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When you think of rotary-engine cars, the first thing that comes to mind is undoubtedly the Mazda RX-7. For good reason, too. It’s a legendary sports coupe with a unique engine and a full-blown cult following. That said, the RX-7 does a great job of overshadowing its sporty rotary cousin, the Mazda Eunos Cosmo. Though it’s not a full-blown sports car, it has an even more unique engine than the RX-7. Let’s talk about it!

What engine does a Mazda Eunos Cosmo have?

The 20B three-rotor rotary engine with sequential twin turbocharger system from the 1990s Mazda Eunos Cosmo
20B three-rotor engine | Mazda

Like the RX-7, the Eunos Cosmo uses a rotary engine. However, the RX-7 uses a two-rotor engine. Depending on which generation RX-7, you’ll find either a naturally aspirated or sequential turbocharged two-rotor engine. Second-gen and third-gen RX-7 models (as well as the Mazda RX8) used Mazda’s 13B rotary engine. The Eunos Cosmo, though, uses a 20B.

The 20B found in the Mazda Eunos Cosmo is unique in that it’s the only three-rotor engine Mazda ever put in a production vehicle. If having the third rotary isn’t enough to excite you, perhaps the sequential twin-turbocharger system will! It switches from a smaller turbocharger to a bigger one as the RPM increases to minimize turbo lag and maximize power output.

front 3/4 view of a red Mazda Eunos Cosmo sports coupe, the rare and forgotten rotary car
Mazda Eunos Cosmo | Mazda

Auto-Data reports that the Mazda Cosmo made 280 horsepower. However, if that number seems suspicious, it’s likely because you’re familiar with the gentlemen’s agreement. In the ‘90s, Japanese manufacturers agreed that no cars would make more than 280 horsepower for safety reasons. As many know, that agreement only went as far as spec sheets on paper. Likely, the Eunos Cosmo packs quite a bit more punch than that.

In addition, the on-paper torque output is 296 pound-feet. This power output, alongside the high-revving rotary engine and minimal lag from the sequential turbocharger system, certainly means the Cosmo is a blast to drive.

Was the Mazda Cosmo sold in the U.S.?

Tan leather interior of a 1990s Mazda Eunos Cosmo
Eunos Cosmo Interior | Mazda

Unfortunately, the U.S. did not get the Mazda Eunos Cosmo. That being said, they are now over 25 years old. So, one could certainly legally import one into the U.S. Sure, it’s not the JDM sports car staple that the RX-7 is. It is, however, extremely unique. You don’t see a lot of them in the U.S.

There is one big problem for automotive enthusiasts, though. The Eunos Cosmo was available only with an automatic transmission. Overall, this is one of the most slept-on Japanese classics out there.

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Braden Carlson

Braden Carlson has been an automotive journalist since 2019 and joined MotorBiscuit in 2022. As a self-professed Aerospace Engineering dropout, Braden has combined his engineering expertise and obsession with cars to step into automotive journalism.

When he’s not writing about cars, Braden can be found wrenching on his extensive collection. Whether they’re built for style, drifting, going fast, or just enjoying time spent on the road, Braden relishes working on cars and, ultimately, “making something from them.” Braden is most inspired by the individualism people can display when modifying their vehicles.

To keep himself up to date with the industry, Braden follows a variety of automotive websites and checks in with them daily.