At Sunday's 99th running of the Indianapolis 500, half the engines circling the track at nearly 200 mph will have come from a small factory in the Santa Clarita hills.
That's where Honda engineers prepared for their showdown with Chevrolet, which supplies the other half of the engines for this weekend's contest.
The rivalry between manufacturers is a race within the race, for bragging rights and for the Engine Manufacturer Championship of the 16-race Verizon IndyCar Series. Both Honda and Chevrolet see important business benefits from investing millions of dollars in IndyCar racing annually.
Race fans tend to be consumers who influence other people's purchase decisions, making it important to get your name and automotive technology in front of enthusiasts, said Jim Campbell, Chevrolet vice president for performance vehicles and motor sports.
Former Indianapolis 500 champion Bobby Rahal — whose Rahal Letterman Lanigan Racing team is running two cars Sunday, with Honda engines — understands the business implications well. He also owns 16 auto dealerships from 12 brands, including Honda.
"I am a firm believer in 'win on Sunday, sell on Monday,'" he said.
On the track, the battle of the manufacturers isn't so simple as a showdown of American and Japanese engineers. Reflecting the truly globalized car market, the pedigree of these power plants is more complicated.
Both engines were built in America — but neither by American manufacturers.
Chevrolet hired out the work to Ilmor Engineering, a small British manufacturer of race car and marine engines. Ilmor did set up shop in Plymouth, Mich., however, a short drive from its overseers at Chevrolet. Honda designs and builds its engines in-house, but at an out-of-the-way factory in Southern California.
Because Honda and Chevrolet are the only two manufacturers on the circuit, the battle between them might be more fierce than their competition in new car showrooms, where each also fights dozens of auto brands.
The IndyCar series is the pinnacle of U.S. auto racing. The open-wheeled vehicles weigh just 1,600 pounds, and they're faster than the more conventional sports and stock cars.
All the cars are built from the same chassis. What differentiates the vehicles mechanically are the engines and aerodynamic structures — teams can choose from either the Honda or Chevrolet combo. Rules dictate that no matter the builder, the engines must be a 2.2-liter, twin turbocharged, direct-injected V-6 with 500 to 700 horsepower, depending on the tuning.
"The key to success is not to have engine problems. Just put gas in the car and go," said Art St. Cyr, president of Honda Performance Development, the racing arm of American Honda Motor Co.
Honda will have engines in 17 of the 33 cars running Sunday.
"This is far and away our most important race. It is racing in America, and winning is our No. 1 goal," said St. Cyr, who previously managed product development for the automaker.
Beyond marketing, manufacturers use racing as a test bed for finding new technologies that wind up later in passenger cars.
"What we learn on the race track does help us build better powertrains for the showroom," Campbell said.
Characteristics such as performance, durability and fuel economy are crucial for racing but just as important for the engines that go into work trucks and passenger cars, he said.
Honda developed direct injection systems from racing, for instance, before putting them in mass-produced cars, St. Cyr said.
IndyCar racing also is an important component of engineer training. The companies rotate engineers through stints on the circuit.
"It makes you think on your feet and do things on a deadline, because the race happens whether you are ready or not," St. Cyr said. "Those are key attributes that Honda wants in its engineers."
Both companies have deep ties to the Indianapolis 500.
The brand's co-founder, Louis Chevrolet, and his brothers Arthur and Gaston all competed in the early races. Gaston Chevrolet won in 1920.
More recently, Honda has dominated.
From 2006 through 2011, it was the only company making engines for the race, winning all by default. And it has done well since competitors jumped back in. Cars with its engines won again in 2012 and 2014.
Honda could use a win this year to extend its points lead over Chevrolet for the manufacturer's championship trophy. Through the first five races on the 16-event circuit, Honda has 441 points while Chevrolet has 336.
Still, teams with Chevrolet engines won four of the first five races and have the better starting positions at Sunday's race.
The only reason Honda is ahead is because Chevrolet had to repair the valve springs on 11 engines after the first IndyCar race in St. Petersburg, Fla., in March. That cost Chevy 220 points.
IndyCar rules dictate that each engine must last for 2,500 miles, and it can't have anything more than normal — for race cars — service and maintenance. The bad springs generated a 20-point deduction for each of the engines that required repair.
Chevrolet spotted the problem and decided it had to fix the engines because the valve springs were unlikely to survive the circuit.
"We felt it was the right thing to do," Campbell said. "We didn't want to have an issue on the track."
Honda and Chevrolet accrue points for reaching the engine mileage threshold, having a driver win a race using one of their engines and other milestones.
And there's double points for the Indianapolis 500.
Campbell thinks Chevrolet can catch Honda despite its early engine stumble.
"There are a lot of races to go," he said.
Honda begs to differ.
"We know our engine is competitive," St. Cyr said. "We have strong drivers, so we have a very good chance of winning Sunday."