Last month’s Indianapolis 500 marked the 100th running of “The Greatest Spectacle in Racing,” which originated at the Indianapolis Motor Speedway in 1911. (The math doesn’t work out for the intervening year span because the race wasn’t run during World War I and World War II.)
While the early races featured many cars that were essentially stripped-down production models – with wildly different specifications – it quickly became a contest between specially built racing machines. And in recent years, those machines have been primarily differentiated by what engine was powering them.
To even the odds, IndyCar race cars have long used engines that had to meet the same general specifications – though those specifications have changed quite a bit over the past two decades. In 1996, they were turbocharged V8s and V6s. The following year, they were all normally aspirated 4.0-liter V8s, which were shrunk to 3.5 liters in 2000 and to 3.0 liters in 2004. But since 2012, they’ve all been 2.2-liter twin-turbo V6s.
Today, only two manufacturers build engines used in the IndyCar Series: Chevrolet and Honda. The differences between them are primarily in the fine details (which neither manufacturer is particularly interested in divulging), but they generally put out between 575 and 675 horsepower, depending on the amount of boost allowed. (Less boost is allowed on oval tracks than on road courses to keep speeds within sane limits.)
Surprisingly, these engines have a dual-overhead-cam, four-valve-per-cylinder layout that isn’t much different than in modern production engines. But they use both port and direct (in-cylinder) fuel injection, dry-sump lubrication (to avoid oil starvation under the high forces the cars can generate under cornering, braking, and acceleration), run on E85 fuel (85 percent ethanol and 15 percent racing gas), and their smaller displacements and high-tech materials allow them to rev to more than 12,000 rpm!
In the first four years of the Chevrolet/Honda rivalry, Chevrolet has won all the Manufacturer Championships (by winning the most races), but the two companies evenly split the number of Indy 500 victories: Chevrolet-powered cars won in 2013 and 2015, Honda-powered ones in 2012 and 2014. This year, Honda broke the tie when rookie Alexander Rossi won the 100th running of the Indianapolis 500 after qualifying 11th at a speed of 228.473 mph (!), about 2-mph off the pace set by pole sitter James Hinchcliffe, who also drove a Honda-powered car.