Even as a young man in Japan, Nobuhiro "Monster" Tajima knew he wanted to compete in the annual Pikes Peak International Hill Climb. The race is the second oldest in the United States—2016 marks its 100th anniversary—and this track provides a rare challenge to driver and car in motorsport. Its 12.4 miles (19.9km) have more corners than the Nürburgring. The course rises 4,750 feet (1,440m) from the start line to the summit, finishing at 14,100 feet (4,300m). And forget mental images of mountain roads as nothing but switchbacks; there are plenty of straights and fast corners with nothing but a sharp drop off to one side.

And it's truly a hill climb. Racers set off one after another, and they only get one run. In fact, the first time they're able to drive the full 12.4 miles flat-out is during Sunday's race—practice and qualifying take place on shorter stretches of the route. For most of the race's history, the road to the top of the mountain was dirt. Paving started in 1998 following concerns about erosion, and the race has run on tarmac exclusively since 2012.

The unique setup means both car and driver must call upon different skills to set the fastest time of the day. Perfectly balanced drifts have given way to maximizing corner speed, and the tires are racing slicks with no tread blocks. But there's still that huge climb in altitude, finishing almost 3 miles (4.3km) up to where there's much less air to push down on wings or feed engines and radiators. On top of all that, the weather can give you four different seasons between the starting line and the summit, bringing with it all the associated consequences for track temperature and grip.

While it would take Tajima some years to make his way to Colorado, when he first raced the mountain in 1992 something obviously clicked. He won that year and has succeeded seven times since. In 2011, he was the first person to drop under 10 minutes. And in 2012, he made the switch to electric power. In its modern competitions, Pikes Peak has proven uniquely suited to racing electric vehicles. Such race cars don't suffer the loss of power at altitude that affects internal combustion engines, so you can be as fast on the run from Devil's Playground to the summit as you were down below the treeline. And with only one run allowed, battery recharging times don't create the same handicap as in other disciplines of motorsport. As quickly as he took to the summit itself, Tajima embraced this change, too.

The car

Elle Cayabyab Gitlin

Jonathan Gitlin

Elle Cayabyab Gitlin

Elle Cayabyab Gitlin

Jonathan Gitlin

Jonathan Gitlin

The car—called a Tajima Rimac E-Runner Concept_One—is an evolution of the EV that Tajima and Team APEV (Association for the Promotion of Electric Vehicles) have run since 2012. An earlier iteration of the car with two electric motors and 500kW/670hp allowed him to set new EV records at Pikes Peak in 2013 and 2014. Since 2015, Rimac Automobili has provided the car's 1.1MW (1,475hp) powertrain—four electric motors, one for each wheel—complete with software-controlled torque vectoring.

"Racing is really the best playground for development," Rimac vehicle dynamics engineer Kruno Hrvatinić told Ars. The Pikes Peak collaboration has evidently been an interesting one for the Croatian EV company. "After the first race [2015] we learned a lot. We took the torque vectoring system that we use in our supercars, and of course it didn't work as well as expected. We made a lot of improvements so that it's faster, more responsive. The thing we discovered when you give a car to an experienced race car driver like Tajima-san is if the system tries to smooth out the action too much and it responds sluggishly, the driver compensates faster than the system can. So we had to add a bit of predictive action here; we had to speed up the system and make it more direct, more predictable. So the system that we have in our supercar right now is a derivative of what we had in this car last year."

The four-wheel torque vectoring runs at 100Hz, Hrvatinić told me. "We give a torque command to each inverter 100 times a second, then take data from the accelerometer and gyroscope at the center of the car 100 times a second," he said. "The control loop then works at a 10ms sample time—it's a balance between how fast the car can respond and how fast we can control. There's no use sending the inverters a torque command they can't do anything with."

Implementing a traction control system for a car with no differential also requires the use of all four motors working in concert. "For a normal car, you generally turn off traction control at the track because you have a differential. When one wheel starts slipping you have to cut torque from the motor itself, and that makes you slower," Hrvatinić explained. "In our case, we can monitor the speed of each wheel and selectively remove torque from the wheel that is slipping. We control the slip ratio so that each wheel produces the maximum amount of force. Depending on whether you're in a corner or on a straightaway, that maximum amount of slip is different. And we estimate that using the gyroscope and accelerometer. It lets us know how fast the car is going, what amount of G it's pulling, and the amount of lateral side-slip."

Unfortunately, not all was entirely well with the E-Runner Concept_One's batteries. The first day of practice saw the new battery getting too hot, a problem that would dog the team for the rest of the event. Throughout practice and qualifying, the car was derated and running on a lower power setting, meaning the team focused on setup and handling rather than all-out speed. With only one run possible during Thursday's qualifying session, Tajima would have to settle for fifth fastest overall (third fastest EV).