Rob Dahm’s Tri-Turbo, 12-Rotor Engine Is Alive

Back in 2023 rotary guru Rob Dahm showcased a one-of-a-kind engine: a custom-built 12-rotor mill, made years ago by a person named Tyson Garvin. Dahm has spent the last year and a half, bringing it back from a state of disrepair … while also making some upgrades. When you have an engine as crazy as this, you can’t just leave well enough alone.

We checked in to see how Dahm was doing. And things are going well. The 12-rotor is alive, and by the time everything is set, Dahm is hoping for 5,000 horsepower. Yes, 5,000.

His YouTube channel offers several videos on the build, but the one featured here will stop your heart. Without going into excessive detail, the engine is designed to run on methanol and uses three turbochargers. That’s because the engine is set up in three banks, each with four rotors. Only two of those turbos were bolted up for the all-important first start, clearly visible on each side. The third turbo bolts to the collector exiting under the dual throttle bodies. For testing purposes, he wanted easy access to the front and the turbo would’ve been in the way.

Just getting the engine to turn over was a challenge. The dual starters weren’t spinning fast enough, so he tied several car batteries together for more power. It’s only a temporary measure; a custom starter capable of spinning the 12-rotor fast enough is in the works. But for reasons we can absolutely understand, Dahm didn’t want to delay this moment any longer.

We don’t have words to describe the sound. The shaking camera arguably provides the best narrative of this project. It’s far from perfect, but it runs and it even settled into an idle. Work is ongoing, but Dahm has plans to eventually get this mega-rotary into a car.

God help us all when that happens.