You go to the myriads of car communities and systematically promote your content for Nurburgring. It’s a niche site, and by the OP’s description we can safely assume that it’s quite usable since he’s been already approached by a sponsor. And since this is a site about a specific car circuit you just go to the actual place, or make an arrangement with the organizers to promote your site. Give a leaflet, or build an accompanying mobile app.

I'm not saying that circumventing Google is the easiest thing in the world, or the cheapest, but it's not mission impossible either. I didn't find Hacker News from Google, not the dozens of other tech communities I'm following.