Motor King38

The NSR King38: long can power for high-performance slot racing

When NSR launched its King motor line, the goal was clear: to provide club racers and demanding builders with a unit capable of performing at the limit with durable construction. The King38 (reference NSR3015) embodies that philosophy with 38,500 rpm and 310 g-cm of torque measured at 12V, figures that place it in the high-power range within the Italian brand's catalogue.

Main features

• No-load speed: 38,500 rpm at 12V
• Torque: 310 g-cm at 12V
• Can type: Long (long can)
• Brand: NSR (reference NSR3015)

The long can provides greater rotating mass and, in combination with the windings of the King38, generates a generous torque curve that translates into strong corner exits and high top speed. It is the type of motor that is noticeable from the first lap.

Recommended applications

The King38 naturally fits slot chassis that accommodate long can motors in sidewinder (motor parallel to the rear axle) or anglewinder (motor angled relative to the rear axle) configurations. Always check the dimensions of your chassis motor mount before installing any long can motor to ensure there is enough space.

Due to its characteristics, this motor is particularly suitable for:

• Club championships with longer tracks where top speed matters.
• Preparation builds in NSR cars or any chassis compatible with long can motors.
• Drivers looking to make a power leap from mid-range motors.

Behaviour and performance

A motor with 38,500 rpm at 12V is a high-rev unit: it responds quickly to the trigger and requires a guide, braid, and tyres in good condition to harness its full potential without losing grip. If you are going to use it in competition, check the condition of the braids and ensure that the transmission (pinion and crown gear) is correctly aligned and lubricated. A small amount of play in the drivetrain can translate into vibrations that reduce actual speed.

The torque of 310 g-cm ensures that the car does not lose power in the slow sections of the track, something that can be a weak point in purely high-speed motors. The King38 balances both registers well.

Usage recommendations

• Perform a gentle initial run-in (2-3 minutes at reduced voltage) to seat the brushes and extend the motor's life.
• Keep the collectors clean: a dirty collector increases electrical resistance and reduces actual performance.
• Combine the King38 with a gear ratio suitable for the circuit: technical tracks with many curves benefit from a shorter ratio; fast layouts allow for a longer transmission to take advantage of the rpm.
• NSR offers a wide range of spare parts and tuning accessories to keep the motor in perfect condition throughout the season.

Frequently asked questions

Is the King38 compatible with chassis from other brands?

In general, yes, as long as the chassis has a motor mount for long can motors with the appropriate dimensions. It is advisable to check the technical specifications of the chassis before purchase.

What is the difference between a long can motor and a short can motor?

The long can has a longer magnet, which typically allows for more torque and, depending on the winding, more rpm. The downside is that it takes up more space within the chassis, so not all cars are compatible.

What motor configuration is the King38 compatible with: sidewinder, inline or anglewinder?

The King38 is a long can motor that can be mounted in sidewinder (motor parallel to the rear axle) or anglewinder (motor angled relative to the rear axle) configurations, depending on the chassis design. It is not intended for inline configurations (motor perpendicular to the rear axle, in line with the car).

Do I need to run in the motor before using it in competition?

Yes. An initial run-in at reduced voltage for a few minutes helps to seat the brushes against the collector, improves electrical contact, and extends the motor's lifespan. It is a simple step that makes a difference in long-term performance.

What pinion and crown gear do you recommend for this motor?

The optimal gear ratio depends on the layout and the car. NSR offers a wide catalogue of pinions and crown gears in different modules so you can adjust the transmission for each circuit. Check the specific recommendations for your setup.

The NSR King38 (NSR3015) is a long-can slot car motor delivering 38,500 rpm and 310 g-cm torque at 12V. Designed for high-performance slot racing, it suits sidewinder and anglewinder setups in 1/32 scale competition cars. A top choice for club racers and serious builders looking for a reliable, powerful NSR motor upgrade.