From BeamNG

The Friction Clutch (device name "frictionClutch") is a model of a sprung friction clutch. It improves on the old viscous clutch model from pre 0.7.2 by allowing angular locking of the engine to the powertrain, instead of constant slippage. In a Powertrain, it should be connected to a combustionEngine or electricMotor, and have a manualGearbox connected to it.

Jbeam Properties

Name Type Optional Default Value Description
lockSpring number true Autocalculated This value is calculated by looking at the downstream inertia in the powertrain and applying the most possible spring. Not recommmended to change. Going higher can cause instability.
lockTorque number true Autocalculated The torque limit after which the clutch will slip. This value is calculated by finding the torque required to stop the engine from redline in 1 second with full power. Not necessary to change unless you want very high peak forces from the clutch.
lockDamp number true =lockSpring/1000 A small amount of damping for stability. Not necessary to change.
clutchStiffness number true 1 This number can soften or stiffen the clutch angle integration. Not recommended to change.
coolingCoef number true 1 How effectively the clutch transmits heat to the bellhousing. Increase for better cooling.
maxClutchTemp number true 500 Maximum temperature of clutch (°C) before it is irreparably damaged and can no longer transmit torque.
warningTemp number true 200 Temperature of the clutch (°C) at which an onscreen warning is displayed.
maxSafeClutchTemp number true 300 Temperature of the clutch (°C) at which it begins to lose efficiency and begins slipping.
additionalEngineInertia number true 0 Sets the inertia of the clutch in kg*m^2. This will be added to the inertia of the engine.


Here is an example of the required powertrain section, along with the additional section for the properties.

    "powertrain": [
        ["type", "name", "inputName", "inputIndex"],
        ["frictionClutch", "clutch", "mainEngine", 1],
    "clutch": {},//you dont need to put anything here ;)