WATCH: Biggest Rotary Engine In The World Has 12 Rotors

We're big fans of unorthodox engine designs, and the insane 12-rotor rotary engine that Rob Dahm has just featured on YouTube is nothing if not unique. It's the only engine of its kind in the world, and no major automaker has ever been brave enough to build one.

The man behind this engine is Tyson Garvin from Apex Manufacturing and Design, and he took Dahm - a fan of rotary engines who often races his four-rotor Mazda RX-7 - through the thinking behind creating the 12-rotor mill. Remember that Mazda's rotary engines in both the stock RX-7 and the later RX-8 only had two rotors.

But what makes a rotary engine so special in the first place? There are a few aspects, but one of the primary features of it is that instead of reciprocating pistons that create a rotating motion in a conventional engine, rotary engines have a triangular-shaped rotor that spins on an axis. They also have no valves which contributes to far fewer moving parts.

Garvin explained that in building engines for speed boats, he and his team had done pretty much all they could with a Chevy big block power plant, whereas the scope for a rotary design was larger.

"We started measuring a big block Chevy and seeing how many rotors [we could] fit in that spot," said Garvin. "In the end, we came up with this design that is the exact shape of a big block Chevy. I basically made it to replace my boat engine."

When put on a dyno, this 12-rotor rotary engine made around 800 lb-ft of torque at just 2,000 rpm - from a naturally-aspirated engine. And that's just a taste of what the engine can do, as it'll be able to spin all the way to 10,000 rpm.