Six Non-Mazda Cars Fitted With Rotary Engines

If there’s one thing forever associated with the Wankel rotary engine, it’s Mazda. Powering production vehicles from the Cosmo’s launch in May 1967 to the last RX-8 leaving the plant in June 2012, the Mazda rotary practically defined the company’s image in enthusiast circles. But while Mazda undoubtedly popularized and refined the rotary, they were by no means its sole manufacturer. In fact, no fewer than nine different manufacturers fitted a Wankel engine in at least one factory car (not including Wankel motorcycles): Mazda, Škoda, NSU, Citroën, AvtoVAZ, Mercedes-Benz, Audi, AMC, and Chevrolet. Granted, some of these vehicles were just basic toolroom prototypes or conceptualizations (some with more development time than others). But a surprising amount of production models also slipped through the cracks, sporting Wankel engines with varying levels of success.

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Considering the Wankel is best-known as a “burn twice as bright” engine, trading reliability and fuel efficiency for its simplicity and outstanding power/weight ratio, it’s no wonder that most automakers phased out this engine, Mazda included. Sadly, the only remaining rotary in a vehicle other than a concept car doesn’t even power its wheels, being the one-rotor range extender in the Mazda MX-30. 

These engines certainly have the potential to be quite reliable, though they were ultimately doomed by factors like development costs and tightening emissions controls. Mazda were essentially the only company willing to go the extra mile for the rotary, thanks largely to its 1961 license agreement with NSU to continuously develop the engine. Still, that didn’t stop manufacturers other than Mazda from experimenting throughout the mid-late 20th century, using the various advantages of the rotary to the fullest. Let’s take a look at a few more noteworthy (and bizarre) examples.

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While not the first rotary-powered vehicle ever, the 1964 NSU Spider was certainly the first production rotary to hit the road with any sort of respectable number. Designed by Bertone, this handsome little roadster sports a rear-mounted single-rotor producing 50 horsepower. That doesn’t sound like much, so to put it into perspective, this engine displaced just 497cc. Conversely, a 1964 Volkswagen Beetle produced just 40 horsepower from its, 1,192cc engine. Thanks in-part to this tiny engine, this meant that the NSU Spider tipped the scales, rather alarmingly, at just 700 kilograms, or about 1,500 pounds. The engine itself only weighed a spritely 125 kilograms, so this thing was a proper go-kart despite the rather pedestrian-sounding power figure. Just 2,375 NSU Spiders were built from 1964-1967, also making the Spider among some of the rarest production cars of the era.

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The NSU Spider’s journey coincided with Mazda’s original license agreement with NSU to develop the rotary. As such, the Spider became something of a design study for Mazda engineers, working for years to refine the unique engine configuration for their upcoming Cosmo. It was a development process fraught with problems, with the biggest issue being the engineering behind the apex seal – the component responsible for separating the different chambers within the Wankel engine. 

The science behind developing the “perfect” apex seal is still ongoing, though at the time it was far less-understood. As such, its lack of refinement, unreliability, and the handmade body (and high price tag) served as a prelude to the fall of NSU as a company. It was an absolutely gorgeous and pioneering little car, just not something conducive to large-scale production.

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This next entry, also by NSU, marks the first rotary-powered car with strong production numbers (over 37,000) and a lifespan of more than a decade. Originally marketed as a luxury car, the NSU Ro 80 made waves within the automotive community as an innovative and modern design, though its success couldn’t stave off the company’s financial issues and subsequent merging with Audi. Despite this, the Ro 80 boasted a wealth of information regarding the further development of the rotary engine. At the time, the Wankel was still a relatively unknown specialist powerplant, and because this was its first proper introduction to the mass market, NSU provided extensive design studies detailing the engine’s anatomy. Ultimately, the NSU Ro 80 left a lasting legacy on multiple fronts, including becoming the first ever West German-built car voted Car of the Year in 1968.

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The Ro 80s main contemporary selling point was its refinement. The body, designed in a wind tunnel, provided excellent aerodynamic efficiency and was praised for its modern styling. The powertrain and running gear were equally contemporary, now up to 130 horsepower from a two-rotor configuration, and sat on fully-independent suspension. This drastically improved the Ro 80s marketability, helping NSU and subsequently Audi shift tens of thousands until production ended in 1977. 

Along with its contemporary, the Mazda Luce, the Ro 80 set an early precedent for the rotary engine’s usage in vehicles other than specialist sports cars and toolroom prototypes. However, persistent reliability problems ultimately doomed the Ro 80s reputation once owners started putting miles on the platform, leaving it with the reputation of one of automotive history’s most noteworthy failures.

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Let’s be honest — a Pacer is, by many accounts, already quite a weird car to begin with. Even at the time, it was a bit of an odd duckling, with contemporary reviews praising the car’s utility but criticizing its extremely distinctive “fishbowl” styling. But there’s a reason why AMC designed the Pacer this way: it was originally intended as a compact car fitted around a rotary engine.

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First dubbed “Project Amigo” under AMC’s development, the Pacer was designed during the height of the Wankel’s newfound notoriety. The engine’s main selling points greatly appealed to compact car designs, with its inherent light weight and small footprint providing ample power in a tiny engine bay. This greatly influenced the Pacer’s design architecture, with AMC set to purchase GM’s RC2-206, their 206 cubic-inch two-rotor powerplant, for use in the Pacer. GM also wanted to use this engine in its own compacts, such as the Chevrolet Vega, with magazines like Popular Science referring to it as “the beginning of the end for the piston engine” and praising its (theoretical) reliability. Ultimately, though, development stalled out in favor of conventional designs, largely due to tightening emissions regulations.

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The GM rotary program’s demise in 1974 ultimately meant that, naturally, all related projects died with it, including the rotary-powered Pacer. Ultimately most of GM’s rotary project details faded to obscurity, with little apart from the occasional magazine article left to show for it today. As for the Pacer, AMC redesigned it for their more typical powerplants like their straight-six and V8. That said, AMC built a few test mules with several different rotary engines sourced from other manufacturers, but these remained more proof-of-concepts than viable production vehicles.

Speaking of GM, the most noteworthy vehicles to come out of the GM Rotary Combustion Engine (GMRCE) program were unquestionably their prototype rotary Corvettes. Developed specially as a showcase car for the new engine technology, the first of these projects was known internally as XP-897 GT. GM built this vehicle on a modified Porsche 914/6 chassis fitted with the prototype RC2-206 engine, rated for 180 horsepower. 

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The body, penned by Bill Mitchell’s design team and fitted by Pininfarina, showcased the engine beneath a prominent rear window, its striking features capturing the attention of press viewers ever since. The original project called for a compact muscle car, with GM cutting 6.5 inches off the Porsche chassis to accommodate the body, playing once again into the rotary’s strength of being a very tightly-packed engine configuration. Ultimately, like the rotary Pacer, the XP-897 GT failed along with GMRCE, but not before the project also produced the absolutely mad-sounding four-rotor Corvette.

This car, based on GM’s XP-882, essentially just mated two RC2-206 powerplants together on a common shaft, creating a 585 cubic-inch four-rotor capable of 350-plus horsepower. Simply known as the “Four-Rotor Car,” GM developed this monstrosity right as the Oil Crisis impacted the world, with the original intent being a precursor to a new Corvette. As such, GM finished the interior to a level befitting of a proper late-stage concept car and marketed their GMRCE project via showcases, newspaper ads, and brochures. 

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However, as mentioned before, the Oil Crisis directly led to the severe tightening of global emissions standards, which effectively doomed GM’s rotary program. In the end, emerging rotary technology was simply not as viable as implementing restrictions on the well-understood piston engine during such a critical and delicate time period in automotive history.

The ubiquitous French manufacturer actually built two rotary-powered vehicles, the first being the experimental M35. Unlike previous cars in this list, this humble sedan was never actually intended for mass production, with Citroën originally committing to 500 units before ultimately building 267. As such, we’ll focus on the follow-up, a vehicle very much built en masse: the GS Birotor.

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As the name implies, the Citroën GS Birotor is a GS re-engineered to house a two-rotor Wankel powerplant. Originally introduced at the 1973 Frankfurt Auto Show, the GS Birotor was much more than just an engine transplant — in reality, the French company altered a significant number of components. These improvements include features such as five-lug wheels, four-wheel disc brakes, flared fenders, and an upscale interior. As such, the Birotor is far more of a comprehensive overhaul, similar to something like the early Pontiac GTO being a special package for the LeMans.

The reasoning behind this decision lay in the inherent design characteristics of the rotary, being a very smooth engine with low torque curve in addition to its other qualities. During the mid-20th century, Citroën significantly impacted the automotive world with its innovative solutions in practicality, ride quality, luxury, and quirky features. Taken in this context, a rotary powerplant offers Citroën an easy solution to retain the car’s characteristic aerodynamic shape while also improving power and general refinement. Unfortunately, much like many other rotary-powered machines, the GS Birotor failed to find traction in the masses, ending production with just 847 built.

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Now, this is a properly gorgeous sports car. Developed during the late-1960s as an experimental platform for radical engine and aerodynamics designs, the C111 debuted at the Frankfurt Auto Show in 1969 as a radically-styled prototype fitted with a three-rotor Wankel engine. However, it took less than a year before the team decided to tack on a fourth rotor, increasing power output from 276 to 345 horsepower. Mercedes assembled 12 examples, each with its own bespoke test platform, never intended for sale. They fitted all but one of these with Wankels, the final being a V8 turbo-diesel.

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Such an exercise might be considered as unprofitable, if not a reckless business decision — after all, people were practically lining up to pay good money for this machine (and understandably so). But test mules were quite common in those days, with GM serving as a prominent US example (such as their CERV models). After all, these were the days in which such innovative, sleek design architectures and engine configurations were still incredibly groundbreaking, especially for a West German company riding off the reputation loss suffered by NSU rotaries.

Be that as it may, Mercedes still designed the C111 as a proper driver’s car, fitted with a full dashboard and all the usual appointments. Further, the sculpted body features massive side-mounted intake vents to feed and cool the engine in everyday use, a necessity for long-distance driving studies. The car also wore its 300SL influence on its sleeve, with the characteristic Gullwing doors an easy giveaway. Ultimately, despite the public begging Mercedes for a serial-production model, the company shelved the idea, instead continuing development well into the mid-late 1970s as purely a study car, going through several design and powertrain iterations (and breaking records in the process).

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