Racing engines are a whole different world. They’re insanely powerful, insanely revvy, and usually seem to be either way too big or way too small. This one is firmly in the latter camp, because it’s a 4.0L four-cylinder. It’s the size of a small house, makes about 375 horsepower per liter, and costs just a shade less than a 911 Turbo. Oh yeah–it’s also called Thor.
The Drive got in touch with the Finnish nutters who built this thing, and they learned that the primary benefit of using a 1,500-horsepower four-cylinder is that even being as big as it is, it’s got a tremendous weight advantage over a comparable V8. This is a boon because in some race series, minimum weight limits mean that putting a lot of effort into designing a featherweight engine doesn’t have a benefit and might not even be allowed. In non-limited classes, however, a lighter four-cylinder can produce similar performance numbers while shedding pounds.
Thor also shirks expectations about the revviness of such a large engine with so few cylinders; the designers say the engine can run up to 10,000 RPM without exploding, but they’re playing it safe and running it around 8,500 in its upcoming first race.
You can check out more of the build process on YouTube, where Elmer Racing has documented some of the process: