High Treason - 1968 Nissan R381 Chevrolet

In 1966 Nissan Motor Company had absorbed rivals Prince Motor Company. After the takeover Nissan was shocked to find Prince at the cutting edge of technology, way beyond their own capabilities. Especially in terms of engine and chassis technology, Prince was light years ahead of their new master. As the novel discipline of motorsport gained more and more traction with the Japanese public, Prince had been the first Japanese company to come out guns blazing.

Nissan had been hard at work trying to create a weapon of their own to beat Prince’s winning R380 model, but immediately stopped all efforts after seeing what Prince had been working on. The Nissan prototype had been lagging behind the original R380 in terms of raw speed, but Prince had already readied a more refined successor, the R380-II. In response Nissan adopted the R380-II as one of their own, and set out to beat Porsche at the 4th Japan Grand Prix.

The Nissan-branded R380-II failed to make an impression in 1967.

The Nissan-branded R380-II failed to make an impression in 1967.

Despite the advanced nature of the Prince design, the car failed to take the fight to the superior Porsche 906. The Germans had improved their fragile car to perfection, and beat Nissan on their home turf with a massive margin. The loss made Nissan re-evaluate the performance potential of the R380-II. It was clear something much faster was needed to reach the top step of the podium once again.

With this in mind Nissan’s management delegated the task of building a new sportscar to the former Prince engineering team, lead by visionary Shinichiro Sakurai. Sakurai-san understood the importance of breaking boundaries better than anyone, having been responsible for the success of the R380. Up until that time top level Japanese sports cars had relied on 2L six-cylinder engines, but Sakurai-san wanted more, much more.

The Canadian American Challenge inspired Shinichiro Sakurai to think bigger, much bigger.

The Canadian American Challenge inspired Shinichiro Sakurai to think bigger, much bigger.

His quest for power lead him to investigate the Canadian American Challenge, an emerging series featuring radical open top sportscars. Can Am had been steadily gaining attention in the world of motorsport. The series’ howling mad FIA Group 7 formula was the closest thing to “anything goes” the world had ever seen. Any participating car had to have no roof and four wheels. All other aspects were completely free.

Previously the Japan Grand Prix had enforced its own set of regulations limiting engine capacity to 2L and requiring all cars (including convertibles) to sport a fixed roof. Since then the event had gained global recognition, and the FIA had stepped in to govern it. Realizing this meant FIA Group 7 also applied in Japan, Sakurai-san devised a plan to develop Japan’s first bonkers Group 7 machine.

The six-cylinder R380-II was converted to a test mule using Can Am design principles.

The six-cylinder R380-II was converted to a test mule using Can Am design principles.

Sakurai-san ordered his top engine experts to start work on a project the likes of which Japan had never seen before. Using the GR-8 straight six from the R380-II as a template, his men started work on an unprecedented 6L V12. Sakurai-san was adamant the elephantine engine should be able to produce at least 600 horsepower, a totally outlandish figure in Japan and indeed the world at the time.

With his team addressing the engine issue, Sakurai-san focused on the rest of the new car. He knew he had to wait until the engine was ready to be able to design a chassis around it, so he took the R380-II as a starting point for his highly experimental ideas. The car’s sleek bodywork was mutated into a more square and aggressive shape, employing a flattened rear section which abruptly ended. This shape was invented by Dr. Wunibold Kamm as a means of reducing drag, and was known as the Kamm-tail.

The sharply cut off Kamm-tail in action.

The sharply cut off Kamm-tail in action.

Reducing drag was only one point on Sakurai-san’s agenda. After studying the ground breaking design of the Chaparral 2E, he discovered the dark art of downforce. Chaparral’s Jim Hall was the godfather of this principle and had coined the term himself. His studies found the upward lift induced by an aeroplane wing could be reversed simply by mounting it upside down. The reversed force pushed the vehicle down onto the track, which made the tires grip much harder. Hall used his research to great effect in designing the active aero 2E, shocking the racing world at large.

The active wings in operation, Fuji Speedway.

The active wings in operation, Fuji Speedway.

Sakurai-san was intrigued by the American’s pioneering ideas, and moved to incorporate them in his own design. However, he couldn’t resist trying some of his own. Instead of a single large wing as found on the Chaparral cars, Sakurai-san opted for two smaller wings mounted beside each other. During cornering the wings were independently operated by hydraulic struts mounted to the suspension. On the straights the system was dormant, and the wings laid flat.

During cornering however, the inside wing would raise up. This served to counteract the shift in the car’s center of gravity. As the car cornered, weight shifted to the outside, lifting the inside wheels up and reducing stability and grip. With the added downforce from the raised wing the inside wheels were pressed back down again, allowing the car to stay flat and corner much faster.

Even though Sakurai-san had based his efforts around the open top Can Am class, he had no intention of dropping the coupe bodystyle. An open car produced much more drag than a similar closed model, something which he thought didn’t offset the weight advantage.

His perception changed drastically when he received word that bitter rivals Toyota were also building a Group 7 sportscar, which utilized the lighter open top format. The news resulted in the new chassis being hastily decapitated in the final stages of design to counter the Toyota menace. With the change the rear section was further flattened as well, greatly increasing the efficiency of the wings.

The Toyota 7 promised to give Nissan a run for its money.

The Toyota 7 promised to give Nissan a run for its money.

Another shock to the system came not much later. With great shame, the engine specialists informed Sakurai-san that the ambitious V12 engine would not be ready in time for the 1968 race. Panic started to set in on a grand scale. The chassis was complete, but Nissan was without an engine to power it. Asking any of their rivals for help was out of the question, and the Japanese tuning scene was virtually non-existent. Moreover, no one in the country had the capacity or know-how to deliver a 600 horsepower engine period, let alone in record time.

The frantic situation forced Sakurai-san back to square one. He still had to find a way to beat Toyota by any means necessary. Suddenly it came to him. Of course! He had been basing the entire project around the principles of Can Am, save for the engine. With nowhere else left to go, he boarded a plane heading for America.

There he met celebrated hot-rodding legend Dean Moon, head of Moon Speed Equipment. Moon offered Sakurai-san a trio of highly modified small-block Chevrolet 327 5.4L V8’s, which belched out 450 horsepower. Even though the figure was much lower than the 600 he had envisioned, Sakurai-san agreed and took the engines back to Japan.

Nissan had to resort to desperate measures to keep the project alive.

Nissan had to resort to desperate measures to keep the project alive.

Back East, Nissan’s engineers worked their butts off to adapt the R381 chassis to accept the American lumps. Ultimately the three cars were mated to their Chevrolet hearts in time for the race. Fitted with the V8’s the cars weighed in at 836 kg (1843 lbs), substantially more than the old R380. The weight increase was offset by the 230 extra horsepower and an extreme increase in torque. All the extra power was directed the rear wheels by a 5-speed Hewland LG600 manual transmission.

Yoshikazu Sunako, Fuji Speedway 1968.

Yoshikazu Sunako, Fuji Speedway 1968.

The team arrived at Fuji Speedway to face competition from three brand new Toyota 7’s, an equally new Porsche 910, a 906, Lola’s T70 Mk3 and the three remaining R380-II’s, now in private hands. The R381’s were piloted by Yoshikazu Sunako (#18, red wing), Kunimitsu Takahashi (#19, blue wing) and Moto Kitano (#20, yellow wing).

New for 1968 was the tentative introduction of sponsor decals on the cars. The American connection lead to lubricants supplier STP, oil giant Shell, and soft drinks company Pepsi Cola being featured prominently on the all-white cars.

Takahashi quickly ran into problems.

Takahashi quickly ran into problems.

At the start of the race Moto Kitano quickly stormed to the lead, followed by Yoshikazu Sunako. The pair was immediately hounded by one of the Lola T70’s. Kunimitsu Takahashi struggled to keep up, and settled in mid-field. The Lola hounded the two R381’s for a few laps, even taking second from Sunako at one point.

Fortunately for Nissan, their competitor spun off a few laps later, and the feared Toyota’s where nowehehere ot be seen. The R381’s innovative active aerodynamics were helping it along a great deal, but the race was some 480 kilometers long. A lot of ground was left to cover.

Takahashi-san’s car started billowing a lot of smoke late in the race, and seemed out of the running. The other two cars were challenged by Tetsu Ikuzawa’s Porsche 910, which settled in second place. In the end Moto Kitano was able to fend off the Porsche assualt, and retake the Japan GP crown for Nissan. Places 3-5 were occupied by the older R380 model, and Sunako managed to pilot his machine to 6th. The weekend had been a resounding success for Nissan, despite a somewhat embarrassing engine choice.

The Nissan R381 was a luminous idea by daring Japanese designer. Inspired by Jim Hall’s musings, Shinichiro Sakurai attempted to take Japanese sportscars to a whole new level, but fell perilously short of time. An ambitious plan for a ludicrously complex and powerful high tech V12 never materialized, which meant Sakurai-san had to shop elsewhere.

He found his powerplant in the very place he drew inspiration from, the bustling American racing scene. Equipped with shouty Chevrolet V8’s his innovative aerodynamically advanced design took the Japanese motorsport crown back from the invading Porsche force. With the title firmly in hand, the proud designer had a full year to complete the V12, and try to score the first win for a car completely designed and built by Nissan.