My hobbies aren't as expensive as cars, but I'm heavily into Lego and board games. Given that a lot of games trend $50+ (we're talking Eurogames here, not Monopoly and LIFE) and Lego is, well, Lego, it's very easy to spiral out of control. I deal by making sure I thoroughly research purchases (no impulse buys), buy used when I can find stuff in good shape, hunt for deals, etc. I also make sure my other hobbies don't cost much, if anything. (For example, I'm a big reader but all books come from the library.)
Basically, I try to be a smart hobbyist and buy only what I know I'll enjoy and get the best price I can on it. I also cut expenses in areas I don't care about to fund the hobby thing. No TV, cheap phone, etc.
It's worth noting that I turned the board game thing into a side hustle by writing reviews. So I sometimes get review copies of games which helps a lot.
Maybe look into seeing if there's a way to monetize the hobby, even if just a little bit. You don't want to kill your joy by turning it into a job, but maybe there's some way, like working on other people's cars or, as pp mentioned, teaching. Or, heck, working at the track in the food stand (if they have those).