FC.Dyno is a benchtop performance testing system for HO slot cars. It shows the voltage delivered to its rails and the car's speed while the wheels are turning. After the run, you can review the highest speed, acceleration, and normalized torque values recorded for that test. This guide explains setup, the displays, the MODE button, diagnostic mode, and how to make useful comparisons.
Use a 12V to 27V regulated DC supply and begin every test at a voltage appropriate for the car and motor.
Quick start
- Set the power supply to a low voltage and check its polarity and connections before powering FC.Dyno. Follow the input rating marked for your unit.
- Place an HO car on the steel rails with its drive wheels centered on the roller. Check that the tires and roller are clean and the wheels turn freely.
- Increase the voltage gradually. The upper display shows rail voltage; while the car runs, the lower display shows speed in MPH.
- Bring the car to a stop. Press MODE to review the recorded maximum speed, acceleration, and normalized torque for that run. The segment indicator at the left of the lower display identifies the selected value.
- Reduce the supply voltage before removing the car. Repeat the test under the same conditions when comparing cars or adjustments.
What you need
The FC.Dyno unit includes its steel test rails, roller, two displays, and MODE button. You also need a suitable regulated DC power supply and an HO slot car. The power supply, controller, and car are not included.
Connect power and position the car
Turn the supply down before making connections. Verify polarity, secure the connectors, and use a voltage appropriate for the car you are testing. The upper display reports the actual voltage reaching the FC.Dyno rails; it may differ from a setting shown on the supply or controller.
Place the car so its pickup contacts touch the steel rails and its drive wheels rest properly on the roller. Center the car and check that the chassis, gears, tires, and other parts do not catch on the Dyno. The steel rails also let you compare cars in a setup that retains the magnetic interaction of an HO track.
Keep fingers, loose clothing, tools, and small objects clear of the rotating wheels and roller. Start at a low voltage and increase it gradually. Stop immediately if the car vibrates excessively, overheats, makes unusual noises, or runs unstably.
Understand the displays
- Upper display — rail voltage: Shows the voltage supplied to the test rails throughout operation.
- Lower display while the car runs — live speed: Shows the current speed in miles per hour (MPH).
- Lower display after the car stops — test results: Shows a recorded maximum. Press MODE to move between speed, acceleration, and normalized torque.
Three small segments at the left of the lower display indicate which result you are viewing:
- Upper indicator: Maximum speed, in MPH.
- Middle indicator: Maximum acceleration, in meters per second squared (m/s²).
- Lower indicator: Maximum normalized torque, in gram-centimeters (g·cm).
The torque value is a normalized performance estimate derived from the Dyno's measurements. Use it to compare tests made under the same conditions; it is not a direct measurement of motor shaft torque.
Use the MODE button
After a run, press MODE to cycle through maximum speed → maximum acceleration → maximum normalized torque. Watch the upper, middle, or lower segment indicator to confirm the selected result. When you start another test, treat it as a new run and record any earlier values you want to keep; FC.Dyno is not a long-term data logger.
Use diagnostic mode
Diagnostic mode shows the roller's rotational speed in RPM (revolutions per minute). It can help check the optical measurement system when a speed value seems unusual.
- Turn FC.Dyno off.
- Press and hold MODE.
- Turn the unit on while continuing to hold MODE.
- Release MODE after startup. Read the roller RPM in diagnostic mode.
For regular car testing, turn the unit off and start it again without holding MODE. An RPM reading describes the roller's rotation; it is not an MPH result.
Compare cars and interpret results
Test cars at the same rail voltage and use the same placement, tire condition, roller condition, and test procedure. Let each car stabilize, then repeat the run if a difference is small. FC.Dyno can help you compare cars or check the effect of motor work, lubrication, gearing, tires, magnets, and drivetrain changes.
Speed on a Dyno is a bench result, not a lap time or a guarantee of track performance. Grip, corners, weight, magnetic traction, controller behavior, and the condition of the track can change how a car performs in a race. The most useful conclusions come from comparing changes under repeatable conditions.
Troubleshooting
The car does not run or the voltage display is unexpected
Check the power supply setting, polarity, cable connections, pickup contact with both rails, and the controller or connector arrangement used with your unit. Do not increase the voltage merely to overcome a poor connection.
The roller turns but the speed reading is missing or erratic
Check that the drive tires make steady contact with the roller and that nothing interferes with its rotation. Clean the tires and roller, then test again at a moderate voltage. Use diagnostic mode to see whether the roller RPM follows changes in speed.
Results differ between otherwise similar runs
Compare the voltage shown on the upper display, not just the supply setting. Recenter the car, clean the roller and tires, and repeat the same acceleration procedure. Brief wheelspin or unstable contact can affect peak readings.
MODE shows RPM instead of the usual results
The unit started in diagnostic mode because MODE was held during power-on. Turn it off and start it again without pressing MODE.
Frequently asked questions
Does FC.Dyno need a computer or FC.Platform?
No. FC.Dyno is a standalone test instrument. FC.Platform 2.0 does not currently provide a Dyno test screen or import these measurements.
Does the lower display show live acceleration and torque?
While the car runs, the lower display shows live speed. Stop the car and use MODE to inspect the maximum acceleration and normalized torque recorded during the run.
Is normalized torque the motor's measured shaft torque?
No. It is a calculated comparison value in g·cm. Compare it between repeatable tests on the same Dyno, rather than treating it as a laboratory torque measurement.
Why is my Dyno speed different from my speed on the track?
The roller test and a driven car on a complete track are different conditions. Use FC.Dyno to compare setups consistently, then confirm a change with laps on your track.
Care, safety, and support
Reduce voltage before removing a car. Do not leave it running unnecessarily at high speed or voltage, and disconnect the supply when testing is finished. Keep the rails, roller, and pickup contacts clean. Never exceed the voltage recommended for the car or motor.
If you need help, email fc.slotcars@gmail.com. Include the car and motor, supply voltage and polarity, what each display shows, and a short video of the test or diagnostic reading.
Fernán Castillo
FC Slot-Cars