Speak with Wizzle Brassbolts in the Shimmering Flats.
Have you met the Brassbolts brothers? They're over in the Shimmering Flats, in Kalimdor, racing their rocket car against the goblins. They usually win which is no surprise--the goblin car blows up so much it barely ever crosses the finish line!
But even then, the Brassbolts brothers are always looking for new ways to make their car go faster, and Wizzle told me he needs a very rare component for his next experiment.
He probably needs help getting that part. Speak to him and find out.