Al Unser Jr. leading Emerson Fittipaldi in 1994 Indy 500.

INDYCAR’s new hybrid power unit, a first-of-its-kind collaboration of the Indianapolis-based sanctioning body, Honda and Chevrolet, makes its debut in next week’s Honda Indy 200 at Mid-Ohio presented by the 2025 Honda Civic Hybrid at the Mid-Ohio Sports Car Course. It’s the latest in a long line of powerplant technologies brought to the sport.

From stock block engines to turbochargers to electronic fuel injection systems, INDYCAR has welcomed interesting technologies over the years. For example, the first use of fuel injection at Indianapolis Motor Speedway was in 1949.

For the 1963 Indianapolis 500, Ford developed a V8 based on the Fairlane V8 that Jim Clark used to finish second to Parnelli Jones. The next year, Ford designed a double-overhead-cam version with four valves per cylinder. The unusual appearance was unlike anything ever seen at Indianapolis Motor Speedway. Ford won the “500” with Clark in 1965, Graham Hill in 1966 and A.J. Foyt in 1967.

Clark’s win came in the first year of the sport using pure methanol, a key safety initiative.

The car Andy Granatelli brought to the Speedway in 1967 featured a Pratt & Whitney gas turbine engine. It made a spectacular debut, with Jones leading 171 of the 200 laps before transmission failure ended the winning bid four laps short. The car was crashed by Joe Leonard in Turn 4 during qualifications for the next year’s race, and the damage was not fixed, ending the car’s career. The engine didn’t translate well to automobiles, but it became one of the most popular turboprop aircraft engines in history.

By 1968, Offenhauser was back with effective use of turbochargers, and Bobby Unser went to Victory Lane at the Speedway. That set up an interesting stretch of competition between the engine manufacturers over the next decade, with Ford winning the 1969 “500” with Mario Andretti using a destroked Indy V8.

Smokey Yunick was involved in many creative initiatives, including the 207-cubic inch twin-turbocharged engine built for the 1973 “500.” Rookie Jerry Karl drove the year-old Eagle that finished 26th due to turbo problems. Still, the engine design was awarded the prestigious Louis Schwitzer Award for innovation and engineering excellence at Indy. Roman Slobodynski’s laydown Offy engine similarly received the award in 1978.

Cosworth’s next-generation technology began its domination with Rick Mears’ Indy victory in 1979. Cosworth won the “500” nine consecutive years before Mears produced the first of six consecutive Indy wins for the Ilmor-Chevrolet V8 engine in 1988. That year, Chevrolet-powered cars swept the first five starting positions and the top three finishing positions. Mario Ilien had debuted the engine two years earlier.

Most of the Indy engines of the 1980s and 1990s were overhead cam designs, but Brayton Engineering developed a stock block Buick V6 engine that had formidable horsepower but was largely reliable. Pancho Carter won the pole with one in 1985 but he dropped out six laps into the race with an oil pump issue. Scott Brayton’s engine lasted only 19 laps.

In 1991, a USAC rule change allowed a stock block pushrod engine of 208 cubic inches. In preparation for the 1994 “500,” Team Penske developed its version of the Brayton engine. The Mercedes-badged pushrod V8 -- designed by Ilien -- dominated the race with Emerson Fittipaldi and winner Al Unser Jr. combining to lead all but seven laps. Shown above is Unser leading Fittipaldi early in the race.

The Oldsmobile Aurora engine that debuted in 1997 won five consecutive “500s,” and Honda won the Schwitzer Award in 2004 for its engine it debuted at Indy. Buddy Rice won that year’s “500” and Tony Kanaan dominated the series.

In the past two years, Shell’s 100% Renewable Race Fuel and Xtrac’s Electric Servo Actuator, a new gear change system for faster-shifting and more efficient transmissions, have been important innovations for the sport.