At long last Toyota has revealed the full story of how they recreated their first race car, the 1951 Toyopet Racer. News of the car’s existence was only made public last year, and after 71 years lost to history no examples had survived. Toyota sought to build a replica from scratch, and though the car was primitive by today’s standards the project, even with all the manufacturing might behind one of the largest automakers in the world, proved much more difficult than it might seem at first.
History of the Toyopet Racer
Prior to the Toyopet Racer’s discovery, the oldest known Toyota race car was thought to be the 1957 Toyopet Crown that finished the 19-day, 10,500-mile Mobilgas Trial of Australia. It wasn’t until Hideo Matsumoto, a retired employee of Toyota’s Motorsports Division and the Toyota Automobile Museum, published a book title Prehistory of Toyota’s Motorsport Activities that the Toyopet Racer came to light.
Even Naoaki Nunogaki, the current director of the Toyota Automobile Museum, hadn’t heard of it. However, when Nunogaki, who was involved in the development of the Altezza, original Harrier/Lexus RX, and ist/Scion xA, learned of it from Matsumoto’s book he went to then-president Akio Toyoda to request approval to remake the race car.
Unsurprisingly, Toyoda approved immediately. Why wouldn’t the avid car nut and master driver want to honor his family’s legacy? It was Kiichiro Toyoda, his grandfather, who founded Toyota Motor Co. and it was his idea to build the company’s first race car. He believed that “We [at Toyota] must build a racing car and participate in races as soon as possible” to close the technology gap between Japan’s auto industry and that of Europe and the US.
This was no small feat. Back then, Japanese companies weren’t even allowed to build passenger cars without a permit from the General Headquarters of the Supreme Commander for the Allied Powers. At the same time, Japan was in a recession and labor strikes had swept the auto industry. Kiichiro Toyoda was forced to resign as Toyota’s president the same year the Toyopet Racer was announced. The Toyopet Racer remake project would kick off 70 years later, in May 2020.
Channeling the Spirits of the Original Makers
A request for volunteers was sent out across Toyota’s many departments. During his presidency Akio Toyoda realized that Toyota had grown so big that engineers were only trained in their particular area of expertise. Akio believed that even if these engineers were the best at what they did, they couldn’t make good cars without a holistic understanding of the entire machine.
The Toyopet Racer project operated under one guiding principle: that the work was to be done by hand, without reliance on modern technology. Executive Fellow Mitsuru Kawai, who joined Toyota in 1966, has been a strong advocate of monozukuri, a uniquely Japanese word with no English counterpart. Though it literally defined as “manufacturing”, in spirit it is closer to “craftsmanship” and “dedication to the pursuit of improvement”.
“Today’s carmaking that relies on machines is heading in the opposite direction of the principles of monozukuri,” Kawai said. He even launched an initiative within Toyota to “pass on defining skills” to young employees. In this vein, project leaders recruited young engineers and paired them with veterans. Fifteen volunteer engineers in their 20s and 30s were chosen from various departments and teamed up with oyaji (literally “old men”) who are experts in sheetmetal shaping, welding, and chassis design and evaluation. Even outside help from legendary Toyota restorer Minoru Ishikawa, known as “a walking encyclopedia of classic Toyotas”, was brought in.
Keiji Kojima, General Manager of Technical Development & Prototype Division, was another project leader. He oversees the creation of Toyota’s test mules and called the venture “unprecedented”. Normally when he’s asked to build prototype cars from plain steel sheets for testing purposes he’s given detailed blueprints. With the Toyopet Racer, documents pertaining to the mechanics of the car were next to zero.
“We would be creating something from scratch, which makes it incredibly difficult. Even so, it was a really interesting challenge. I was absolutely convinced that we could do it, because all the technicians in our division can make almost anything. They’re particularly skilled at bending and beating steel sheets to form shapes,” Kojima said. “However, what posed the biggest challenge was the engine. It’s difficult to create an engine from nothing.”
Engine and Transmission
As it happens, the Toyota Automobile Museum had and extra engine lying around. The Toyopet Racer was based on the Toyopet Model SD, introduced in 1949 to cater to the taxi market. As such, they shared the same engine, a side-valve 995cc inline-4 making just 27 horsepower.
Unfortunately, after disassembling the engine they found it needed a lot of work. Rust had crept into internals and eaten away at some of the bearing caps. The cylinder wall were scored. The team used old school methods of building the metal back up and honing it down to fix the rust-eaten parts, and reverse engineered gaskets from scratch.
Turns out, the engine was the easy part. The team also needed a transmission, which didn’t exist. So they set about reconstructing the 4-speed manual from 70-year-old design drawings of the Model SD’s gearbox. Unfortunately, the more they dug the more they realized that the blueprints were incomplete, with key sections lost to time.
That’s when the engineers brought in a Toyopet Model SG truck from the Toyota Automobile Museum. The SG was basically a truck version of the SD, so team members were able to study its transmission and cast new parts based on it. Even so, they modified some parts so they could work with off-the-shelf components like bearings and seals that are available today. Still, tolerances, clearances, and heat treatment for each part all had to be experimented with.
The most difficult part to make proved to be the transmission case, which required a sand cast. Here they took some liberties with traditional methods, which would’ve required a lot of prototyping trial and error. Instead, they used modern additive manufacturing technology to 3D-print the sand cast.
About three months into building a seven-decade-old gearbox from the ground up, the team discovered an original one that needed an overhaul. Nevertheless, they were far enough into the scratch-built one that they continued in tandem. Ultimately, they ended up with two, a new one and a restored one.
Chassis and Body
The Toyopet Racer was a crude machine, built atop the ladder frame of a Toyopet Model SB, a compact truck launched in 1947. There were no donor chassis, so Toyota had to essentially custom build one. In present day the rails of a ladder frames are formed in a 1000-ton press, but the team didn’t have the budget to create a mold for a one-off project.
Instead, they came up with a new technique called sequential shift bending. The novel method doesn’t require a mold, instead using 10-ton force to slowly bend the square pipes little by little, shifting the fulcrum a little bit each time, and using a solid metal bar inserted into the pipe to minimize wrinkling.
In the end, Toyota and Taiho Seiki, a manufacturing company they partnered with they partnered with for this part of the project, were able to apply for patents on this method. They believe it can be used to restore other classic cars or used to build limited-run vehicles.
Once the chassis was complete, the team built a skeleton frame atop it. Riveted to the cage would be the sheetmetal, which was hand-beaten with no filler putty used at all. It was an effort to use the techniques available to the original creators of the Toyopet Racer as much as possible. Toyota estimates that creating the body panels by hand took several thousand hours.
The Toyopet Racer doesn’t have much of a cabin. It does have a single seat for the driver, and that proved to be quite difficult to recreate. There was no documentation detailing the structure, size, or strength requirements for the original. So the team went to the Toyota Automobile Museum to study seats from other Toyotas built in the 1950s.
The found that back then seat frames used wood rather than metal. Instead of polyurethane padding they used coconut fiber with coil springs like an old sofa. Rather than bolting them into rails attached to the floorpan, the team was surprised to discover that old seats were simply slid in.
After studying brochures, ads, and magazine articles from the time, they went with a reddish-brown vinyl for the upholstery. To determine the shape of the seat, the interviewed the son of a Toyopet Racer driver and learned that his father simply had clung onto the large steering wheel located between his legs. With no power steering the drivers had to really wrestle the wheel, and by the end of the race they were so tired that they draped their arms over it and steered with body weight.
As for safety, there was nothing of the sort. The Toyopet Racer didn’t even have seat belts. Here, the team made a choice to deviate from the original and add belts for some modicum of protection for the driver. However, they made them detachable so that they wouldn’t be visible when the car was on display.
Suspension and Brakes
One of the most challenging pieces of the entire build was creating the over 4-foot-long I-beam front axle from nothing. They needed to create a mold, which in 2023 would be cut by computer-controlled machines. Staying true to techniques of the era, however, meant that the team had to create molds by chiseling into a solid block of metal, grinding the surface, and heat treating it to harden it.
Hand-chiseling the mold took up 10 percent of the entire project’s budget. It took 10 days of chiseling, removing between 4 and 5 kg of material (9 and 11 pounds) of material by hand. The engineers said that by the end of a day’s chiseling, their hands were so sore and numb that they couldn’t even pick up a bottle of soap to wash them with or raise their arms.
Next, they had to transform a block of steel into a hammer-forged beam roughly in the shape of the axle, with about 9 bends in it. This required heating the steel until it was glowing yellow and pounding it into shape, just like a medieval blacksmith. After tempering it for strength, it would be close enough in shape that they could place it into the mold chiseled out in the previous step. Molding would take place at Riken Forge, a partner that produces parts for Toyota’s heavy duty truck division Hino.
However, due to the primitive nature of the technique, the team had to create produce 10 hand-hammered bent beams to account for inconsistencies in the molding process. Several did not emerge from the mold fully formed and were discarded. After a long, painstaking journey, the team managed to create a front axle truly using nothing but the technology available in the early 1950s.
The rest of the suspension was just as mysterious. Again, no documentation about spring rates existed, so engineers had to estimate the values. The only footage of the car running had been filmed by NHK back in the day and it was just 20 seconds long. But by estimating the weight of the car, its center of gravity, and the condition of the road, they were able to get a rough idea of how the suspension was supposed to behave.
The material used to make the original leaf springs was no longer available, so the team once again made the difficult choice to deviate. They reproduced the springs with modern material, using a Land Cruiser’s leaf spring brackets as a reference. Another bit of interesting trivia is that the car had no front brakes to reduce weight, just rear drums for a dirt track. Recreating each one of these parts required creating a sand cast mold.
Even with all their hard work, when it came time to put all the piece together the team discovered that minor dimensional errors and slight deformities due to welding and other machining processes added up. Many corrections had to be made to get everything to fit together properly, providing new appreciation for how well manufactured new cars are today.
Records for the original Toyopet Racer indicated that its top speed was around 150 kph (93 mph), but the team estimated that the recreation could safely go about 100 kph (62 mph). Even so, there was a debate about whether it was necessary to stress-test the car after so much time and effort put into it, especially when it would ultimately be a static display.
Saki Miki, one of the project leads, said, “The people who created the Toyopet Racer at the time risked their lives to run the prototype and check its performance at its limits. Just like them we should be able to experience their thoughts and hardships by conducting performance tests at the limit.” It was decided that the team should definitely try to experience the car at speed. After a few shakedowns to suss out any remaining bugs, the team was able to drive the car at 100 kph at a test area on the Fuji Speedway grounds.
Back in 1951 Toyota knew that the Racer would never recoup its development costs by winning prize money in races. They built it to prove they could, and to get the public — as well as Toyota employees and customers — excited about cars and racing. In that same vein, when asked why they joined the project, the current team members all said some version of that it was for once-in-a-lifetime experience to work on something like this.
“Using the latest computer-controlled machine tools makes it easy to produce components quickly and accurately. But making something in that way wouldn’t bring us any closer to the ideas and difficulties experienced by people back then, who were making things mainly by hand,” project leader Keiji Kojima said. “What I wanted to do was to produce something using tools and methods from that time as much as possible, and in so doing rediscover what we have forgotten… and to pass down [those skills] to future generations.”
Images courtesy of Toyota.