The Dementor car with sound is controlled by a on/off switch on the bottom of the car. It only works conventional. Doesn't work with the remote.
As for the lion chef engine (no bluetooth), I have a problem pulling extra cars. I have the addon cars, two Dementor cars. It doesn't work well. I am really hoping they will upgrade and make a Lionchef +2 like they did with the polar express.