RX-Rated: Mazda’s Early Rotary Cars, Part 1

1971 Mazda R100 coupe front 3q
The Familia Rotary/R100 originally came with the 982 cc (60 cu. in.) 10A engine, which in U.S. trim was rated at 100 hp (75 kW) and 92 lb-ft (125 N-m) of torque. Substituting the larger 12A and 13B engines from later Mazda rotary vehicles is a straightforward swap, providing more power with only a very modest weight penalty; this car is now powered by a later 13B (1,308 cc/80 cu. in.) engine. (author photo)

Export sales, racing success, and the addition of the sedan brought about a healthy increase in total Familia Rotary/R100 production, which climbed from around 28,000 in 1969 to a peak of 31,328 in 1970, representing around 14% of Toyo Kogyo’s total passenger car production that year. The rotary Familia received a number of minor updates late that year, but it was now overshadowed by newer models, and sales for 1971 and 1972 dropped off substantially. The Familia rotaries were withdrawn from Australia in late 1971 and from the U.S. after the 1972 model year, and from the home market in 1973; the redesigned Familiar that bowed that October was not offered with a rotary engine. Total production of the rotary Familias was 95,891 units.

ROTARY RARITY: THE LUCE R130

Alongside the RX-85 at the 1967 Tokyo Auto Show was another prototype, the RX-87, a hardtop coupe loosely based on the Bertone-styled Mazda Luce 1500, which had debuted in August 1966. The RX-87 was decidedly Italianate, looking rather like a cross between an Alfa Romeo Giulia coupe and a second-generation Chevrolet Corvair two-door hardtop.

Under the hood, the RX-87 traded the standard Luce’s 1,490 cc (91 cu. in.) SOHC four for a new 1,310 cc (80 cu. in.) 13A rotary engine. (The 13A was not related to the later Mazda 13B engine; it had different internal dimensions, where the 13B was a straightforward development of the 10A/12A series.) Unlike the Luce, which had a conventional front-engine/rear-wheel-drive configuration, the RX-87 mounted the compact 13A longitudinally ahead of the front wheels, driving a four-speed transaxle — it was Toyo Kogyo’s first front-wheel-drive car.

1970 Mazda Luce Rotary Coupe RX-87 badge copyright 2011 Murilee Martin per
The R130 was formally known as the Mazda Luce Rotary Coupé, but production cars, like the prototype, also wore “RX-87” badges on the rear fenders, just aft of the doors. (Photo © 2011 Murilee Martin; used with permission)

Christened Mazda Luce Rotary Coupé or R130, the production version of the RX-87 went on sale in October 1969. The R130 was the largest passenger car Toyo Kogyo had yet offered, significantly bigger than the Luce sedan on which it was nominally based. The Rotary Coupé’s 13A engine had less power than the smaller engine in the Cosmo Sport L10B, 126 PS (124 hp, 93 kW) at 6,000 rpm, but substantially more torque: 127 lb-ft (172 N-m) at 3,500 rpm.

Like the Cosmo Sport, the R130 had double wishbone front suspension (albeit with unusual rubber torsion springs rather than coils), front disc brakes, and a standard vacuum servo, but the Luce’s rear suspension was independent, with coil springs located by semi-trailing arms. In keeping with its price — ¥1,450,000 (a bit over $4,000) for the base Deluxe model, ¥1,750,000 (around $4,850) for the air-conditioned Super Deluxe — the R130 was well equipped and luxuriously trimmed, with a hefty dose of sound insulation. Toyo Kogyo marketed the R130 as a personal luxury coupe rather than a sports car, but it had brisk performance and a claimed top speed of 119 mph (190 km/h).

1970 Mazda Luce Rotary Coupe front 3q copyright 2010 Jens Kramer per
The 1969–1972 Mazda Luce Rotary Coupé was 180.5 inches (4,585 mm) long on a 101.6-inch (2,580mm) wheelbase with a curb weight of around 2,830 lb (1,285 kg) in Super Deluxe trim. Overall height was 54.5 inches (1,385 mm). The R130 was a true pillarless hardtop, with no B-pillars. (Photo © 2010 Jens Krämer; used with permission)

The R130 was offered only with right-hand drive and we don’t believe it was officially exported, although some eventually ended up in markets like Australia and South Africa. At home, the big coupe’s size, thirst, and high prices made it very rare. Only 976 were built before production ended in 1971. In October 1972, the R130’s place in the lineup was taken by a somewhat smaller, RWD coupe version of the second-generation Luce, sold in some markets as the RX-4.

Surprisingly, Toyo Kogyo never offered another rotary production car with front-wheel drive. The company’s next FWD model, the 1980 BD Familia (323 or GLC in other markets), was offered only with conventional four-cylinder engines.

ROTARY EXPANSION

By 1970, worldwide interest in the rotary engine had increased dramatically, with nearly every major automaker seriously considering rotary power. That November, General Motors signed a $50 million licensing agreement, joining a list of licensees that included not only Curtiss-Wright and Toyo Kogyo, but also Alfa Romeo; Daimler-Benz; Porsche; and the military vehicles arm of Rolls-Royce, which was developing an unusual rotary diesel for main battle tanks. The main attraction was no longer the rotary’s light weight, smoothness, or mechanical simplicity, but its exhaust emissions.

Photochemical smog had been a growing problem in major urban areas for years, particularly in areas like Los Angeles, which are prone to atmospheric inversion layers. In the early fifties, scientific studies had linked smog to unburned hydrocarbons (HC) and nitrogen oxide (NOx) emissions from factories and motor vehicles. The state of California established the first limits on automotive emissions in 1959, followed in 1963 by the state of New York. In 1964, the U.S. Congress gave the federal government authority to regulate air pollution at a national level. The trend was not limited to the United States. Large Japanese cities had smog problems as well and there had been debate in the Japanese National Diet throughout the decade about the possibility of automotive emissions standards.

In December 1970, the United States enacted the Clean Air Act (sometimes known as the Muskie Act, after Sen. Edmund Muskie, D-Maine), which defined stringent national limits for automotive carbon monoxide (CO), HC, and NOx emissions, slated to take effect in 1975. (California had already implemented its own standards for NOx emissions, which took effect in 1971.) In response, Japan’s Environmental Agency proposed comparable regulations for Japanese vehicles along with a phase-out of leaded gasoline.

1971 Mazda R100 coupe front
For 1971, Mazda’s fledgling U.S. operation switched to the new SAE net rating system, dropping the R100’s nominal output to 77 hp (57 kW) and 80 lb-ft (109 N-m) of torque. Like all North American Mazda rotaries, the R100 now had a thermal reactor to control hydrocarbon emissions. Federalized cars also received round headlights, as the rectangular units used in other markets were not legal in the U.S. (author photo)

In both countries, the new standards triggered a political firestorm. Many automakers insisted that meeting the proposed standards was technologically impossible, particularly the new NOx limits. CO and HC emissions could be controlled by improving combustion efficiency or with add-on equipment like air injection, but NOx was a more difficult proposition, in part because some measures that reduced HC and CO (such as running very lean mixtures) actually increased nitrogen oxide emissions.

It was in this area that the rotary engine showed new promise. As a side effect of its combustion chamber shape, high surface-to-volume ratio, and relative low thermal efficiency, the rotary had greater HC emissions than did a comparable piston engine, but those same factors contributed to much lower NOx levels. (Nitrogen oxide emissions depend in large part on combustion temperatures, which are generally lower in a rotary than in a comparable reciprocating engine.) In fact, the Mazda rotaries were among the very few engines manufactured in 1970 that could meet the 1975 NOx standards without modifications. The rotary’s hydrocarbon emissions, meanwhile, could be brought under control with the use of a thermal reactor, which injected air into the exhaust stream to complete the combustion process. Toyo Kogyo had already developed that technology, which was included on all U.S.-bound rotaries.

21 Comments

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  1. I’ve always loved Mazda’s rotary cars. Fantastic article, and I can’t wait for part 2…

  2. Great story looking forward to part 2. A friend in Tasmania had several of those bertone Luces nice cars the later models had the 1800 Capella engine.

  3. Thanks for the Mazda rotary article. I’m looking forward to reading Part 2. Despite growing up around Mazda rotary-powered cars, I learned quite a bit!

  4. It’s a real shame that no one can seem to lick the engine’s fuel and oil consumption problems. I have heard some discussion of Mazda using rotaries in hybrids, which makes some sense to me. Rotaries are so small and, on paper at least, elegantly designed.

    Man, that Luce coupe is a looker.

    1. I don’t know about hybrids, but Mazda has done quite a bit of development on a hydrogen-fueled rotary, which has been offered on a limited basis for fleet sales in some markets.

      If the next-generation 16X engine materializes, Mazda is hoping to reduce fuel consumption substantially, in part by adopting direct injection. Still, since piston engines keep improving in that regard, as well, I don’t know that the rotary will ever match the reciprocating engine in specific fuel consumption. Some things can be mitigated (like wall quench), but other factors, like the combustion chamber surface area to volume ratio, are sort of the nature of the beast.

      The Luce R130 is indeed a very nice-looking car. I’d never seen one before I started researching this story.

  5. Very interesting article, well, as usual, Aaron!
    The topic was somewhat forgotten in France after Citroën heavily invested in the technology, eventually failed to make it work and had to drop the project in the early 70’s. They had been so serious about it that the models developed in the late 60’s, the GS and the XM, were designed for a rotary. They had to hastily develop a reciprocating engine for the GS and make it fit in the engine bay that was not large enough.
    The XM eventually was painfully fitted with a Peugeot engine.
    Anyway Citroën was never able to design a good engine. This huge investment and its failure played an important role in the demise of the company.

    Nick

    1. “They had been so serious about it that the models developed in the late 60’s, the GS and the XM, were designed for a rotary.”
      You mean the SM, don’t you?

      1. I believe Nicolas was probably referring to the CX, which replaced the Citroën DS in 1974. I’ve never heard anything about the SM being intended for rotary power — of course the production cars had the Maserati V6 — but I think the CX was. The XM was the CX’s eventual successor, introduced in the late eighties.

  6. Right Aaron, my pen slipped, it was the CX.
    The XM was its successor.
    The SM, stangely enough, was fitted with the (in)famous Maserati V6 even though Citroën had such a faith in the future of the rotary as the ultimate replacement of the reciprocating.

    Nick

    1. Timing may have had something to do with it. Citroën didn’t build the first M35 single-rotor cars until the fall of 1969, and as I understand it, they were essentially evaluation models, not yet intended for large-scale production. The BiRotor wasn’t introduced until 1974, about four years after the SM debuted. Even if Citroën were keen to give the SM rotary power, it probably wouldn’t have been ready until a few years after launch, even in a best-case scenario.

      If things had worked out differently, I imagine Citroën might have added a rotary engine to the SM later, perhaps in a second-generation version for the mid-seventies. Of course, even if the Comotor engines had been more successful, the SM was not, and might have been dropped without ever getting a rotary engine.

  7. For them the rotary was the future type of engine for all applications, just as well as they were persuaded they had a market for the SM.
    With NSU, Mazda and others working on it it’s understandable.
    Your article is very interesting by showing how Mazda made a success of it, or at least could partly make a living with it, well… that’s a success, isn’t it?
    Strangely enough it didn’t catch on as an aviation engine either.
    Nick

  8. [quote=Administrator] Citroën didn’t build the first M35 single-rotor cars until the fall of 1969, and as I understand it, they were essentially evaluation models, not yet intended for large-scale production. The BiRotor wasn’t introduced until 1974, about four years after the SM debuted.[/quote]
    Starting in 69 a limited number M35, and in 73 GS Birotor, were sold to selected, faithful (and masochist) clients but the engine proved such a burden to maintain that Citroën offered to buy them back and scraped them. A few people only turned down the offer. The maintenance contracts were canceled for them. The few models still in existence are now very expensive collectors’ items, the day dream of all the GS enthusiasts.
    So there was actually a future for the rotary! ;-) As usual the car that nobody wanted became the car that nobody can afford.

    Nick

    1. The source I was looking at (John Hege’s [i]The Wankel Rotary Engine: A History[/i]) suggests that Citroën had basically intended to buy back the early evaluation engines from the outset, which would make a lot of sense.

      I don’t know about France, but in the U.S., automakers are legally obligated to provide parts support for production models for a specific period of time, typically 15 years — obviously not an appealing prospect for cars or engines that don’t end up in mass production! For that and other reasons, some automakers have tended to offer such evaluation vehicles only as a closed-end lease or other type of loan-out, with no option to actually purchase and keep the vehicle at the end; I assume that not actually selling it avoids triggering certain legal requirements.

  9. The Europeans have basically the same obligations as the Americans. As far as I understood, the deal was under specific conditions and since Citroën offered to buy them back it could cancel any support for those who rejecter the offer. It’s stupid it didn’t keep one example for history.

    Mazda is the only one who succeeded with a rotary over the years while all the others flopped.
    Well done!
    Nick

  10. This is an interesting article as usual, I’m waiting for the second part. While you’re at it, how about an article covering GM’s attempt to build a rotary engine?

    1. I thought about it, but in researching this article, I’m finding that detailed information about its development seems to be surprisingly scarce. While the development of the NSU, Mazda, and Curtiss-Wright engines is pretty well-documented, GM played it very close to the vest. To really do it justice would probably require talking to some of the engineers who worked on it, assuming that the people involved are still living, and willing (and able) to talk about the program.

  11. No need to mourn it’s passing. A technological dead end. I don’t miss the
    ffffttttt exhaust “note” of them at all.
    Used to be a few about Brisbane, Delighted to see and hear that rust and enlightenment of the owners has made them almost extinct.

    Good riddence. So it could rev to 5 digits.
    BFD.

  12. Wow, FANTASTIC article! Thanks for the great piece on Mazda, the detail and depths you go to are above and beyond. One of the best history-of-automaker stories that I’ve read. Thanks again!

  13. Another great article Aaron. Really appreciating your narrative drive and level of scholarship. I’m starting to believe the R100/1200 body was designed by Bertone as well, but can’t verify. Do you know of any text that addresses the connections between the Italian design houses and the Japanese manufacturers in depth?

    1. I so far haven’t found anything to suggest one way or another whether the first-generation Familia was done by Bertone, although it’s certainly plausible given that Bertone did the first Luce and the Luce Rotary Coupé in that period. Even if Stilo Bertone didn’t do the Familia or the first Capella, those designs have a definite Italian flavor, much more so than subsequent products of Toyo Kogyo’s in-house design studio, which feel more typically mid-seventies Japanese.

  14. I really like that little sidebar referring how to calculate the Wankel’s full displacement. I know Japan has different regulations than the U.S. and that Mazda had no choice to only count one chamber for each rotor (Geometric Displacement) due to extra taxes being placed on “bigger” cars. Either way, I really hope Mazda brings their Wankel rotaries back to the streets, because that awesome RX-Vision concept needs to be on the roads

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