2 or 3 motorbikes pulling up to a stop light, revving their engines loudly to show everyone just how large their exhaust tips are, and then driving away. Sorry, i don't know make or model of the bikes.
With resemblance to the sound of an engine, this sound can be used with various different mechanical objects in mind. This sound was bounced into 24bit, 48hz, interleaved audio. This sound was synthesised using a digital synthesiser.