Earlier this month, Toyota wrapped up this year’s World Endurance Championship manufacturers’ crown with another convincing display on home turf at Fuji. It marks the fifth time in a row, and sixth in total, it has come away with the silverware, including the occasions when a teams’ title was awarded instead of a manufacturers’.
Pending the outcome of the final round of the season in Bahrain, Toyota could feasibly come away with a clean sweep of wins barring the Le Mans 24 Hours, where a contentious pre-event Balance of Performance change handed the initiative to Ferrari.
Toyota has come a long way since the beginning of its current WEC programme, which began in 2012 with the TS030 HYBRID LMP1 - which was followed up by the TS040 and TS050, and then in 2021 by the GR010 HYBRID built to Le Mans Hypercar rules.
But while its rise from underdog against the likes of Porsche and Audi to the dominant force fans know today is well documented, less well known is how a privateer Japanese constructor that was almost ever-present during Toyota’s top-flight absence at Le Mans after 1999 contributed to getting the marque’s LMP1 project off the ground.
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In fact, so close were the links between Toyota and Dome towards the end of this period that the latter’s short-lived but fondly-remembered S102 LMP1 car of 2008 can be described as the “elder sister” of the TS030 HYBRID according to its creator, Hiroshi Yuchi. And for a period of time, Dome was in line to mastermind Toyota’s long-awaited return to La Sarthe.
“Toyota was behind the creation of the S102, as was revealed in Japanese media last year,” Yuchi tells Motorsport.com. “We knew the performance of the Judd engine and the aerodynamics, so it was a good performance benchmark for the development [of the TS030 HYBRID].
“Then we were working on a test car in 2009 and 2010, but when Toyota decided to stop Formula 1, the entire project and all the data was transferred to TMG (now Toyota Gazoo Racing Europe) in Cologne at the end of 2010. After F1, they had no project in Cologne.”
Toyota working with Dome was nothing new. Back in the '80s, Minoru Hayashi’s company had helped Toyota develop its early Group C efforts, and designed all of its Le Mans racers up until the end of the 1980s. After that, Dome shifted its focus to single-seaters, entering Japanese Formula 3000 (now Super Formula) with its own chassis in 1991.
Three years later, Dome won the Japanese F3000 title with Marco Apicella and then started making plans to enter Formula 1 with its own chassis, which began testing with Mugen engines in 1996. Towards the end of the decade, when it was becoming painfully clear that his F1 dream would remain exactly that, Hayashi shifted his attention to trying to conquer Le Mans.
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Dome’s LMP900 project was given the go-ahead in late 1999, and its first step was to acquire the BMW V12 LM that Team Goh had raced at Le Mans that year and totally revamp its aerodynamics. The modified car never raced, but the lessons learned were then applied when Dome started designing the S101, which would make its debut in 2001.
"At one stage, [Lammers] was P1. Then the Audis upped their pace… but watching Tom Kristensen through the final part of the track, you could tell he was having to push to match the time set by the Dome" Hiroshi Yuchi
Two examples of the S101 would race at Le Mans in the first year, with one going to John Nielsen’s Den Bla Avis outfit and the other to Jan Lammers and his Racing For Holland project. Although the Judd V10-powered car was unable to truly threaten Audi, it was quick enough to push the German marque over a single lap, as Yuchi fondly remembers.
“Qualifying was so exciting,” recalls Yuchi, an engineer on the S101 project having first joined Dome in 1997. “At one stage, [Lammers] was P1. Then the Audis upped their pace… but watching Tom Kristensen through the final part of the track, you could tell he was having to push to match the time set by the Dome. That’s a nice memory.”
Neither Dome would see the chequered flag in what was a wet and wild race, both succumbing to electrical issues. But in the absence of a budget to do proper endurance testing, one-lap pace would remain the calling card of the S101 throughout its life.
“Mr Hayashi always said pole position was the target, because to establish good reliability requires far more budget than we had,” Yuchi admits. “We would have had to have done a lot of endurance testing. He told us, we can’t guarantee reliability for 24 hours, so try and do the quickest lap in qualifying. Some people would say this is not the right attitude for endurance racing, but we were operating on a tiny fraction of the budget of Audi.”
In 2002, Racing for Holland scored the S101’s first Le Mans finish in eighth place. But Yuchi’s abiding memory of that year’s race again comes from qualifying, where Lammers was stripped of his best time having topped the opening qualifying session.
“Suddenly, many scrutineers came to the garage and started checking everything - they thought we shouldn’t be the quickest,” says Yuchi. “Then they checked the fuel. At the time, the FIA [Sportscar] championship used Shell fuel and Le Mans used Elf. It was a mistake by the team, but some remnants of the Shell fuel remained in the fuel cell.”
The S101 would achieve its best overall finish of sixth in 2003 as Racing for Holland expanded to a two-car effort. But the next season, Lammers’ squad lost its Michelin tyre deal, which affected its competitiveness. Even on Michelins, the S101 struggled to switch on its front tyres designed primarily for Audi and Bentley, meaning it could never quite replicate its qualifying pace on harder compounds in the race.
In 2005, Dome unveiled a revised version of the car known as the S101Hb - designed as a ‘hybrid’ between the new LMP1 and previous LMP900 rules - and entered what amounted to a factory team to run it, under the ‘Jim Gainer International’ banner. It would be driven by Seiji Ara, a Le Mans winner the previous year with the Team Goh Audi effort, and compatriots Katsutomo Kaneishi and Ryo Michigami, both making their second starts.
“We had a new floor with a big diffuser, and the aero was totally different,” says Yuchi of the Hb. “Now a lot of downforce came from the floor and it was easy to lose this under braking. That made the car harder to set up.
“The car only had one race before Le Mans at Spa, but it was changeable weather. Then we had a private test at Paul Ricard, we found a better set-up and we set a lap record. We didn’t have enough time to set the car up properly for Le Mans, but the project was only decided after Le Mans the previous year.”
The distinctive polka dot-liveried S101Hb qualified fourth, only just behind the quickest of the Audi R8s (albeit a few seconds off the pace of the Pescarolo C60s that swept the front row). Come the race itself, despite some setbacks, the Dome remained in the fight for a podium place until the early hours of the morning, when a terminal oil leak ended its charge. The same year, Toyota started making plans to return to Le Mans with hybrid power, and, impressed by the S101Hb’s performance, reached out to its former partners at Dome.
“We started some development work on the hybrid systems around this time,” Yuchi recalls. “We knew the performance of the S101, and we could see the difference between it and the Audi in the same race, which was important for Toyota to collect data. The S101 was a good benchmark in this respect. Simulation technology was improving at this time, so we could work out how much more power and aerodynamic performance we needed to match Audi.”
Dome handed the S101Hb over to Racing for Holland to campaign in 2006, and in 2007 it unveiled a further evolution of the car, the S101.5, which fully complied with the latest LMP1 regulations (even if it was just the upper part of the old car attached to a new chassis). This car would then form the basis of a test mule for Toyota’s hybrid systems that ran in the latter part of 2008 across a variety of tracks in Japan, without being noticed by local media.
By this point, Toyota had already entered the Tokachi 24 Hours (part of the Super Taikyu schedule until it was discontinued after 2008) twice with the help of Super GT squad SARD, marking the brand’s first official forays into hybrid racing. After turning up with a production-based Lexus GS450h in 2006, the next year Toyota fitted a hybrid system to a Supra GT500 car, which won the race outright by a massive 19 laps.
While the S102 was much quicker than its predecessor, and was again run by Dome as a factory effort, the game had moved on hugely in the last few years with the diesels
This was a busy period for Dome, which after the 2007 running of Le Mans had made the decision to produce an entirely new model, the S102, with the budgetary assistance of Toyota. Unlike the S101 and its variants, it was a closed-top car, but it was powered by the same 5.5-litre Judd V10 that was installed in the Racing for Holland-run S101.5 for 2007. But by now the ‘diesel wars’ were in full swing with Audi returning as a factory effort in 2006 with the R10 TDI, and Peugeot joining the fray in 2007 with the 908 HDi FAP.
Yuchi, who was responsible for the design of the S102, recalls: “We were limited on the powertrain side, but one benefit for us was that the diesel engines were so big and so Audi and Peugeot were limited in terms of weight distribution. We tried to put the engine in the middle of the car. The engine is actually installed partly inside the roll hoop section of the chassis, because the Judd engine was very narrow. Audi and Peugeot could not do this.
“The S102 had really good weight distribution, around 48:52. Audi was said to be a bit less than 45:55. We worked the front tyres really well and we had a good aero balance.”
While the S102 was much quicker than its predecessor, and was again run by Dome as a factory effort, the game had moved on hugely in the last few years with the diesels. Daisuke Ito set the car’s best lap in qualifying of 3m26.928s, which would have been enough for pole even in 2006, but such was the rapid pace of development that it was more than eight seconds away from the benchmark time set by Peugeot driver Stephane Sarrazin.
Still, Ito’s time was second-best of the non-diesels, behind Stefan Mucke in the Charouz Lola-Aston Martin, whose road car-derived engine was more potent that the Dome’s Judd unit. The Japanese marque also had the disadvantage of a driver line-up made up entirely of rookies, with Ito joined in the cockpit by Yuji Tachikawa and Tatsuya Kataoka - all Toyota GT500 drivers at the time.
“Even at this time, people started suspecting that Toyota was behind the project,” admits Yuchi. “I think with more experienced drivers, we could have been two seconds a lap faster. But the diesels were impossible to match.”
Despite those disadvantages, the Dome remained in the mix for unofficial ‘petrol class’ honours until just before midnight, when an oil pressure problem put the S102 in the garage for just over an hour. Further time was lost in the morning when Ito crashed approaching Indianapolis, but after lengthy repairs the car made it back on track and completed enough laps to be the last classified finisher, albeit 109 laps down on the winning Audi.
The global recession hit the Japanese car industry hard, so there was no money to bring back the S102 to Le Mans in 2009, despite the promise the car had shown. But the development programme to bring Toyota back to the French endurance classic continued, and in the summer and autumn of 2010 a new hybrid-powered test mule, believed to be based on the S102, began running.
By this time, the packaging of the power unit and hybrid systems were close to the final form used on the TS030 HYBRID. But Toyota had withdrawn from F1 and needed a new project for the 150 or so staff it retained at its Cologne base. TMG technical boss Pascal Vasselon admits he made regular visits to Japan at this time, and the project is thought to have been transferred fully to TMG at the end of 2010, although its intentions to return to Le Mans were not made official until October 2011.
Toyota’s TS030 HYBRID made its debut at Le Mans in 2012, sharing the track with an evolution of its spiritual predecessor known as the S102.5. Dome had struck a deal with Pescarolo to run the upgraded car, which was brought up to date with the latest LMP1 regulations with some aerodynamic updates, including the ‘shark fin’ engine cover that had become mandatory for LMP1 cars in the interim, larger front wheels and reworked front suspension. The previous Judd V10 made way for a 3.4-litre V8 from the same firm.
Yuchi takes up the story of how the S102.5 - the same chassis that had raced in 2008 - made its way back to La Sarthe, crediting the late Ricardo Divila for making it happen: “After Ricardo left Nissan [at the end of 2008] he often came back to Japan. He was working for Pescarolo at the time, and he always told me, the S102 should come back to Le Mans, it shouldn’t just sit in the lobby of the factory! But there was no budget.
“Ricardo talked with Pescarolo. Basically, we loaned the car to them for free and they paid all the running costs. Ricardo engineered the car. So it was thanks to him that the S102 came back to Le Mans.”
By now, Le Mans had moved on from the diesel wars to the beginning of the hybrid age, and the chances of a plucky constructor like Dome making an impact on a shoestring budget had become much more remote compared to a decade earlier.
"As a designer, that was a good time, like a golden age for the privateers - a bit like the early 1990s in F1, when a team like Leyton House could beat McLaren" Hiroshi Yuchi
“When we entered with the S101, this was a good time for privateers,” says Yuchi. “Now it’s a different world. Simulation technology is so much better now, and the calculation environment. This gives the engineers good predictions to make the car quicker. And if you don’t have this, it’s a huge disadvantage. You can translate resources into performance more easily now. The biggest teams can make really accurate developments.
“In 2001, Dome had its own wind tunnel and was capable of creating a competitive car. But now the budget needed for proper development is probably 10 or 20 times larger. As a designer, that was a good time, like a golden age for the privateers - a bit like the early 1990s in F1, when a team like Leyton House could beat McLaren. Now, no chance!”
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The legacy of Dome’s efforts to conquer Le Mans live on today with the hugely-successful Toyota WEC effort coming up to complete its 11th season. With the WEC about to experience a further boom in manufacturer participation in the next couple of seasons, it’s hard to see how any other company of such modest means could make such an impact on the world’s greatest endurance race any time in the near future.
