On a warm October afternoon, dozens of the fastest and most advanced automobiles in the world are tearing up the Interlagos Race Track just south of São Paulo, Brazil. The high-pitched screams of the race cars are deafening as they run through practice laps on the twisty, hilly, 4.3-kilometer course, with its 15 turns and views of suburban high-rise apartment buildings in the distance.

With just two days to go before the Brazilian Formula 1 Grand Prix, the drivers are getting familiar with the course. And behind the scenes, but no less significant, the engineers are checking and tuning the countless vehicle technologies that will have to perform flawlessly over the 90 minutes of the race. The engineers are clustered in the pit area, and one of them, a blond Finn with a boyish face hardened into a studious glare, is watching real-time data flowing from one of the more than 80 sensors onboard his team's car to a bank of computers and monitors in the pit. He is Ossi Oikarinen, race engineer for one of the three cars in the Panasonic Toyota Racing team, based in Cologne, Germany.

Formula 1 is the apotheosis of automobile racing, with cars that are chock-full of technology and annual team budgets in the hundreds of millions of dollars. Engines in the single-seat cars are limited to 3 liters, but from that modest displacement (less than that of a typical passenger-car V6) the 10-cylinder engines generate an astounding 671 kilowatts (900 horsepower) at, say, 19 000 revolutions per minute.

On this particular day, 22 October, Oikarinen will make many important strategic decisions—what kind of tires to put on the cars, how much fuel to load into them for the time trials, and how many pit stops to make on race day.

During the break between two 1-hour practice sessions, mechanics take the cars apart, inspect and clean them, and put them back together. Other engineers check the fuel mixture and inspect the car's oil for signs of engine wear.

Meanwhile, Oikarinen, dressed in red Panasonic Toyota racing attire, is sitting down with driver Jarno Trulli, going over Trulli's observations about the car and the course and discussing the data that has gushed in while the car was on the course.

Oikarinen is aware that Trulli's safety, along with the hopes of his more than 600 teammates back in Germany, rides on his engineering judgment. He is quick to point out that he gets plenty of technical help. "There are four engineers who work with me, and I rely on their advice when making decisions on how to run the car," he says.

But tough decisions and a charged competitive environment aren't Oikarinen's only challenges. There's also the grueling, 8-month Grand Prix season, which started in March and consisted of 18 races in 18 cities and 17 countries on 5 continents.

On days leading up to a race, Oikarinen and his teammates work 12-hour days. Oikarinen takes the long hours and the constant travel in stride. Quiet, with round Harry Potter glasses, he appears unflappable. "It's the life and job I've chosen," he says with a shrug. "I'm happy with what I'm doing. Once I'm not, then I'll find something else."

Born in Lahti, Finland, a town of about 100 000 on the shores of Lake Vesijärvi, he got interested in all things technical as a small child, even though neither one of his parents had a technical bent (his father worked for the government and his mother was an accountant).

"I have loved cars and engines since I was small," he says, noting that he still keepsgo-carts and motorcycles in the garage of his home in Cologne, Germany. "Electrical engineering was a natural choice."

He never had specific plans to become a race engineer, although he always wanted to be involved with racing on some level. "Things just worked out that way," he says, "and I was lucky enough to get into it." And consistent with his easygoing personality, he adds "I've never really planned my life anyhow. So what comes, comes."

What came, after he graduated from university in 1995, was a job developing control logic for a furnace company in Germany. Then he moved to a company that made dampers for race cars. At the end of 1997, he got his first job as a Formula 1 engineer for Arrows, a team that no longer exists. He has been with Panasonic Toyota Racing since 2000.

Professional race EEs are a small group; in the very highest ranks of Formula 1 racing, there are only about 30 race engineers—roughly one for every car competing in the Grand Prix series.

To those aspiring engineers who would give their eyeteeth to do what Oikarinen does, he says: "Get your schooling done. But more importantly, get involved in racing clubs. Start with go-carts and work your way up." He adds, "There are many ways to do it. There's no proven rule."

The Brazilian race on 24 October ends with Oikarinen's car, driven by Trulli, coming in 12th among the 17 finishers, with an average speed of 204.389 kilometers per hour. It comes in roughly one lap behind the winner, Juan Pablo Montoya of the Williams-BMW team. With the season finally over, Oikarinen's plans are simple: "Two weeks vacation," he says.

And then it's off to Spain for winter testing on some of the racecourses there. Then back to Cologne to continue the never-ending cycle of design improvements that could someday make the Panasonic Toyota Racing team No. 1 in the world of Formula 1 racing.