Simanaitis Says

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MAZDA RX-7—ENGINEERING WIZARD YAMAMOTO PERFECTS THE WANKEL

THE WANKEL ENGINE got off to a tough start. An early R&T citation quipped “Winkle winkle, little Wankel,/How I wonder if your crank’ll/Wind up all around itself/And you’ll end up on the shelf.”

Hardly encouraging, German automaker NSU introduced its Wankel-powered Spider in 1964, only to find itself the butt of automotive humor: Instead of waving to fellow Wankel owners, drivers would hold up finger counts of their replacement engines. 

Wikipedia observes, “Engines required frequent rebuilding to replace worn apex seals, and warranty costs associated with installation of the engine in NSU’s second Wankel-engined model [the Ro-80] destroyed the financial viability of NSU, forcing a merger with Audi in 1969.”

Meanwhile, in Japan…. Around 1961, Mazda engineering wizard Kenichi Yamamoto began supervising development of Mazda’s Wankel rotary development. Success in this led to his serving as president of the company (1984–1987) and Chairman (1987–1992). 

Kenichi Yamamoto, 1922–2017. Japanese mechanical engineer extraordinaire, business executive. Head of the “47 Ronin,” the engineering team developing the Wankel to successful production status in the Mazda RX-7.

During Yamamoto’s tenure, he also had the prescience to heed American Bob Hall’s advice in producing an inexpensive, more traditionally powered sports car: the Mazda MX-5 Miata.

R&T’s Road Test. In August 1978, R&T called the newly introduced Mazda RX-7 “an enthusiast’s dream come true.” The magazine had already marveled at the car’s innovations in its May 1978 technical analysis and named it “the Best Sports Car Under $7000” in its June 1978 “Ten Best Cars.” 

This and other images from R&T, August 1978.

It was for good reason that the car warranted all this ink: “… every person on our staff returned from driving the Mazda with glowing praise for its performance, handling, and comfort features—enthusiastic unanimity of that sort is exceedingly rare.”

Beneath all the accessories resides a compact two-rotor Wankel.

Twin-rotor Power. “The 12A Wankel rotary,” wrote R&T, “has a displacement of 1146 cc and, being a rotary, the pertinent measurement is major axis by rotor width rather than conventional bore and stroke…. The rotary design makes for a relatively small and compact powerplant that produces horsepower belying the displacement.”

Above, a Wankel’s four cycles. Below, eccentric rotation in its epitrochoidal chamber.

RX-7 Performance. R&T reported, “Trying to find a comparably priced sports car or GT with equal performance will be an exercise in frustration—the Datsun 280Z accelerates from rest to 60 mph in 9.4 sec and turns the quarter-mile in 17.3 sec at 81.0 mph; the Porsche 924 figures are 11.0 sec to 60 mph and 18.0 sec at 77.0 mph for the quarter-mile test. Other sports car alternatives such as the Triumph TR-7, Fiat 124 and X1/9 lag even farther behind.” 

Corresponding data for the RX-7 are 9.2 sec to 60 and the quarter-mile in 17.0 sec at 83.0 mph.

“Beyond straight-line acceleration,” R&T said, “the RX-7 offers those appreciated rotary attributes of incredible smoothness and quietness along with the ability to easily rev right up to the 7000-rpm redline.”

“Ergonomics,” R&T enthused, “is perhaps the area of the RX-7’s design that best demonstrates how well Mazda did its homework. Everyone rated the RX-7’s driving position and comfort features very high, from the 5-ft. 4-in. woman who wrote, ‘I really feel like I’m part of the car rather than a guest sitting down to dinner in a stranger’s home,’ to the 6-ft. 6-in. man who commented, ‘This is the first Japanese car I have driven which is comfortable for me. Not only is it comfortable, but the seat and driving position rate among the all-time best.”

Conclusion. The August 1978 Road Test concluded by reiterating its subhead: “The Mazda RX-7, at less than $7000 [figure $29,000 in today’s dollar], is an enthusiast’s dream come true.” 

Indeed, the RX-7 continued in three generations into 2002. Kenichi Yamamoto and his 47 Ronin had reason to be proud. ds 

© Dennis Simanaitis, SimanaitisSays.com, 2021 

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