This Is What a One-Rotor Turbo Miata Making 155 HP Sounds Like

Maybe you’ve heard about Rob Dahm’s insane 12-rotor engine that runs three turbos? Well, this is kind of like the opposite. It’s his single-rotor Miata, which he’s been building and featuring on his YouTube channel for the past year or so. Dahm got it on the dyno recently, and the result was surprisingly good. In fact, it’s rowdy enough to grenade the rear diff if you try hard enough.

This build has been one of the best to follow on YouTube in a minute. You could spend hours watching all the one-rotor videos so far, but what you need to know is that the engine is made almost entirely of billet aluminum, weighing right around 70 pounds. An internally wastegated Garrett GBC-22 turbo helps propel it, and it has a 3D-printed intake manifold since you can’t just fine those lying around.

Dahm has been driving the single-rotor Miata for the past five episodes. Tuning it has been a labor of love, as it’s taken quite a bit of work to smooth out the engine operation and whatnot. It’s still dumping a ton of fuel into the combustion chamber, but hey, it’s getting there.

After rolling into Westech Performance, the crew strapped the Miata down for a series of test runs. It managed a best result of 155 horsepower and 136 lb-ft of torque, which is fantastic when you consider that this is a totally scratch-built project with very little displacement. The one-rotor has the potential to make even more power once Dahm figures out the nagging fuel issue.

Turbo 1 Rotor Miata hits the Dyno!

Ultimately, this build isn’t quite polished, but you can bet it will be before long. Dahm has a good idea of what’s going wrong, with boost creep from the internal wastegate causing sudden spikes up to 22 psi that appear to be blowing fuel into the oil catch can. Once he fettles with the clearances and gaps inside the engine and rectifies the turbo situation, it ought to be a strong runner.

I respect it one way or another. I could never put something together like this, and honestly, who cares how much power it makes? A functional turbo one-rotor is impressive. The fact that it can power a Miata down the highway is icing on the cake.

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