Which part would you say is edited in? To me it looks like he just put a moving river there, retextured it to lava, and made the particles orange. If he wanted even more fire, he can simply light the car on fire too, but it all looks in-game to me.
Looks like the ''splash'' you get when you fall into water but just coloured orange, then it disappears like a splash and the current particles are there but also in orange.
