Mazda Eunos Cosmo

Mazda Eunos Cosmo (JC, 1990 to 1995): the three-rotor unicorn

One engine makes this whole car famous

The Eunos Cosmo was Mazda's flagship luxury GT coupe, sold through the upmarket Eunos channel from 1990 to 1995 and never offered outside Japan. It was never meant to be a sports car. Think of it as a big, quiet grand tourer that happens to hide one of the maddest engines ever bolted into a road car.

That engine is the whole story. The top version runs the 20B-REW, a 2.0 litre triple-rotor with sequential twin turbos, and as far as anyone can tell it is the only mass-production three-rotor car the world has seen. Officially it makes about 280 PS, which is just the Japanese gentlemen's-agreement cap that every fast car of the era quoted, and most people reckon the real figure sits a fair bit higher. Torque is somewhere around 400 Nm. There was also a twin-rotor 13B-REW car, and by most accounts that was the bigger seller, so the three-rotor is the rarer beast of the two.

It was a proper technology flagship too. Options included the CCS, or Car Communication System, a colour touchscreen that ran the climate and the stereo. It also carried one of the first built-in GPS satellite navigation setups fitted to any production car. In 1990 that was space-age stuff, and it still turns heads at a car meet today.

On the road it is quick and smooth, and it is thirsty in a way that makes headlines. This is a heavy luxury cruiser rather than a corner-carver, and it drinks fuel and oil the way rotaries do, only more so with three rotors and two turbos to feed. Values have been climbing for a while now, because there is nothing else quite like it and there never will be.

Now the buyer notes. The first job on any Cosmo is a compression test on a proper rotary tester, done warm, because the 20B is expensive and specialist to rebuild and the parts are scarce. Apex seals are the thing that kills these engines, so weak or uneven compression is a walk-away. Budget for the fuel and oil habit before you fall in love. The sequential-turbo plumbing and the vacuum lines are old and fiddly, and a car that has never had them sorted can run rough for reasons that take days to chase down. The CCS screen and its electronics get tired with age, so treat a fully working one as a bonus rather than a given. And check for rust properly, underneath as well as on show. My honest advice is to buy the best example you can find and pay what it costs, because a cheap broken 20B is a bottomless pit.