Torque Curve in VehicleMovement (Wheeled Vehicle) does not seem to work at all

One solution is to change the default torque values in source files and recompile ue.

It should be stored under \Engine\Source\ThirdParty\PhysX\PhysX_3.4\Include\vehicle\PxVehicleComponents.h

PxVehicleEngineData()
    :     mMOI(1.0f),
        mPeakTorque(500.0f),  <---
        mMaxOmega(600.0f),  <---
        mDampingRateFullThrottle(0.15f),
        mDampingRateZeroThrottleClutchEngaged(2.0f),
        mDampingRateZeroThrottleClutchDisengaged(0.35f)
{
    mTorqueCurve.addPair(0.0f, 0.8f);
    mTorqueCurve.addPair(0.33f, 1.0f);
    mTorqueCurve.addPair(1.0f, 0.9f);

    mRecipMOI=1.0f/mMOI;
    mRecipMaxOmega=1.0f/mMaxOmega;
}