The Eunos Cosmo Was So Advanced It Was The Only Mazda Ever To Get A Triple-Rotor Engine: Holy Grails

Mazda is one of those automakers that is equal parts fascinating and bewildering. This is a brand still dedicated to the Wankel engine even though everyone else has given up on it. Meanwhile, it developed an all-new straight six in an era where many other automakers are downsizing to turbo fours or going electric. Back in the 1990s, Mazda was a technology trailblazer when it launched the Eunos Cosmo. The last of the famed Cosmo line, it was the world’s first mass-production vehicle with a three-rotor Wankel and a twin-turbo, the most powerful car in Japan, the first car with a built-in GPS navigation system, and more. Just 8,875 of these Cosmo were sold and only in Japan, making them a rare sight anywhere.

If you’re not a Mazda fan, you’re probably wondering what the “Eunos” is in the Cosmo’s name. This story takes us back to Japan’s famous “bubble economy” period when stocks and real estate values soared and it seemed as if money rained down from the sky in Tokyo. The nation’s auto and moto manufacturers went nuts in the bubble economy, advancing technology and power at impressive rates. Many of today’s famed classic Japanese cars and motorcycles from Honda’s CX500 Turbo to the Mazda RX-7 FD were bubble-era darlings.

Until the end of the 1980s, Mazda marketed its cars through its own brand as well as through Ford. At the end of the decade, Mazda decided to capitalize on the bubble era by diversifying its sales channels. It launched Autozam, a lower marque covering inexpensive Kei cars. Some Autozams were really just rebadged Suzukis and Autozam also got involved with importing Lancias, too. Upmarket from Mazda was Eunos, which provided the Japanese buyer with an upscale and sporty driving experience. Higher than Eunos was ɛ̃fini (Anfini), which was positioned to be Mazda’s exclusive luxury brand that ignored government tax regulations on engine displacement and vehicle dimensions. There was also Amati, which was supposed to be Mazda’s U.S. luxury brand version of Acura or Lexus, but that didn’t work out.

As Mazda notes, having those five different sales channels in 1989 brought on a challenge. Those channels needed their own cars and they also needed to be unique. Mazda’s solution was to just crank out tons of models:

In the following five years, Mazda launched more than 25 new models. Not only did the carmaker quickly ramp up its offerings, it also engaged in product differentiation. To develop new models to suit the characteristics of different distribution channels, special consideration was given to creating positive distinctions between vehicles, with an emphasis on their individuality. Buoyed by the economic boom and their ambitions for further business growth, Mazda’s engineers worked hard to incorporate novel and innovative designs and technologies into the new models. It truly was an animated period.

It’s hard to say what was the best car to come out of Mazda’s brand blitz. The original MX-5 Miata is an automotive icon and rotary fans will pay tens of thousands of dollars for a good RX-7. Don’t forget, Mazda also made the fantastic 323, and even the MX-3 with its novel baby V6 engine. Mazda was still producing the Parkway rotary bus during this time, too!

Mazda has been the subject of a few Holy Grail entries and for good reason. This is a company that knows how to have fun and knows how to build cars that enthusiasts lust after. The Eunos Cosmo is another one of those legends. And the good news is you can import one today.

The Future, Yesterday

To understand what makes the Cosmo so great, let’s take a trip even further back into the past.

In 1955, Japan’s Ministry of International Trade and Industry (MITI) was on a mission to get the nation’s people on wheels. It started with the concept of a people’s car. Then, MITI realized that Japan’s post-World War II industries weren’t competitive on the global stage. MITI developed a plan to put Japan’s industries, especially the automotive industry, on the same level as the titans from America and Europe. In an effort to achieve this, MITI sought to condense Japan’s automotive industry. The logic was that fewer but larger automotive firms would be more competitive as opposed to a bunch of small companies trying to make it. Thus, smaller firms, including Toyo Kogyo, Mazda’s former name, were under the threat of being merged. Only the companies that offered something exceptional would be more likely to remain independent.

Toyo Kogyo developed a brilliant plan to make itself stand out by doing something the other Japanese automakers weren’t. Tsuneji Matsuda, then Mazda’s president, decided that the way Mazda would prevent itself from a forced merger would be by developing and selling a different kind of engine than its competition.

In 1961, the year MITI launched its initiative, Mazda sent engineers to NSU, the German firm that had been experimenting with Felix Wankel’s rotaries since the 1950s. Even though the Wankel had been patented for over 30 years, Mazda discovered that the Germans still hadn’t solved a critical issue, from Mazda:

The Wankel rotary engine is characterized by the unique triangular shape of its rotor. As the rotor turns at high speed, the apex seal, which is attached to each apex of the triangle to ensure air tightness, undergoes friction with the inside surface of the cocoon-shaped rotor housing. This process causes abnormal wear on the chrome plating finish within hours, leaving traces called “chatter marks,” which are also known as the Devil’s nail marks. Finding a way to avoid such damage was critical to the development of a practical rotary engine.

Why was this a big deal? According to Mazda, the prototype rotary engines received from Germany failed quickly.

Determined to solve the chatter mark issue, Mazda formed the “47 Samurai,” an engineering team led by Kenichi Yamamoto. Those engineers threw everything on the table, including making apex seals out of horse bones and cow bones. These engineers were dedicated to rotary development, spending so many of their waking moments trying to solve an issue that even Mazda began to think was impossible. Indeed, as development continued with the chatter mark issue unsolved, the automaker began to see the rotary as a waste of resources.

But the engineers were undeterred and by 1963, they delivered a breakthrough, from Mazda:

At long last, the team achieved a breakthrough in 1963, when an engineer proposed the idea of changing the apex seal’s frequency characteristics by modifying its shape. A cross-hollow seal with a cross-shaped hole near the apex of the seal was developed and tested. The test proved successful, with no chatter marks appearing on the inside surface of the engine. In the following year, with the support of Nippon Carbon Co., Ltd., Mazda created a new apex seal made from aluminum-carbon composite materials. This innovation opened the way for bringing rotary engine-powered cars to the street.

Now that the engineers figured out how to make rotaries last longer, Mazda needed a sleek vehicle to showcase its innovation. In 1964, Mazda announced the Cosmo Sport, which would be sold outside of Japan as the 110S. Testing began after, which included subjecting the improved rotary engine to 700,000 kilometers of high-speed endurance testing.

The Cosmo wasn’t just a body to house a new technology, but a wonder all on its own. Mazda’s designers gave the vehicle a futuristic body with long, flowing lines. It was a car that looked like all it needed was a set of wings to fly. The Cosmo was also thoroughly modern with front disc brakes, a DeDion rear axle, and a curb weight of just 2,050 pounds thanks in part to that Wankel.

The engine was also a promising unit. Rotary engines have fewer parts than piston engines, a more compact size, and operational smoothness. How smooth? The rotary engine in my Suzuki RE-5 is so smooth that if you plugged your ears, you might believe you were riding an electric bike. Rotaries also like to rev pretty high. When Mazda’s engineers finally cracked the code to the chatter mark issue, there were side benefits in that Mazda’s rotaries also consumed less oil and made greater torque. In theory, this is a great engine for a low-slung sports car.

The Mazda Cosmo Sport launched in 1967 with a 982cc two-rotor engine rated at 110 HP and a top speed of 115 mph. Later, power would get bumped to 128 HP with a top speed of over 120 mph. Mazda says it made about one Cosmo Sport a day and sold around 30 a month. When production ended in 1972, Mazda built 1,176 units, all by hand. That isn’t a lot of cars, but it cemented Mazda’s love for the rotary.

The Cosmo became a model line in 1975. The 1975 Cosmo AP, which won the Car of the Year award by Motor Fan Magazine in 1976, would be offered with both piston engines and rotary engines. The first-generation Cosmo is notable for its American-inspired design and personal luxury car flair. You were even able to buy your first-gen Cosmo with an opera window and a leather landau roof! Sales were also good, as Mazda sold 20,000 units in just six months.

Mazda rolled a second-generation Cosmo out in 1981. The Cosmo remained a personal luxury car, but now Mazda gave the vehicle greater attention to aerodynamics. Pop-up headlights were in, as was a design slippery enough for a coefficient of drag of just 0.32, which was a big deal over 40 years ago. Once again, the vehicle was available with both piston engines and rotary engines, but new was the addition of a diesel piston engine as well as a sedan body style.

One of the selling points of getting a second-generation Cosmo with a rotary engine was the fact that since every rotary engine was under 1.5-liters, there were significant tax savings to be had. A Mazda Cosmo fitted with a 12A Turbo rotary was also the fastest car in Japan until the Nissan R30 Skyline RS came around.

All of these cars are awesome, but none of them are the holy grail of Mazda luxury rotaries. For that, we have to look to 1990.

The Grail

Announced in 1989, the Eunos Cosmo would be the last car to wear the beloved name. And Mazda made sure the Cosmo went out with a bang. As the automaker says in its own retrospective, the Eunos Cosmo was intended to be “the greatest rotary-engine car in history.” It was also supposed to be Mazda’s flagship rotary car and the headlining vehicle of the then-new Eunos brand.

How would Mazda achieve this? Well, the new Cosmo had to beat every generation before it while also capping off a run that started with the innovative Cosmo Sport. Mazda would beat its own great work by upping the technology and making its first and only production three-rotor Wankel. Unlike Honda and Toyota, which made its Acura and Lexus flagship luxury cars sedans, the Eunos Cosmo would go back to being just a coupe, but a lavish grand tourer sitting at the bleeding edge of what Mazda engineers could achieve in the late 1980s.

Mazda started building the final Cosmo by giving the vehicle its own platform. Dubbed the JC platform, it wasn’t used on any other Mazda vehicle and it had some interesting quirks. The Eunos Cosmo would ride on a control arm front and multilink rear suspension. For a departure from the norm, the Eunos Cosmo had two extra rear shocks, both mounted in front of the rear coilovers, to improve ride quality. The platform was further supported by variable power steering and vented disc brakes.

Slathered on top of the JC platform was a futuristic, yet subdued body. Mazda cleaned up the sheet metal by hiding the vehicle’s radio antenna in the rear window and the GPS antenna in the roof. This was an early application of hidden antennae, yet, Mazda said the GPS was accurate to within 50 yards. While the Eunos Cosmo certainly has a design that dates back to the early 1990s, it still looks more stately than many of today’s cars.

Really, the magic of the vehicle happened under the hood and in the interior. Let’s start with the interior, where Mazda spared no expense in creating a space comparable to a European luxury car. From Mazda:

Only the best materials were adopted in order to create an interior space that would feel comfortable and luxurious to both the driver and passengers. These included, for example, top-quality Austrian leather for the seats as well as wood trim harvested from elm trees in France and polished by Italian craftsmen in Milan for the interior wood panels. In addition, the Eunos Cosmo was equipped with the world’s first GPS navigation system and other cutting-edge electronics, making it an unprecedentedly premium personal coupe.

Mazda’s really burying the lede on the technology there. The vehicle’s interior resembled a lounge and had a futuristic wraparound dashboard. In those dark spaces sat a set of analog and color LCD gauges. On a center stack sat a CRT screen called the Car Control System, which controlled GPS navigation, climate control, and entertainment.

In terms of luxury, the Eunos Cosmo came loaded. Standard features included automatic climate control, automatic driver power window, power locks, power mirrors, power-folding mirrors, and power seats. The steering wheel also automatically moved itself out of the way for easier ingress and egress.

The car also featured cruise control, a cassette deck, a CD player, a six-speaker surround sound system, and steering wheel controls. Options included a 12-disc CD changer, an upgrade from cloth to leather seating, the Car Control System computer, and, of course, engines. If you didn’t get your car with the CCS, you got a button bank to handle those actions.

The standard Eunos Cosmo engine was a 13B-REW 1.3-liter twin-turbo two-rotor Wankel. It was rated for a healthy 230 HP and 217 lb-ft of torque. Most Eunos Cosmo are believed to have this engine. About 40 percent are believed to have the 20B-REW 2.0-liter twin-turbo three-rotor Wankel. A small turbo spools up quickly for lower RPM runs while the bigger turbo kicks in for high RPM fun.

This was the first and only time Mazda supplied a production car with a three-rotor engine. Both engines have a sequential twin-turbo system, which helps eliminate turbo lag. So far as I can tell, this is the only production car in history with a triple-rotor setup.

Going for the 20B officially netted you 280 HP and 297 lb-ft of torque. However, those were the numbers generated from the infamous “gentleman’s agreement.” In reality, these engines are estimated to put out around 300 HP, maybe a little more. To put that into perspective, a 1989 BMW 850i made 295 HP from its 5.0-liter V12. So, this rotary-powered Japanese grand tourer was competing with V12 legends.

Sadly, all Eunos Cosmo examples, regardless of engine, came fitted with a four-speed automatic transmission. This transmission did have a sport mode and a manual mode but limited the engine to a redline of 7,000 RPM because the transmission reportedly couldn’t spin faster. But that does make sense since the Eunos Cosmo was supposed to be a fun high-end luxury car. Consider that this was a 3,550-pound car, but it still hit 60 mph in around 6.5 seconds. That won’t blow your socks off but can be a load of fun.

Mazda made a lot of claims with the Eunos Cosmo. The automaker claims the Eunos Cosmo was the first production car with a three-rotor engine, the first mass-produced car with a sequential twin-turbo setup, the first car with a built-in GPS, the first car with an automatic transmission sport mode, and the first Japanese car to use a “Palmnet” serial data communication system for easier diagnostics. To be clear, Mazda wasn’t the first to market with a lot of these technologies. The Maserati Biturbo had two turbos in the early 1980s, but those were parallel turbos. The Porsche 959 also beat Mazda to sequential turbos, but that car wasn’t a mass-production model.

As you could expect, the price for all of this power and luxury wasn’t cheap. A base Cosmo 13B Type-S with cloth seats and without the snazzy CCS computer was ¥3.3 million, or roughly $27,200 in 1990 money. A 20B Type-E with every option checked ran you about ¥5.3 million, or about $43,650 in 1990 money. Toss those figures into a Japanese inflation calculator and the result today would be ¥3.9 million and ¥6.3 million, respectively. However, exchange rates are a funny thing and currently, ¥3.9 million is about $26,636 while ¥6.3 million is worth about $43,028.

If we tied those 1990 prices to the inflation of the U.S. dollar, the base model would be the equivalent of $65,490 today while the top spec Cosmo would be $105,097.

That put the Cosmo in a weird place as the most expensive car Mazda ever sold by that point. A high option CX-90 today is more expensive, but that model is not sold in Japan. The Cosmo was more expensive than the V8-powered $37,500 Lexus SC 400, but only slightly cheaper than a V12-powered $46,700 Jaguar XJS. The rotary Mazda was significantly cheaper than the $77,700 BMW 850i and made similar power to boot.

Reportedly, the press raved about the Eunos Cosmo, comparing it favorably to V12 fare from the era. While I could not find a period review, here’s what our old friends Patrick George and Raphael Orlove had to say about the Eunos Cosmo in a modern review:

It’s a gigantic coupe that rides smoother than anything short of a Rolls-Royce, quieter than anything short of a Tesla, and with an engine so bold that no other car maker has ever attempted to produce one since.

This is a triple-rotor engine, the only one ever put into production. It was a 2.0-liter twin-turbo unit supposedly good for about 300 horsepower. Mazda’s rotaries are known for being big on horsepower, small on low-end torque. Not this one. It pulls on the highway with more shove than you’d expect. It does not feel slower than a Supra of its day, though like several cars we drove from this era, it is hampered somewhat by its now-archaic four-speed automatic transmission.

I wanted to change my whole life for this car. I wanted to start dressing better, being better to those around me every time I laid into the throttle, revs climbing up that wraparound dash. It’s not just that it was a good car, this is a better car than all of the cars it competed with, and it’s still nicer than most new cars today, with tech and refinement to match them. That it came from a company as small as Mazda is absolutely unreal.

American journalists begged for Mazda to bring the car to America and that was supposedly part of the plan for Amati, but the brand failed to launch. And the Cosmo? It never left Japan, and even in its home market, the Eunos Cosmo wasn’t a strong seller. If the high price wasn’t enough to turn buyers away, maybe the crash of the bubble era stopped them from buying a luxury car. Just 8,875 Eunos Cosmos were built between 1990 and 1995, and who knows how many survive to this day.

If you want one, you’ll almost certainly have to turn to Japan’s wonderful used car sales systems. Based on the sales data I have on hand, one Eunos Cosmo SX sold at auction for $11,000. If you do not want to deal with the auctions, I found three Eunos Cosmo for sale on Goonet for between $16,438 and $23,401. It should be noted that all of the cars I found listings for were of the 13B variety. You could expect to pay even more for a 20B Cosmo.

Did Mazda achieve its goal of making the world’s best rotary car? Maybe, but few people bought it. If you do find one of these wonderful cars, you’ll be getting a weird exclusive car from a wild time in Japan’s history. No other automaker has come close to making a car like this. Mazda didn’t even try repeating the Cosmo. And as the world moves away from internal combustion, it’s unlikely another automaker will try to make a Cosmo.

Do you know of or own a car, bus, motorcycle, or something else worthy of being called a ‘holy grail’? Send me an email at mercedes@theautopian.com or drop it down in the comments!

(Images: Mazda, unless otherwise noted.)