How to change engine rotation speed by setEngineRotationSpeed?

Hi,

I know this is a bad practice.

But in my game, in some special situations, I want to operate the engine rotation speed to achieve special functions.

I called setEngineRotationSpeed before PxVehicleSuspensionRaycasts and PxVehicleUpdates, but the rotation speed did not change.

So, how to use setEngineRotationSpeed?