The forgotten triple-wankel: The Eunos Cosmo

The fourth generation of Mazda’s forgotten rotary-powered halo car.

Few cars have boasted the heart of a wankel. An experimental triple-rotor setup that ended in failure, was this forgotten rotary powered luxury GT actually one of Mazda’s best?

Mazda Cosmo 110S (1967)

Originally birthed as a twin-rotor wankel powered sports car in 1967, the launch of the Cosmo line was intended to give Mazda a luxury image, acting as a ‘halo’ car – much like the R8 for Audi, or the GT-R for Nissan. A flagship luxury sports car with a technological nameplate and deservingly so; powered by a pioneering first-of-its-kind twin-rotor wankel engine. The 982cc ’10A’ motor produced an output of 82kW, resulting in a claimed 0-100km/h figure of 8.7 seconds, quite decent for its time. In 1968, the release of the Series II increased the same 982cc twin-rotor’s output to 95kW, bringing that figure down to 8.1 seconds. The Cosmo would live for three more generations, up until 1996 – but you’ll hear more about that later.

Eunos Cosmo (1990)

Fast forward to 1990.

The fourth iteration of the Mazda halo car, the new Eunos Cosmo. A four seater – two door coupe, powered by a one-of-its-kind triple-rotor wankel engine. A pioneer in technology with a name based on space exploration, this was Japan’s answer to the BMW 850CSi and Aston Martin DB7. The new Cosmo adopted a newly developed sequential twin-turbocharger setup, where a primary turbocharger stays active for lower engine RPM operation and a secondary turbocharger activates with faster engine operation; a technology first used in Porsche’s famed 959 a few years earlier. Brakes came in the form of ventilated disks on all four wheels, and an 85 litre fuel tank was fitted. This may sound like a lot, but with the average fuel economy of a bus (many owners averaging around 27L per 100km), that 85L suddenly sounds like it could do with a bit more…

’20B-REW’ Twin Turbo Triple-Wankel

Under the bonnet housed a monstrous 1962cc twin-turbocharged ’20B-REW’ triple-rotor, producing no short of 224kW of power and 403Nm of torque, fed with sequential twin-turbochargers running a decent 10psi of boost. Holding the record at the time the largest wankel engine ever fitted to a Mazda production car; this also crowned the 2 litre triple-wankel upon release as the most powerful Japanese production engine ever made.

Mated to a newly-developed 4-speed automatic and fed to the rear wheels, 0-100km/h could be achieved in an incredible 6.2 seconds, although no official 0-100km/h time was ever released. Speed limited to 200km/h – once lifted, the triple-rotor could spin the Cosmo up to speeds of over 250km/h.

A familiar 1308cc ’13B-RE’ twin-rotor was also offered, producing 169kW and 294Nm. Being the base engine, it could accelerate from 0-100km/h in around 7.4 seconds, and onto a governed top speed of 180km/h. It proved to be a much less popular choice.

Eunos Cosmo Interior (1990)

Following the luxury theme, and continuing the naming system akin to space exploration and forward-thinking, the fourth ‘JC’ generation Eunos Cosmo featured an interior which housed one of the best examples of a ‘retro vision of the future’ you’d ever find in a car. The technology was best described as – astounding.

A prime example of technology was the optional Mitsubishi-developed CRT colour touch-screen, used to control the radio, CD player, tape player, climate control, mobile phone controls, NTSC TV, as well as a first-of-its-kind in-car GPS satellite navigation with traffic information. All controllable via steering wheel buttons. Wow.

The first ever car that implemented a system called ‘PALMNET’ (which would later be standard to many Japanese manufacturers), it provided smart serial data communications, meaning the computer systems would communicate with each other much more effectively, namely the engine and gearbox computers.

Japanese manufacturing was no longer analogue. It was time for Mazda to switch to the digital age.

Eunos Cosmo Rear (1990)

Ending official production in 1996, the reception of the Eunos Cosmo was not as well as Mazda had hoped.

The car was great. Better than great. Better than many cars on the roads today..

What made it a failure?

Eunos Cosmo (1990)

1. Vehicle dimension regulations

The increase in size of the new Cosmo meant that it no longer met Japanese vehicle dimension regulations, meaning that buyers of the Cosmo were met with road taxes as opposed to no tax with smaller vehicles.

2. The 1992 Mazda RX-7

In 1992, Mazda brought out a much more popular car, stealing sales from their own Cosmo. The RX-7 proved to be a much more affordable bang-for-your-buck sports car, and also proved to be much more popular. We won’t go into detail about the RX-7, but you would have to be hiding under a rock to not have heard of the famed RX-7.

3. Japan’s ‘Lost Decade’ financial crisis

Since 1986, Japan had been trapped in an asset price bubble which greatly inflated real estate and stock market values, and a rapid increase in economic activity made demands much higher than suppliers could produce, driving asset prices up to incredibly high values. Early 1992, just 2 years into the Eunos Cosmo’s production – the bubble burst. Japan’s economy rapidly declined, and would continue declining for over a decade. People stopped spending, and prices of assets plunged, leading to what many people call ‘The Lost Decade’.

4. The price

The Eunos Cosmo at the time was the most expensive car Mazda ever produced, and still to this day, no Mazda production car has ever exceeded it’s brand new price – and after the asset crash, this instantly made the Cosmo a car that was out of most people’s price territory.


The most expensive car made by Mazda; a Japanese domestic market only car (with the exception with a few sales in Australia) – stuck in the heart of a Japanese economic recession and overshadowed by the upcoming RX-7 – the new Cosmo did not sell as well as Mazda had expected, selling just 8,875 units, and after just four generations, with the fourth lasting just six years in production, Mazda’s space-race vision of the future nameplate was left behind on the bookshelf to collect dust.

We can however say with our upmost belief – The Eunos Cosmo was; and still is one of Mazda’s finest creations.

AutoNews Australia

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