Staying Power - 1983 Mazda 717C
In 1982 the Federation Internationale d’Automobile introduced completely new regulations covering all major corners of the motor racing world. Moving away from its numbers-based nomenclature, the FIA switched to using letters denoting each category. Group A covered touring cars and rally cars, Group B redefined the rallying and GT road racing, and Group C was to be the new formula for endurance racing prototypes.
In response to the escalating speeds of the turbocharged monsters introduced a few years prior, a mandatory fuel limit of 600 liters per 1000 kilometers was mandated. With these restrictions in place the FIA hoped to put a stop to the horsepower war. This would hopefully lead new manufacturers to join in, as the virtual engine freeze made entering a competitive new design a damn side less expensive. Another defining feature of the new machines was the closed cockpit, a feature which had slowly lost ground during the 1970’s.
One manufacturer attracted to the new regulations was Japanese renegades Mazda. For the past decade the eccentric company had been busy trying to popularize the unusual Wankel rotary engine in the global car market. Determined to prove the novel powerplant’s worth, sporting division Mazdaspeed had entered Group 5 silhouette racers based on its flagship RX7 sports coupe since 1979 with relative success.
For 1983, Mazda decided to take the project to the next level. Exactly a decade after their debut as an engine supplier to the Sigma MC73, the firm commissioned their first completely in-house Le Mans prototype design. Chief RX7 project consultant Takuya Yura of Mooncraft was appointed to draw up the new racer, which would compete in the lesser Group C Junior class, and early precursor to the modern LMP2.
Yura didn't waste any time time, and took the engine from the final RX7 254i Group 5 car to base his new car around. The unit in question was the third generation, twin rotor, peripheral port 13B, displacing just 1.3L. For its new purpose the mill was fitted with a Bosch electronic fuel injection system, ensuring more efficient combustion and more power.
The tiny screamer eventually managed to produce a hefty 310 horsepower at an agonizing 9000 rpm. It was then encapsulated in a riveted aluminium monocoque, and fitted with a five-speed manual transmission.
Through his experience running and designing the Group 5 RX7’s, Takuya Yura had developed a keen understanding of what was needed to make a car work on the long straights of Circuit de La Sarthe: ultimate top speed. With this in mind he designed the 717C’s bodywork to be as smooth as possible, even enclosing the rear wheels in a single-minded crusade to make the car develop a minuscule amount of drag.
Curiously, Yura also opted to use a very short 2.45 meter wheelbase, and limited the machine’s total length to a positively tiny 4 meters, about the size of a small hatchback. The end result looked like it had been shrunken down in a hot wash, and weighed a sprightly 760 kg (1675 lbs).
Mazdaspeeds’s driving team remained largely unchanged from 1982, with loyal disciples Youjiro Terada (JAP), Takashi Yorino (JAP), Yoshimi Katayama (JAP) and Pete Lovett (GB) continuing their services. The car would make its debut at the Silverstone 1000 km, the final race in the lead up to the main event: the 1983 24 Hours of Le Mans.
Just a single car was entered to test the design’s capabilities. With Pete Lovett an Youjiro Terada at the helm, the little rocket was immediately on the pace. It qualified 21st overall and second in the C Junior class, losing out to the Jolly Club Alba AR2. Sadly the team wasn’t rewarded with the satisfaction of a race finish, as a loose wheel ended their race with a bitter disappointment.
With a second chassis completed, the team took to the French countryside in search of the ultimate glory. The #60 chassis was given to the all Japanese team of Terada, Katayama and Yorino, while the second #61 car received a British contingent consisting of touring car aces Jeff Allam and Steve Soper, joined by British Formula 3 driver James Weaver.
Again the cars clocked very competitive times, having to concede first place to the Jolly Club Alba AR2 once more. But not all was sunshine and rainbows in the Mazdaspeed pit. Complaints from the drivers revealed Takuya Yura had been a tad overzealous with his low-drag philosophy. With a Cd value of only 0.27, the car was indeed incredibly aerodynamic, providing a very competitive top speed of over 300 kph (186 mph).
The downside of this however was that it lacked the downforce necessary to keep it stable through high speed turns. Coupled to the new incredibly hard compound tires Goodyear had introduced to combat the lethally dangerous tire failures seen in 1982, and the 717’s incredibly short wheelbase, this resulted in very lively handling characteristics. A chronic lack of grip and perilously nervous, twitchy behavior made the car a real handful through the fast swooping sections of Indianapolis and the Porsche Curves.
In spite of these drivability issues the Mazda force qualified 42nd and 43rd overall. The British machine proved to be superior by the smallest of margins. Recording a time of 4:05.920, the #61 Mazda was a mere one tenth of a second faster than its sister car. The stage looked set for a riveting prototype debut for Mazda. Nevertheless the cars still had a full 24 hour beating to endure. The struggle had only just begun.
On race day, the full extent of the 717C’s balance issues were starting to take effect. The team’s drivers reported twitchy and unpredictable behavior at any speed, but somehow managed to hold on to the unruly machine. As more and more competitors hit reliability issues and dropped out, the Mazda’s seemed to hold together like a fine Swiss timepiece.
Despite their exhausting handling properties, the cars’ massive top speed advantage quickly made them break free from the rest of the C Junior field. On top of this the tiny rotary proved to be uncharacteristically fuel efficient, allowing for much longer stints. Yura-san’s radical aerodynamic design seemed to be paying off in a big way after all. As night fell, the Mazda’s started to build a decisive lead on the rest of the field.
Near the end of the grueling 24 hour event the 717’s superior speed and efficiency had put the cars firmly in the Group C Junior lead. As their competition dropped like exhausted mayflies, the quirky little Mazda’s just kept on frantically swerving along the endless Mulsanne straight.
The 717C’s impeccable reliability became even more apparent as the pair reached the finish line. As they crossed the line in perfect formation, they became the only Group C Junior machines to finish the event. Every single competitor had given up the ghost hours ago. Therefore the Mazda’s finished first (#60) and second (#61) in class, and 12th and 18th overall out of just 20 finishers. In the process the team collected the first class win for a Japanese manufacturer at Le Mans.
After the glorious victory at Le Mans, the class-winning car was brought back to Japan to compete in the second to last round of the World Endurance Championship and the third round of the All Japan Endurance Championship at Fuji Speedway.
At its home race the car appeared to have lost some of its competitive edge, qualifying fourth in class under the direction of Youjirou Terada, Takashi Yorino and endurance veteran Pierre Dieudonné (BEL). Unfortunately a broken clutch ended their challenge prematurely.
But with their dominant Group C Junior victory at Le Mans, Mazda once again fired a warning shot across the bow of the European establishment. Their message was loud and clear: The Japanese are coming. Be prepared. With the 717C the company kept their word by starting a long dynasty of rotary-powered prototypes, culminating in the legendary Le Mans-winning 787B.