Some stories need a bit of build-up and a certain amount of preparation. Some stories require a great deal of expertise. Some stories are so emotionally charged that you want to rewrite them after reading them several times.

Other stories have a certain sense of magic, and every sentence has to be just right to express the necessary respect.

This is one of those stories. A story that no one else has ever told, and that probably won't be found anywhere in the future either.
Because this is the story of Takeo Miyazaki.

Takeo Miyazaki was born in Osaka, Japan in 1943 and worked at Nissan Motor Co., Ltd. between 1967 and 2003.
He was part of the “Development & 1st Vehicle Testing Department” and “2nd Vehicle Testing Section” in the project of the Nissan S30Z.

Takeo Miyazaki experienced the time of the creation of the Z like no other, shaped it, helped develop it and can still remember this impressive period of his life brightly.

And this is his story:

I was involved in the development of the S30Z at Nissan in the era of the 2nd Vehicle Experiment Division of the First Vehicle Experiment Department at the Oppama Test Course in Yokosuka. During the development of S30Z, I was selfless and said:
"Every day was fun and I couldn't help it!"

In the 1970s, the number of cars increased, and my boss and I insisted that it was important to pay special attention to the operability of the vehicles. As a result, the “Ergonomics Department” was established to ensure safe and comfortable driving.
After that, I was responsible for the “aerodynamics test” which was carried out in the wind tunnel.
It was a time when highways were being opened in various places. To ensure stability at high speeds, I advocated that the wind flow around the body be taken into account and designed accordingly during vehicle construction.

The “220 km/h (maximum 270) wind tunnel for real vehicles” and the “1:6 scale wind tunnel” were completed at the Atsugi Technical Center, but unfortunately one of my biggest dreams, the “Department for Aerodynamic Experiments”, was not realized.
Later, however, even the Japan Railway Shinkansen (bullet train) was optimized in the wind tunnel.

After retirement, I joined the Nakajima Laboratory of Tokai University School of Medicine and was involved in the development of "future ambulances" and "relationship between humanity and brain waves" that can be
used in disaster areas and battlefields (using geostationary satellites).
Currently, I have enjoyed “PC” for 12 years, “Cooking for Men” for 15 years, “Karaoke” for 11 years, “Mahjong Course” for 13 years, “Adult Outing” for 10 year.

My cars were:
1.) Hillman Minx Cabriolet (made in the UK in 1952), at the age of 16–19 years old
2.) Prince Skyline 1500, at the age of 17–21 years old
3.) Nissan Fairlady 1500 (3 seats), at the age of 22–24 years old

Since I started working for Nissan, I only drive Nissan cars, mostly the Skyline, my wife the Sunny.

1952 Hillman (second year of high school)

When I joined the Nissan Motor Company 56 years ago, Nissan had merged with Prince Motor Company the year before and was the highest-volume manufacturer in Japan.*

Nissan had previously launched the Datsun Sports and the first generation Fairlady as a sporty car.
When the development department announced its plan in November 1967 to launch a real sports car that could compete on the world stage, it received a great amount of enthusiasm.

The second-generation New Fairlady concept led to former members of the development team for the Prince Motor Company's R380 race car and people who had studied fluid mechanics at the University of Tokyo joining the development team for the S30Z, and an experimental vehicle (a modified Silvia) with a 1800cc four-cylinder engine and independent suspension was built as originally planned.
After two months, a report from the American research team led to the decision to install a six-cylinder engine, and the design was changed to a long-nosed shape, so the project had to start from scratch.

I joined the company at that time and was assigned to the “sports car group” at the Nissan Oppama Test Center in Yokosuka.

When I was offered a job at Nissan, I learned that there was a park from which I could see the test track.

In the foreground, the winding road is the “handling course” where “dynamic performance” is checked. There was also a “circuit road,” a “standard rough road,” a “waterway,” and a “hill” on the left, and most driving tests can be done here.

If I were to explain the course using photographs, the high-speed endurance test vehicle would go around the “Nojima Bank” in the front of the high-speed circuit in Oppama in a counterclockwise direction at 90km/h, and then accelerate when it enters the straight line, so it would reach a maximum speed of around 150km/h, but because it was a top secret vehicle, it was running with a camouflage cover, so I think that even the driver would have had difficulty telling the vehicle's posture when it was running. Also, the test course in Oppama is long from east to west next to the sea, so on windy days there is a crosswind, but on the south side, where the maximum speed is reached, there is a fence so it is almost unaffected by the wind. The “Natsushima Bank” on the east side is 80km/h, and after a temporary stop at the end of that bank, the car is driven up one gear at a time, reaching about 100km/h before entering the “Nojima Bank” on the front side, but there is a pedestrian bridge on the seaward side that blocks the wind.
Also, as we learned from the wind tunnel tests at the time, the camouflage covers on the van type at this time had an aerodynamic center of gravity at the back, which improved straight-line driving performance.
(The first prototype car also had a large caster angle, so that the car already had good driving performance.)

But more on that later.

When I started at Nissan Motor Co., Ltd. in April 1967, development of the S30Z had just begun, and fortunately I was assigned to the S30Z development group even though I was a new employee.
I was lucky with my boss and was given the opportunity to test a model car in the wind tunnel to make a design decision for the S30Z, which was almost finished.
We were testing with new experimental video and data analysis.
This was a very unusual thing, my colleagues who worked in other departments envied me. I didn't understand everything at the time, but I had made up my mind: “I will definitely make the S30Z a good car!”

The team I joined was newly formed, and I thought it was a bit of a ridiculous department, because we rechecked everything that came to us from other departments.
I didn't understand this double-checking at first.
For the time being, it means that this only applies to S30Z.
There were 5 people for this process to check everything in 3 months.
However, to be able to assess something, you have to learn different things.
You have to familiarize yourself with the work of other departments to qualify for the assessment. So we tackled these qualifications.

Working with skilled engineers

First, Mr. Kamata drove twice on the road course, then he went to the handling course, and after driving twice there, he scratched his head, returned to the road course and drove 500 meters in a zigzag pattern, then went to the skid pad. On the skid pad, which is 50 meters in diameter, he said, “I'm going to turn around, so hold on!” With these words, we did two laps in a clockwise direction and two laps in an anticlockwise direction, then stopped and said: “Now you take over!” He put me in the driver's seat and ordered: “Turn right and left!” As I turned right on the roundabout, Mr. Kamata said: “Step on the gas until the tires squeal!” He shouted!

When I turned right and left twice and stopped,
he said:
“What do you think?”
I replied:
“I feel like the traction is somehow lower when I turn counterclockwise.”
Then he said:
“Somehow! Do you know why?”
I said, “I don't know!”
He said:
“Let's stop!” And over the radio: ‘We're turning back!’ He reported this to the tower.
The tower manager said:
“There are still 20 minutes left, you can still drive!”
“It's useless to do that,” he replied.
I was half panicking, probably because I couldn't answer for what he asked.

We met in the conference room and listened to Mr. K. He said, "There are indeed many prototypes, although I thought they had checked the condition of the vehicles and carried out maintenance in advance. This time it is being hosted by a newly established team, the team is non-expert team of manoeuvrability & stability so that was also my fault that I didn't check it in advance, but the spring constants of the four wheels are too different, and there is no way to evaluate them!"
"If you guys can bring a set of springs which are inspected to ensure desired spring constants, you can ask me to do it all over again! Next time, I want you to be with me again!" He pointed at me and said, "It's been a long time since l've met someone who can step on the gas like that!" he said with a smile.
I was so depressed until I heard that, and I felt like that one word brought me back to life.
I was very pleased with these words, and I was so impressed that Mr. K. was able to show the imperfections of the suspension on the test drive in just a few seconds. I have heard he had a lot of experience, however, his skills way exceeded than I expected. He was a best of the best, carried high skills of professionals, and I was convinced that development of S30 would have been everything all right because there were professionals like Mr. Kamata.

When the S30Z prototype was completed, the full-scale wind tunnel had not yet been completed, but everyone believed that the S30Z's style would make it run as if it were sticking to the ground.
There were several test drives of the prototype, but because they were held on fine days and the car was still covered with a disguise, the test drivers never experienced driving into a crosswind, and the maximum speed at the Oppama Test Course was limited to was limited to around 140km/h, so everyone was satisfied with the S30Z, which was much more stable than passenger cars, and in the meeting after the test drive, everyone, including myself, gave it high marks for high-speed stability.
I thought that the people who would be most aware of the high-speed stability during testing would be the people in charge of the high-speed endurance testing, who test the prototype cars on the public road for 20,000km over a period of several days and nights, so I asked a few people about it, but all I got was the response “The stability is good!”.

Here you can see the wind tunnel a few years later during a test with a 2by2 – or, as it is known in export markets, a 2+2.

Our team did a lot of wind tunnel testing, and actual performance testing on the test track to see how the car performed in the various conditions and models.

For the wind tunnel test, we attached 500–600 tubes to the body. We even had to drill the body to make the holes for each tube.
The car even had a transparent acrylic windshield to better attach the tubes there.

So at the time of the test, the test vehicle was already “old enough” for this process. That's why you can see that the silver prototype in the wind tunnel also has a shark fin at the C-pillar, because the vehicle is from a very early stage of development.

We realized that our S30 didn't look good in terms of drag compared to other cars. This was because too much air is coming in from the front grill, the pressure of the engine bay gets positive then pushing the front up, while air was flowing through the engine compartment to the bottom of the engine compartment.

We realized that the front is raised, the drag will worsen and the amount of air under the car will also increase, creating more lift.

Since the S30Z is not yet roadworthy, we decided to observe the airflow around the body in the recently completed “full-scale wind tunnel”. However, since the airflow around the body could also be seen in the first prototype (with old caster angles and springs), we could not obtain the second prototype, which was still available in limited numbers.
Since it was a wind tunnel, I thought that the suspension would not be of great importance, and started observing the airflow around the body. However, when I viewed it using the stream-filament method, the flow was much cleaner than on passenger cars like the Cedric and the Bluebird.

However, we found that, even at middle range speed (120 km/h), the front of the car was lifted more than 25mm and the rear more than 15mm in the wind tunnel!
But is it because the suspension is an older model? We need to check this, so we quickly gather everyone involved in the development of the S30Z, including the designers, and show them the changes in the vehicle's posture at 120 km/h in the wind tunnel.

Everyone involved had an incredulous look on their faces! Lucky enough, we were immediately able to have a second prototype car, which was supposed to be completed the next day.
When the second prototype car, which had a different suspension, was put into the wind tunnel for testing, it was found that the front of the car was raised by about 20mm and the rear by about 10mm, so the suspension changes had reduced the amount of lift.
The team leader and chief engineer had studied aerodynamics, but they said they couldn't think of any immediate applications for cars. “Then let's try it out in practice! So, they decided to “see how the cars currently on the market perform”, and used the Bluebird, Skyline, Porsche, Jaguar, Corona, etc. in the experimental department to take side-on photos of the cars' postures during actual driving on the test course and in the wind tunnel, from 20km to 120km per 20km, and compared and examined them.
As a result, it was found that all the cars were floating up to the same extent as the S30Z, and that the wind tunnel test showed a slightly greater degree of floating than the actual driving test. When we investigated the cause, it seemed that the “ground effect” was having an effect.

In real driving, the difference in speed between the ground and the car is the same as the speed of the car, but in the wind tunnel, the car is on the ground, so the difference in speed is zero, and the wind flows between the car and the ground, so it seems that the effect is felt up to about 30mm from the ground. So, we put a board under the tires and raised the car, and as we changed the dimensions of the board and took measurements, we found that at 25mm, the lift was almost the same as in real driving.
At the same time, the team leader's aerodynamics ideas led us to try measuring the pressure around the S30Z's body, so we asked the Prototype Department, who had always been so helpful, to change the windows to acrylic and try measuring the pressure.
It took a week to drill all the hundreds holes of 1mm diameter in the car body and attach the pipes for measurement, and the pressure measurement involved getting into the car set up in the wind tunnel and connecting each of the 1mm pipes to the pressure measurement device one by one Since there was no pressure gauge that could quickly stabilize the readings, it took two minutes to measure each point, so it took three hours to complete the measurement for one ride. It was said that the electricity bill would be 2,000 yen per minute if the car was driven at 120km/h, but we managed to finish the measurement after two days and nights.
Looking back, it was a lot of work, but since it was an entirely new field, everyone was able to complete their assigned tasks with enthusiasm, and when we finished, we were all smiling, looking forward to the data that would come out.
Through our efforts, we were able to confirm numerically the cause of the car body lifting when it was driven.

Although this photo still shows a model of the car, it is easy to see how the individual pipes lead into the measuring devices.

Simply explained, with a car, the cross-section of the wings of an aeroplane is more complex, but the air flows faster over the car than under it, so it is pulled upwards by the pressure difference.
This had been predicted, but given the design of the car, everyone thought that the wind flow over the top of the body was so nice that it should be held down a bit more. The other front end floats more upwards because the car engine is water-cooled, but at that time the technology had not yet been developed enough to cool the engine with only the circulating water (coolant), so the engine compartment also needed wind. So if the engine compartment only had an opening for the radiator, only warm air from the engine would enter, which would cause the carburettor to overheat. Therefore, it was common practice to also let in outside air from the area around the radiator. This is because the air in the engine compartment, in addition to the air flowing under the body, must be let out from under the body, thereby increasing the pressure in the engine compartment and creating a force that pushes the vehicle forward. (This problem does not occur in rear-engined Porsche models.)

The sports car team

Rather than waiting the three months it took to build the first prototype, the team borrowed the instrument panel and seats from the prototype department, built them into a rack, adjusted the driver's seat, and checked the visibility of the meters and the operability of the switches. Those tests had been traditionally done in each design process. But our team did testing by our own standards in early design stage. No
other department had tested like our team before, so our effort was recognized in Nissan.
As described above, this was the birth of the "Ergonomics Department".

As a result, I became involved in all aspects of the S30Z's development, from the practical evaluation of the S30Z even before the prototype was built, to its aerodynamic properties in the wind tunnel and its stability at high and low speeds.

The development of the S30Z was Nissan's first full-fledged sports car and involved a whole range of new technologies.

The most difficult part of developing the S30Z was the four-link suspension, which was a first for Nissan, as well as the tuning to optimize dynamic performance and optimize aerodynamics to prevent the body from floating and ensure stability at high speeds.
We often had to experiment, even after punching the timing card, but by the time the S30Z was finished, all those difficulties had been replaced by happy memories.

Back then, the desire to make a good car was stronger than the desire for money.

The vehicle development process

Vehicle development is carried out in the following sequence:
draft ⇔ draft ⇔ (prototype) ⇔ experiment.

*The design is reviewed after the design phase. If necessary, a change to the design is requested.

*The car produced as a prototype is reviewed in the experimental phase, and if the target values are not achieved, a change to the design is requested. A report is also submitted if the target values are achieved.
The designers write on the drawings what they think is good, so even if the result is cautionary, they don't want to change the design.

Normally, development time is 3 years, but for the S30Z it is 2 years, so the target values have to be achieved quickly.
We also want to make the car as good as possible, so we want an OK and not a CA (Cautionary).

For example:

On the S30Z, the castor angle of the front strut on the first S30Z prototype was too large, making it difficult to handle even for men at low speeds due to the heavy steering. So we submitted a request to change the castor angle during the test, but it was ignored, probably because young men would somehow be able to cope?

I think that the S30Z is a sports car, so the design emphasized straight-line driving and increased the caster angle. Although I don't like it when other departments tell me to change something, the S30Z's driving stability is about twice as high as other cars. And since a weight of more than 6 kg is almost a no-go, I had a woman drive the car into the garage to make sure the design was changed. I filmed the situation in which she was unable to park the car straight even after 5 minutes, and sent the footage to the design manager in reverse order of the usual report.
The effect was outstanding and approval for the change was granted immediately. However, because the person in charge of the experiment was also in charge of the ideal caster angle investigation, some tricks were also needed for a car with a short development period like the S30Z.

As a result of the test with the caster angle changed, the restraining force during manipulation was slightly higher than the 3.5 to 4.0 kg of other cars, but considering the straight-line performance of the design, the caster angle of 3 degrees (restraining force during manipulation: 5.1 kg) was judged to be the best.

I believe 5.1 kg was the heaviest weight for a car at the time. In the U.S., where many cars have power steering, there was a joke that S30Z owners would get up in the morning, stretch their arms with an expander, and then get into their S30Zs.

Design and planning could be done by one person, but for experiments you need a “vehicle”, and whether the test items are okay or not, you need measurements. So for the above-mentioned test of steering force, you need at least 5 people, including the meter, 3 people for measurement, and 2 people (or more) for driving, so you need time and manpower.

There are dozens of points to check. To complete the development process in two years, we had no choice but to increase the number of employees and get support from other vehicle development teams. Normally, we don't send our best people to support, but for the S30Z, the best people from each model team came at their own request to help, so we were able to complete it in two years with a nearly satisfactory performance, but to be honest, I would have liked another six months.

And of course there were things that could not be completed in the beginning.

An exhaust for the Yamaha S20 engine:
The exhaust was so good that it felt more like an exhaust system than a muffler, and we felt that acceleration performance increased by about 20%.
Since we had a technical partnership with Yamaha, we wanted to use it on the S30Z.

Cooling system weight reduction:
The cooling system had to be made lighter because it weighed over 30 kg

Movable front spoiler:
This was later adopted in the Skyline, but we had proposed it too late.

The engine choice:
The S30Z was originally planned to be launched with a 1800cc four-cylinder engine, and there were several design candidates. A Silvia-class chassis with four-link suspension was also planned, so a test car with Silvia four-link suspension was built. However, due to demand from North America for an engine of 2000 cm³ or more, the engine was converted to a six-cylinder at short notice and the design had to be started from scratch, which is what actually shortened the three-year development period to two years in the first place.

The design of the S30Z

Coincidentally, the group that designed the S30Z was the same group that normally designed the Emperor's official cars and special vehicles for parades, etc. I think we were fortunate to be able to create a bold new style without being constrained by past designs.
Even today, I still like the clean, simple shape of the S30Z the best.

The reason the S30Z turned out to be such a great car is that in the development department, the entire department worked together enthusiastically, crossing the boundaries between the different models, instead of getting caught up in the usual competition between model groups...
No, I think it was the result of all the employees of the Nissan Motor Company working towards a single goal.

There were two types of S30Z designs, and an open version was also planned for the targa-type.
The experimental targa-type car was produced in the first prototype phase, but development was discontinued due to inadequate body rigity.

Coupe (1/4 model) - wind tunnel experiment

Targa-type – open and closed roof (1/4 model) - wind tunnel experiment

To avoid giving the impression that it is a sports car, it is equipped with a light, van-like canvas roof during the tests.

When developing the S30Z, it was important to us to be able to consider and compare it to other vehicles.

Shown here: A comparison between the S30Z, Porsche and Jaguar – the aim was to measure how long it takes to get in and out.

The idea for the all-new nose came from our group, which at the time used wind tunnel test equipment for aerodynamic experiments, and not from the design department (sculpting).
During the maximum speed test conducted at the Japan Automobile Research Institute's Yatabe test course before the S30Z was officially certified, the 240Z (2.4-liter engine for North America) and the 432 2.0-liter engine for the domestic market of Japan) could only achieve an average speed of 187 km/h, which was disappointing, and the car's stability at speeds above 160 km/h was unsatisfactory.

Even when I drove the Porsche Carrera at 200 km/h over the steep curve in Yatabe, the vehicle was so stable that I could take a picture with one hand, and I wanted to surpass that.
Aside from the usual vehicle development tests, the plan was to market the S30Z as “the first domestic car with a drag coefficient (CD value) of under 0.4”, which was a hot topic in the automotive industry at the time. Calculations showed that the drag coefficient could be reduced to 0.388 if the minimum air volume flowing through the radiator was increased by 20% using the heat resistance test department.
As a synergistic effect, the pressure in the engine compartment decreased and the probability of the front of the vehicle lifting off the ground was reduced, thus also improving stability at high speeds.
However, the calculated top speed was 193 km/h and even with an additional rear spoiler it was only about 196 km/h, so the calculated 200 km/h was not reached.
The front spoiler has an excellent effect on high-speed stability, but the top speed drops a little.

But the sales department at the head office gave their OK when the CD value dropped below 0.4, but none of us in our group were satisfied with it. After finishing our regular work and stamping our time cards, we gathered in the wind tunnel lab and came up with the idea of “exceeding 200 km/h”. We decided on the “front nose” design, which was based on data from previous wind tunnel tests and had the effect of reducing the amount of wind passing over the radiator at high speeds, as well as that of a front spoiler. We made the front nose ourselves by gluing pieces of glass wool together, and when we measured it, we got a CD value of 0.386.
I can still clearly remember everyone's faces at that moment. (But we will come back to this topic later.)

No one shouted “Wow!” or “We did it!”, but everyone looked so happy and confident that they had achieved what they set out to do.

This overtime experiment was later discovered, and we all had to write letters of apology for “operating the wind tunnel device, which costs 2,000 yen per minute, for over 50 hours without authorization” (from the company) and for “continuing to work after punching our time cards” (from the labour union).
Fortunately, it was not made public because it was said to have been done “out of enthusiasm.”

Immediately after the announcement of the release of the S30Z, we took the “front nose” we had created to a test drive event at the Yatabe Test Course, attached it to a 2.0-liter domestic market engine car, and had executives from the head office and sales department drive it.

People took it for a test drive, it reached over 200 km/h and was very stable at high speeds, so it was particularly well received by the people from the sales department. After some design work (modelling) to match the front with the bumper, etc., it was finally launched on the market.

Classification of the engine specifications and the driving pleasure of the S30Z

The S30Z has a wider variety of engine types than other (Nissan) cars.
The L-type engine is available in 2000cc for the domestic market, 2400cc for North America, and 2400cc (non-exhaust gas regulation) for Europe, as well as the 2000cc S20 type also for the domestic market.

The model I found easiest to drive and liked the most was the S30Z, which is equipped with the 2400cc engine for the European market.

The reason for this is that it has plenty of torque at low speeds, making it easy to drive in the city, and the slightly stiffer suspension is well-matched to the weight of the car without being overpowered.
The second most popular model is the 2400cc model for the North American market, and the third most popular is the model with the 432 engine (based on the Prince S20 engine).

The 432 engine is fun on mountain roads, but the clutch is stiff in the city, so it can be a bit exhausting.

left: Prince Motor Company R380 2.0L, 432 engine (for racing)
right: Prince Motor Company R380 - The base model has the S20 engine.

The first prototype of the S30Z was not going to be ready for another three months, so while I was waiting for it, I was able to get lessons from people with expertise in different areas, and I was really blessed with good leaders.
For driving (judging driving stability, manoeuvrability), Mr. Kamata, whom to be regarded as the most accurate and sensitive at Nissan, and he was the only person with an A1 rank in the entire of Nissan came to teach me quite often beyond the normal scope of his work. I received instruction on the airflow around the body of the car from Mr. Sakamoto, who conducted experiments on the airflow around a quarter-scale model of the S30Z at the University of Tokyo on behalf of Nissan.

I was able to receive instruction on heat resistance from Mr. Sakata, who was in charge of racing cars at Prince Motor Company.

I received three months of one-on-one training, which is not normally given to new employees, and was treated in a way that my colleagues from other departments would have envied. Although I didn't understand anything, I was determined to “make the S30Z an absolutely great car!”

The long-awaited S30Z prototype came to our team

What will you do in two weeks? Before the prototype came in I had to decide what to do, but there are too many confirmation items such as rentability and driving ability, practicability in the engine room and undercarriage. "Can you accurately judge non-specialized fields in 2 weeks?" There was also anxiety, so we asked each specialized department related to the content we confirmed and asked for cooperation, and received support from each department for only one day.

In order to increase the test time, as a two-shift system of day and night, at that time, I worked 6 days a week, so I took the last 4 days in summary, and I couldn't take the car outside (test course) during the daylight, so the driving test was a night shift. During the daylight, the engine, suspensions, body style and manoeuvrability, rigidity, etc were tested in the building. I received the support of 8 people in 8 days from each specialized departments.

After all, it depends on the management skill of the team leader, but this is also the personality of the team leader. Each department head doesn’t want to send a team member to other department as usual. However when the person who was nominated heard that it was "S30Z evaluation", there were many motivated people came to support and those people had garnered much respect from his peers because of his amazing skills.
This is also because everyone in the development department knows the team leader's daily efforts and enthusiasm.

In the test work of the prototype car, I decided to participate in the performance and manoeuvrability test on the second day on the night shift with my boss.
It was OK to give the hope of "I want to take off the fake cover and run naked" from Mr. Kambara (helping from other department.) However, even at night, in order to run the super secret S30Z naked, you can not only turn off the lights of the test course but also put 10 watchmen around the course for security. Also, in "Nojima" (the small hill where the photo of the test course was taken) with an observation deck nearby, the company's security guard was placed. The running time was only 30 minutes, and the conditions were strict, and the procedures were much more difficult for those who worked during the day.

On the day midnight, the fake cover was removed, and the preparation was completed, and Mr. Kambara was driving, and when I thought that my boss would naturally ride in the passenger seat (the prototype Z was 2 seater), suddenly I was nominated by my boss, saying, "You were a racer in your college so you should get on."
When I was about to say, "Get ready, let's go! It's only 30 minutes!"
Mr. M., the test track manager (this person has absolute authority on the test track!), gave us instructions over his radio.
And if it's only for 30 minutes, you can't waste a minute, so you sit in the passenger seat.
(I just told the team manager that I was racing!)

What happened with the prototype cars.

I don't know what happened to the prototype cars after the test. I can only say that it was a strict rule of Nissan that the cars were completely destroyed after the test. The body panels were smashed and drilled into the engine block and pistons by a large Hummer. Then they were picked up and crushed by certain employees. However, there were some exceptions. Some engines and drive trains were saved for personal use and sold in secret.

I bought a used L24 from a well-known store in my town and installed it in my 1984 Skyline GT. I was surprised that the L24 was removed from a car that was never sold to the public, and the engine was so beautiful that I had missed it so much when I sold the car.

Time was short and problems were encountered. Among other things, there were quality issues with coil springs.

I also talked to the section chief of the prototype about the spring constant, but I get an answer that it is impossible to check the quality of the spring just by assembling the predetermined parts.
Is the spring constant of the prototype car with high-speed endurance and bad road endurance that I've already been running for a month? When I asked Mr. K, "In the test course, I only run counterclockwise, so the driver won't notice even if it's not right!" It was about that.
After consulting with Mr. K, I will ask "NHK" in Yokohama, which produces strut springs, to order 10 front and rear as soon as possible, and I will pick them up in two days.
I was surprised to measure 20 pieces while learning how to measure the spring constant from a person with performance group.

There were only 4 out of 10 for the front that met the front regulations, and there were 3 out of 10 for the rear that met the rear regulations, the rest were scattered outside the regulations, but when I asked Mr. K, "Nihon Hatsujo" is also in the prototype stage, so the probability of the spring constant is less than 50%, but the performance group will also do a test by changing the spring constant, so he said that he would like to receive something outside the regulations.

When I went to "Nihon Hotsujo (NHK)" and asked how to quench it, it was said that the hardness was determined by the quenching time, and if you get used to it, it would be about 80% probability.
In the measuring instrument of the experimental part, it takes about 15 minutes for those who are used to measuring the spring constant, but I found that "NHK" can do it in 3 minutes, so in the future, it is OK to ask you to measure the spring constant before delivering the ordered items from Nissan.

As a result, from now on, there is no need to worry about the spring constant even for prototype cars.
Still, the performance group always disassembled the undercarriage and checked the spring constant before the test.

Test results

The next week, Mr. K and I took the ride of S30Z with the correct spring constant for about 2 hours with a disguised cover and evaluate the performance.

1.) Overall, the performance is balanced with the prescribed spring.

2.) The straightness is good, but the handling performance is not very good. The caster corner doesn't fit the car (as a sports car)

3.) The power weight ratio is matched with an engine with torque.

4.) Dunlop is right for the tyre, but it's a little too soft (consideration with Yokohama).

So, 2.) was close to impossible, but it was a CA (Cautionary)

The data of each department that others are in charge has also been collected, and what needs to be changed in the end is:

1.) The caster angle is too large, and it is difficult to handle on the paved road (request to change the caster angle. By reducing the angle, the handling performance will also be improved.)

2.) The spring outer diameter of the strut is thin and unpaved, and "chattering sound" is made (diameter change request)

3.) The opening and closing of the door glass is heavy at high speed (need reinforcement of the glass jig).

4.) Pick up the sound of the seams of the pavement (The sound is louder than the passenger car. Tyre selection!).

5.) If you try to put a lit cigarette on the ashtray, the ash will fly.

The other cases have increased by about 40, but Including #3, those were regarded as "things that can be changed until the release".

1.) and 2.) and 4.) seemed to affect the body press and other undercarriage parts, so we decided to make a request as soon as possible. (5.) was in charge of the design department and ours, but we can't change it from now on)

There were many things that overlapped with the defect reports already issued by each specialized department, but in order to speed up the change, it was decided to submit a change request report.

When the caster angle and spring shape change, the manoeuvrability will be from scratch, but we decided that it is okay because it is a department where Mr. K is, and our team said in the test of the actual car wind tunnel (recently the measurement device was completed), "S30Z is in a crosswind at high speed. I decided to work on confirming and improving the data that "it is not strong".

There were a lot of evaluation items that were good, but I think those who are riding the S30Z know about them, so I won't write it here.

Story about a Porsche 911 front spoiler

We were all so passionate and full of energy to develop our S30, everyone bought and read overseas car magazines, even it wasn’t cheap for young men. So our team pooled together to buy European car magazines. In a recent issue, we found a photo of the winning car in a Porsche race, which had a front spoiler that was unheard of before according to Japanese common sense. At that time, the front spoilers of racing cars generally had a 45-degree overbite shape, as seen in the photo below. The idea was to utilize the force of the wind hitting the moving car, and since a 45-degree angle would cause half of the force to be downward, it was hoped that this would have the desired effect.

However, the front spoiler on the Porsche Carrera was mounted vertically.
Our chief engineer seemed to sense something when he saw it, but the four of us, including myself, were arguing about whether it was effective because the Porsche didn't have a radiator in the front. In the summary, the chief engineer said, “I think that the vertical spoiler is a new idea that uses pressure (air pressure) instead of just using wind pressure to suppress the front. The team decided to try it out to see if it would also be effective for cars with front radiators. The Shimadzu three-component force measuring device, which was being installed in the wind tunnel at the time and could measure the coefficient of drag (CD) of a car, had also been installed, so it was decided to use the car that had been used to measure the pressure on the body to also measure the pressure and coefficient of drag (CD) around the front and in the engine compartment.
We will measure the Porsche 911 and S30Z, which we purchased for performance comparison.

The results were excellent, with the Porsche fitted vertical front spoiler like the one in the magazine.
When we looked at the lift, it was about 5mm even at 120km/h, and the drag coefficient did not increase much. In the confirmation test, we also tried attaching a spoiler at a 45-degree angle, but the vertical type had the same effect even though it was slightly smaller (ground clearance).
At this time, the Porsche had a front spoiler the size of a race car.
We also tried attaching a vertical-type spoiler to the S30Z, but the lift was 12mm at the front and 7mm at the rear, so it didn't have the effect we had hoped for.

A larger spoiler would have been effective. But since it was not a racing car, the ground clearance of 150 mm had to be maintained, and it was not possible to make it larger.
At that time, the bumpers at the service areas on the expressways were about 150 mm high, so the spoiler would have been damaged if the car had been parked with the front facing forward.
When checking the pressure values around the car, it was found that the pressure in the engine compartment increased significantly. This is because a lot of wind entered the engine compartment through the front spoiler, and the increased pressure pushed the front of the car up. We found that the front spoiler was only half as effective.
Our wind tunnel test results show that the vertical front spoiler on the Porsche race car is effective. Although the vertical spoiler generates drag, the air flowing over the car's underbody is reduced even more, reducing the pressure on the car and pushing it down. As the pressure on the underbody decreases and the pressure on the rear increases.
The spoiler's drag coefficient is also halved. The result is a significant improvement in high-speed driving stability.
Four months later, at the JARI test track in Japan, the aerodynamic performance of the S30Z was improved by the measures described above and the results were confirmed in a comparative test drive.

Returning to the S30Z measures: The S30Z also benefits from the air intake reduction, but the question is how much air can be blocked without affecting engine cooling.
So we contact the heat-resistant materials department, which conducts engine tests, and they tell us the required amount of air at the respective speeds for the 432Z, 240Z and 2LZ.
After that, we blocked the vents around the radiator to reduce the amount of air entering the engine bay by 20%. After that, we measured the body lift. We also observed the airflow in the engine bay and found that the air coming out of the radiator immediately rushes to the bottom of the car, so it doesn't circulate well in the engine bay. We solved this problem by adding a baffle plate from the engine to create a smooth airflow, thus eliminating heat build-up in the engine compartment and reducing the amount of air around the radiator.
The bushes on the suspension were also reinforced and the body was raised at the front by about 9 mm and at the rear by 5 mm at 120 km/h. Thanks to new measurement methods, we were able to express in figures the values that had previously only been determined approximately, which represented a major advance. However, since the introduction of the “calculating machine” was delayed, it was very laborious to read the figures at 12 points per speed, transfer them to paper and use a mechanical calculating machine or a slide rule when calculating with roots.

We took data by swinging the S30Z on the turntable 30 degrees to the left and right, and it was at this time that we first realized that the aerodynamic center of gravity of the S30Z was in front of the center of gravity of the car. (From now on, we will work with the design department to measure the aerodynamic center of gravity at the scale model stage and design the car so that it is closer to the center of gravity.) We also examined the rear spoiler, and as a result, we were able to reduce not only the design but also the air resistance, and we were able to confirm an unexpected effect.
As a side note, when an executive came to see the S30Z lift off, he saw that I was calculating the drag coefficient (CD value) by hand, and he bought a calculator made by Sharp, the company that made the first electric desktop calculator in Japan. (At the time of its release, it cost over half a million yen, which was enough to buy a Bluebird.)

The aforementioned “automatic calculator” was installed four months later, and although it was two meters high and 50 cm tall and said “IBM computer” on the nameplate, the data was stored on a punched tape, but the data was calculated and output on roll paper, so the tests were about twice as fast. But enough of the digressions.

The effectiveness of the vertical spoiler was confirmed, so we asked the research institute that conducted the race (Y51: a facility that researched Nissan race cars) and the racing club that Nissan supported to bring their passenger car race cars, and we showed them the effectiveness of the vertical spoiler. The buck-toothed front spoiler was a shape that ruined the style that the manufacturer had put so much effort into designing, so we openly told them that we wanted them to replace it with a vertical spoiler.
From then on, the front of cars in racing quickly switched to vertical spoilers.

At one time, it even had a front spoiler with zero ground clearance on an F1 race car. Skyline (R32)

The movable front/rear spoilers (which are stored at low speeds to maintain ground clearance) were tested on the S30Z, and they had the effect of allowing stable driving at 160km/h, but unfortunately they were not sold.

From around the time the Meishin Expressway was completed, the “drag coefficient (CD value)” was sometimes discussed in Japanese car magazines by experts. Many experts said that a car with a small CD value was a good car, and it seems that the consensus was that cars with a small CD value also have good fuel efficiency!
The calculation of the “drag coefficient: CD value” is done by dividing the “air resistance value” that the car receives when it is running by the “projected area” seen from the front of the car, but I think it is nonsense to compare this CD value between different cars. However, since the CD value is often advertised in magazines, car companies want to make it a selling point, and there was a request for the S30Z to have the smallest CD value of any car sold in Japan this year.
A three-component force measuring device was installed in the full-scale wind tunnel, and an automatic calculator (computer) was also put into operation, so when we measured the CD value, it was found to be over 0.4, which is the same as a passenger car, despite its appearance. We were surprised by this, but we also had measures in place to prevent the body from lifting off the ground, so we decided to do our best to get it ready for sale.

When you take engine performance out of the equation, the cars with the lowest air resistance have the best fuel economy, so even if the CD value is good, if the air resistance is high, the fuel economy will be poor.
To give one example, in the 1000cc or less race at the Suzuka race track, the Honda S800 would win in races over short distances, but the Toyota Yota 8 would win over longer distances.
This is because the Honda S800 has more power, but the Toyota 8 has less air resistance, so it only needs to refuel less often to win.
At the time, there was no device that could measure “air resistance”, but it can be estimated that the Toyota Yota 8 had a fairly low “air resistance”.
A car with a low CD value has a smooth flow of air around it, and can be said to be a beautiful car.
Even if the CD value is lowered as a measure to improve fuel efficiency or aerodynamic properties, it is worthwhile. However, the S30Z is a sports car with a sleek appearance, so we can understand the company's desire to advertise its CD value. Therefore, we have set ourselves the goal of becoming the first domestic car to achieve a CD value of 0.4.

Headlight cover

The design department suggested a light cover, and when I tried filling it with clay to make the shape of the light cover, the CD value dropped to 0.399, but since the light cover is planned to be an optional setting, I aimed for a CD value of 0.40 or less for the standard car.
When comparing the 2LZ, 432Z and 240Z, it was also found that the North American 240Z had the lowest CD value, and the reasons for this were 1) The engine is heavy, so it is difficult to lift up. 2) The radiator is thick, and the pressure in the engine compartment does not rise much, etc., and by taking the above measures with the North American 240Z, it was possible to achieve a CD value of 0.398 with a normal car without a rear spoiler.
Unfortunately, the CD value of the 2LZ model sold in Japan was not able to drop below 0.40 without a rear spoiler. (After sales, the radiator area was modified to achieve a CD value of 0.398.) The continuation of these modifications led to the creation of the ZG specification model with a grand nose.

Story about testing targa-type S30

They thought they could sell the car, but there was a serious problem: a crack in the C-pillars.
I know that even today, people wonder why the panels on the C-pillar of the S30Z are joined like that.
That's because of the targa-type model. Nissan had to have a universal design for the body panels for cost reasons. That's why the connection was made that way. I had seen that the engineers had such a hard time solving the cracking problem on the targa-type model.
We actually tested some of them. But one day, one of them started to crack at the top of the C-pillar joint during a 2000 km test on the “Belgian road test” track. The Belgian road test track is very demanding on the body structure. A 2000 km test is equivalent to almost 100,000 km of actual driving.
Nissan stopped production of the targa-type model due to the cracking problem, but had to use the same design of body panels and joints for the normal roof model.

As an engineer in the vehicle testing team, we said NO to the connection. But that was not taken seriously. Only one in five cars with a normal roof had no visible cracks after the Belgian road test, and then the connection and body parts were used for production.

One day we inspected a used vehicle with 100,000 km on the clock that had neither a crack nor any paint damage on the C-pillar. We were relieved to see this, and the Belgian road test was well-designed for the stress on the body structure.

It may not have been the best method to see paint cracks on the C-pillar of some cars with the coupé body.

Why lead was used to connect the gaps and not putty was not answered at the time.

This is just a little aside, but right after the S30Z was announced (December 1969), the 2nd Vehicle Test Department were conducting a “public high-speed driving test” on the Tomei Expressway over a distance of 50,000 km, using two cars: a 240Z (blue) for North America and a 2l (yellow) for the domestic market. As Mr. K's team was in charge, I was often called on to help out. We would leave Yokosuka/Oimachi test center at 8am, and depending on whether the passenger was from Nissan or Nippon Sharyo, we would enter the Tomei Expressway from Yokohama or Atsugi Interchange, and after driving about 450km and turning around at Hamamatsu-Nishi Interchange, we would return to Yokosuka/Oimachi T/C at 5pm. you need to be driving at around 140km/h to make it back to Yokosuka/Oimachi T/C by 5pm. We finish our inspection by 6pm and hand over to the night crew (usually 4 people) who leave at 8pm.

At the time, there were few trucks using the Tomei Expressway during the day, and it was possible to drive at 160km/h after passing Gotemba. The police cars at the time were Cedric or Crown, and they were generally driving at 120km/h, so there were times when I was able to catch up with them.
If that happened, I would be out of time and not be able to stop at the Hamamatsu Service Area for an eel bowl, so I would have to run without a lunch break, with a loaf of bread in my pocket.
I also experienced the good suspension of the S30Z. At the time, the road around Matsuda, just before the Gotemba area of the Tomei Expressway, was a road with a tighter left-hand bend than it is now, and I was sitting in the passenger seat of the 240Z, but when I looked behind me just before entering the bend, I saw a Honda S800 following us. I opened the window and waved my hand down to tell him to slow down, but he must have thought it was only a slight incline and was fine, so It continued to follow me into the curve, but then it skidded sideways and hit the guardrail. (I think it was going about 95km/h.) The S30Z was able to take the curve without any problems. The crosswinds were also no problem at about 120km/h.

At that time, there were still many dirt roads outside cities in Japan, apart from toll roads, so I adjusted the suspension to be a little softer, but if the road conditions were the same now, I think I would have adjusted it to be harder.

I believe there were 6 people involved for the test ride in Europe in mid 1970 to early 1971.
Mr. Takei was a chief, and Mr. Kamata was there too. Mr. Kamata whom to be credited as an A1 qualified test driver.
A1, is the highest rank in Nissan who has outstanding skills for evaluating feelings and handling character of vehicles.
Actually, he is the one who took me as a buddy of the handling evaluation, and he pointed out the imperfections of prototype coil springs in just a few seconds.

Of the six people, two were selected from the Oppama Experimental Department to participate.

In Europe, there are highways with speeds of up to 200 km/h, and the L24 engine is designed for 200 km/h. Therefore, our team also discussed what kind of suspension should be used for the car we would take on the expedition.

It was decided that the suspension of the S20 engine specification, where driving performance was most important, would be the best. Therefore, the suspension of the vehicle was modified to the North American specification, and before shipment, an initial test drive of the vehicle to the European specification was carried out on the test track in Yatabe, which was quite well received. The test car was sent to the Netherlands.

The expedition team was based at Datsun Nederland, where they evaluated the car's performance. However, the report they received two weeks later was not so positive, with the comment that “the S20 specification suspension was too soft, and it was impossible to reach the top speed”.

I was in Japan to co-operating for the Euro spec development. When I got the request from the team in Europe, my team and I selected alternative parts to be seemed proper and shipped to Europe.

What made me annoyed was, their request was always not seemed well considered.

Soon after the test began, they requested much softer coil springs. I sent three different sets of springs and shock absorbers to them.
3 weeks later, they requested a much stiffer suspension set up because the previous ones were too soft for the road.

Later on I became to realize that they didn’t test on highway but in town with the stiffer set up. Also, they didn’t test in town but on highway with the softer set up.

My colleague also felt uneasy about their requests and said, "Let’s send the one as hard as hell!"
I took his word and decided to send the ones which were applied to the Works Monte Carlo cars.
You know what they replied? It was too stiff!

But finally the team reached what they think good. And Datsun Netherlands said "Excellent" in early 1971.

It was a story of old days, everything was like that in communication, not like internet world today.

About the European specifications

The S30Z was announced in October 1969 and a 50,000 km endurance test was started on the Tomei Expressway between Yokohama and Hamamatsu, using two cars, the L24 from North America and the L20.
The S30Z was designed for two passengers, so one person would be the sole driver, while the other person could be a passenger of the development department's choice.

At that time, the Tomei highway had no sound barriers, and when driving out of tunnels or crossing hills, there were about 40 instances of crosswinds on the way to and from Hamamatsu.
However, with a maximum speed of 100 km/h, there was no cause for concern, and the highway was considered to be one of the most stable in the country.
In the Tomei Endurance Test, it was fine to accelerate to 120 km/h when overtaking due to the legal speed limit of 100 km/h. However, when the speed inevitably exceeded 140 km/h depending on driving conditions, some people felt uncomfortable because when there was a crosswind, the front of the car would be pushed toward the wind direction.
However, since this was above the maximum speed allowed in Japan, it did not improve the evaluation.

The high-speed, long-distance vehicle can reach speeds of up to 150 km/h on the Oppama test course before entering the curve, but since the course was surrounded by walls, there seemed to be no problem in the left-hand direction.
Even in our team, when we finalized the confirmation of the car's performance before it went on sale at the end of September, we conducted a right-hand drive test on the Oppama test course, which is not normally possible, and we confirmed that the car started to sway in a strong crosswind at a speed of about 125 km/h. We had already come up with several countermeasures, such as front and rear spoilers and a blunt nose, but we were still considering reinforcing the suspension as a countermeasure without changing the car's appearance.
Even in Japan and North America, where the car is sold, the maximum practical speed is around 120 km/h, so no problems were reported.

To improve high-speed stability without changing the appearance, the only options are to change the stance of the car or stiffen the suspension.

So I decided to lower the front by 15mm and change the stance to horizontal when I stop for photos and to 100km/h when I drive.

*Furthermore, I asked a research center (Y51) that specializes in tuning car racing to make me softer S30Z rally springs and shock absorbers, and sent them by air freight to a Datsun dealer in the Netherlands.

Mr. Kamata instructed the local staff to assemble the parts, but the evaluation was as expected: “OK” for high-speed stability, but the shocks on cobblestones were too strong, so it was a no-go.
Taking this evaluation into account, we sent three copies each of the following parts: loose shock absorbers, springs and stabilizers, and asked Mr. Kamata to assemble them according to his opinion of a good specification.

It seems that it was difficult to adapt them to all road conditions, but we also assembled the same suspension that Mr. Kamata had assembled in the Netherlands, and we worked together to solve the problems by assembling a crosswind generator on the Oppama test course.　

Since we were focusing on the high-speed stability of the NG items, we tested the specs recommended by Mr. Kamata on the Oppama test course, and they were well received there as well. The specs we planned to request from the local tuning factory were evaluated as better than the final specs, and we were able to get an excellent evaluation from the local dealer (Datsun Nederland) in the end.

When the European version of the S30Z was developed, there was not only an exchange of ideas between different models, which had not happened before, but also collaboration with the research center (Y51), which had not been involved in the development of production vehicles up to that point. I think it's fair to say that the car was created by the Nissan Motor Company as a whole.

More than 50 years have passed since then, but no other car has been developed by the entire company, and I think the S30Z is the greatest treasure Nissan Motor has created.

I was involved in the development of the S30Z, and it was a constant struggle, but I also experienced the satisfaction of solving the problems, and I think that in my life I can be proud of being able to send the S30Z out into the world.

The final Euro-spec front spoiler

We were trying to reduce the drag with adding a front spoiler. It was not really oriented to development of Euro versions.

We tried various height from the ground. A bigger spoiler gets much better results in reducing the front lift but worse in drag.
Today, you see the Euro front spoiler was originally a bit wider in vertical, which means a bit closer to the ground (approximately 10mm.)
But what made the Euro front spoiler as it has the size today?
It because of the tire stopper height at the parking lot in Japan. Late 1960s Japanese roads still yet to be unsophisticated, especially in countryside. Several highways had begun to operate, but not so popular for many people.
Then the tire stoppers were not always the same height, they varied a lot.
So we took advantage of avoiding scratches. Maybe we checked how the tire stopper in Europe, but I can’t remember that.
I don’t know why the fron spoiler, it wasn’t available in Japanese market.

Creating a new car

Many people think that a car is created by a designer coming up with the shape, creating the design for each part, making a prototype with each part, and when it is assembled, checking the performance in a test, and then it is finished.

Normally, we would take a randomly selected car off the assembly line every two months to check the quality of the production line. After the inspection, the car was not sold to the public, but purchased and registered by Nissan.
The car was then assigned to each department as a “commuter vehicle”.
One day, a Z432-R was delivered to our department. This was unusual, because normally cars like sedans or small station wagons were delivered.
To be honest, I didn't like the car at all. It had no radio, heater or blower. I was not happy commuting between the Tsurumi Design Center and the Oppama test track, or sometimes other facilities such as the Nissan Ginza headquarters.
And of course, it was so rare on the road that I was stopped and checked by the police quite often. I guess the police officers just wanted to see the Z432-R out of curiosity.

When the S30Z was announced, there were quite a few people in the development department who loved the SR311, and there was a debate about which was faster, the S30Z or the SR311, on the Hakone Turnpike (a toll road for tourists) that Nissan uses to check power performance and brake performance.
And so we decided to have a race! We got permission for a “power performance test” and went to the Hakone Turnpike in three cars: the SR311, the 432Z and the 2LZ.
Mr. T, who owns his own car and participates in gymkhana events, drove the SR311, Mr. K, who is said to be the most careful driver in the experimental department, drove the 432Z, and I drove the 2LZ. The results were that the 432Z was the fastest on both the up and down slopes, the L2Z was a little faster than the SR311 on the up slope, and the L2Z was about a minute faster on the down slope.
The results were the same even when people switched cars. The result of the SR311 was probably due to the performance of the Solex?
It had good response and torque, but with a rigid differential, it had poor ground contact and slid outwards in corners, so it was a shame that I couldn't step on the accelerator. In comparison, the S30Z seemed to drive quietly overall, and although it rolled in corners, it doesn't slip outwards and the tires grip the ground, so it ends up being faster. I was reminded once again of the good suspension of the S30Z.

This is just my personal opinion, but if someone were to ask me, “Did you build the S30Z?” my answer would be “No”.

From the prototype stage to the completion and launch of the S30Z, I was certainly involved in checking the operability and visibility of the driver's seat area before the prototype arrived, and then checking the drivability and driving performance as soon as the prototype arrived.

Just before completion, we conducted aerodynamic experiments in a wind tunnel and, in collaboration with the heat resistance group, we solved several problems and achieved our target values, such as improving drag and stability at high speeds. However, we were able to achieve all of this with the help of our colleagues in the various fields.

When asked “Who built the S30Z?”, there are other people besides our sports car team who helped with each step of the development, and the car was only made through the efforts of everyone.

I was assigned to the sports car team, and at that point we still had three months before the prototype was due. Normally, the development of a new car is carried out by the staff in charge of that particular model, and they work to make it as good as other models, but in the development of the S30Z, there were one and departments, and I happened to be free at the time, so I received technical guidance from the leading staff on interior operability, driving performance, and aerodynamics (high-speed stability).

As a result, I was in charge of the driving tests and development from the start of the development to its completion.
I didn't build the S30Z, but I think I was involved in the development for the longest time.

This is a small side note, but I got married just as I was busy with the S30Z crosswind countermeasures. At the time, I was working six days a week, and when I had to work on Sundays, I slept in the company restroom because it meant 13 consecutive days of work. When I came home after two weeks, I found a note from my new wife saying, "I'm going home to my parents." and I had to hurry to pick her up at her parents".

Thanks to my wife, after several days, she returned to our home. That is also a nostalgic memory now.

The development of S30Z was really fun every day.