Probably drives a huge lifted truck, and will be wearing a black famous star shirt, with white sunglasses and a white hat.
He is called a brap because he probably rides a quad or a dirtbike, and those machines make this noise.
As well as this, it was used by bikers in the 80's as reference to the sound of their engines.
Now most notably used in the UK by chavs who get to excited by anything and everything.
2 - this engine is one hell of a mother, braaaaaaaaaaap
3 - init bruv, brap!!