In RC car upgrades and modifications, replacing the motor with a brushless one is one of the most discussed topics among hobbyists. Compared with brushed motors, brushless motors offer clear advantages in efficiency, power output, and durability. However, what most players really want to know is: how much speed can actually be gained after switching to a brushless motor? There is no single fixed answer, as the result depends on the vehicle setup, power system matching, and driving conditions.
Key Differences Between Brushed and Brushless Motors
Brushed motors rely on brushes and a commutator to operate. They are simple in structure and relatively low in cost, but they suffer from higher energy loss, noticeable heat generation, and limited efficiency and maximum RPM. Brushless motors, on the other hand, use an electronic speed controller (ESC) for commutation and eliminate brush friction, resulting in higher efficiency and more direct, stable power output.
Because of these structural differences, brushless motors generally deliver higher RPM and stronger sustained output than brushed motors under the same voltage, forming the foundation for speed improvement.
Typical Speed Increase After Switching to a Brushless Motor
In real-world upgrades, moving from a standard brushed system to an entry-level brushless system usually results in a top speed increase of about 20% to 40%. For example, an RC car with a top speed of around 30 km/h may reach 40 km/h or more after the upgrade.
When combined with a high-KV brushless motor, a higher-performance ESC, and an upgraded battery, speed gains can exceed 50%. However, this level of improvement typically requires a complete system upgrade rather than replacing the motor alone.
The Role of Motor KV in Speed Improvement
KV refers to the motor’s no-load RPM per volt. A higher KV rating means higher theoretical RPM and greater top-speed potential. However, higher KV is not always better. High-KV motors place greater demands on battery discharge capability, gear ratios, and cooling.
If only a high-KV brushless motor is installed without upgrading supporting components, the actual speed increase may be limited, and issues such as overheating or power drop may occur.
The Impact of Battery and ESC on Final Speed
The performance of a brushless motor depends heavily on the battery and ESC. High-discharge lithium batteries provide stable current output, allowing the motor to maintain power at high speeds. The ESC is equally critical—if its current capacity is insufficient, it will restrict motor performance and limit top speed.
Only with proper matching of motor, ESC, and battery can the full speed potential of a brushless system be realized.
Importance of the Drivetrain and Overall Vehicle Tuning
Even with a high-performance brushless motor, unreasonable gear ratios, inefficient drivetrain components, or insufficient tire grip can significantly limit speed gains. Adjusting pinion and spur gear ratios and upgrading bearings and tires often make the speed improvement from a brushless motor much more noticeable.
How Driving Conditions Affect Perceived Speed Gains
On straight tracks or high-speed circuits, the increase in top speed from a brushless motor is most apparent. On technical tracks with many corners or off-road terrain, improvements in throttle response and acceleration are often more noticeable than gains in top speed. As a result, some drivers feel the “speed increase is not obvious,” when in reality the track conditions prevent the car from reaching its maximum speed.
Conclusion
Overall, switching an RC car to a brushless motor typically results in a speed increase of 20% to 50%, depending on the motor KV rating, battery, ESC, drivetrain, and overall vehicle setup. The advantages of brushless motors go beyond top speed—they also deliver better efficiency, acceleration, and consistency. Only with proper system matching and tuning can a brushless motor fully unlock its speed potential and provide a comprehensive performance upgrade for an RC car.