redline can lead to serious engine damage. This is particularly important in manual-transmission cars, where you control gear shifts to keep the engine below the redline.
When you shift gears in a manual car, you use the gear shift and clutch to ensure the engine stays within safe rpm limits. The clutch connects the engine to the transmission, and gear shifts control the engine speed through different ratios.
Even within the safe rpm range, engines have a narrow band where they perform best in terms of torque and horsepower. Shifting gears helps keep the engine in this optimal performance range whenever possible. However, this range is limited to a specific gear ratio, meaning the engine performs best at a particular speed.
To address this limitation, continuously variable transmissions (CVTs) were developed. They can adjust gear ratios to keep the engine near its optimal performance range at different speeds. Although CVTs were initially less efficient and cost-effective than traditional transmissions, advancements have made them more popular.
Regardless of the transmission type, the key is to avoid exceeding the redline to protect your engine’s health.