Sunday’s 109th running of the Indy 500 saw Alex Palou win his fifth race of the season, a feat made even more impressive by the fact that the iconic Memorial Day weekend race was just the sixth race of the 2025 calendar. It was also the Spaniard’s first-ever oval win, further emphasizing the dreamy season Chip Ganassi’s new star is having so far. But amid all the Palou headlines, there’s an element that’s often less talked about: the Honda hybrid engine that made it possible.
When the bright-yellow, DHL-sponsored Honda crossed the yard of bricks ahead of its competitors Sunday, it wasn’t a coincidence. It was months, if not a full year of preparation by the No. 10 crew, but primarily, lots of practice during the month of May. Besides the usual challenges of running in a pack, drafting, turbulence, dealing with slower traffic, pit stops, and everything else that makes racing at 230 mph for nearly three hours a monumental challenge, there was a new layer to be concerned about this year. See, this year’s sold-out race was the first time the entire 33-car grid, Chevy or Honda, ran a spec hybrid system. And like everything else in racing, teams and drivers alike have had to learn how to use it to their advantage.
A Long Time Coming
It took IndyCar a long time to fulfill its promise to go hybrid—nearly five years, actually. Developmental delays, followed by manufacturing and shipping delays, resulted in a series of postponements that left everyone wondering if it would ever arrive. And when the pandemic of 2020 brought global chaos and the world came to a standstill, many wondered if it would even happen at all. But alas, nearly halfway through the 2024 season, IndyCar went racing with all-new hybrid systems at the Mid-Ohio Sports Car Course.
While this may be the first hybrid 500, it doesn’t mean teams went into the race completely blind. As Kelvin Fu, HRC US Vice President (and a real engineering wizard), explained to me the morning of the race, there’s been lots of model simulation and racing simulator work to optimize the system’s performance.
While HRC US—Honda’s racing branch in North America—provides plenty of support to its IndyCar teams, the ultimate application of the car’s drivetrain and other systems completely depends on the team. Furthermore, with both Honda and Chevy engines running the same hybrid and energy storage systems, the biggest challenge for the drivers is learning how to tame them and maximize their benefits, which is something they haven’t had much time to figure out at the Indianapolis Motor Speedway.
“In terms of preparation of the hybrid system, it all really works together as it’s integrated into the engine and chassis, etc,” Fu explained. “So it’s more simulation and situational preparation ahead of the 500. It’s a lot more trying to understand how the drivers can deploy the energy, as they’re already doing many things with the tools on their steering wheels, so that’s a challenge for them. Traditionally, drivers don’t want to be the first guy [at the front of the pack], but that may change. Drivers have to figure out moving around the pack and multiple strategies… [the new system brings] something different, and it forces teams and drivers to handle change.
“It’s going to be interesting [during the race], and we won’t know until it runs. Our assumption is that as you’re racing, the drivers who are better at harvesting and regenerating at the right time are going to slowly have an advantage as they go around. The ability to regen is going to be affected by where they are in the pack. If you are in the front, there’s less lifting [off the throttle], but as you fall back there’s [more lifting], and when you are lifting that’s when you are regenerating,” added Fu.
“Those guys might be able to build more energy, so they’ll have a better chance of passing. We’ll see how it goes, a lot of things can affect how the cars run—the cooler weather, downforce, etc. We think the hybrid system will have an effect on how effectively they can pass—the drivers and teams who can figure out the system better will move through the field easier.”
Overall race-pace speeds weren’t dramatically affected by the higher power of the hybrid—a combined 900 hp—as the car is about 100 pounds heavier than before. The system itself is housed alongside the engine and is about the size of a milk crate, making the packaging under the engine cover a bigger challenge than in previous years. And contrary to popular belief, it hasn’t made the engines more fuel efficient either. It’s 100% about power and performance.
Fu’s comments about the system favoring savvy drivers who do their homework resonated as the laps racked up during Sunday’s race. Palou, who started sixth, was never quite in the mix at the front for most of the race. In fact, it wasn’t until about lap 180 of 200 that he made his intentions extremely clear with a couple of aggressive passes on Chevy drivers Santino Ferrucci and Pato O’Ward. Prior to that, Palou was running steady within the top 10 or 12, managing his fuel strategy, making clean pit stops, and more importantly, avoiding chaos.
Over the course of 480-plus miles, Palou (along with everyone else) managed their energy harvesting and power output to up the pace when necessary, and go for crucial passes when needed. And little by little, the Spaniard positioned himself just right at the end of the race. He methodically did what he had to do to be within striking distance when it mattered most.
Honda would not comment on Palou’s specific management of the hybrid system during the race, but it curiously highlighted that during qualifying, data revealed that many drivers’ speeds during the fourth and final lap of Indy’s four-lap-average qualifying format were often the fastest. It’s usually the other way around as the tires begin to scrub, the engines begin to overheat from being turned to 11, and drivers begin to overthink and overcorrect. This year, however, drivers were harvesting during the first three and deploying that additional energy on the fourth lap. Surely, those same strategies were put into place on race day.
Back to the Front
Between 2004 and 2014, Chevy only managed to steal one Indy 500 win away from Honda. Since then, however, it’s been just about an even split between IndyCar’s two engine manufacturers. And after back-to-back Penske-Chevy wins at the hands of Josef Newgarden in 2023 and 2024 (one of those with a car of questionable legality), Honda’s sweep of the 2025 season so far highlights its engineering prowess—even when it comes to non-proprietary systems. And almost equally as important as winning is the fact that the hybrid components worked exactly as expected, and there were no hybrid failures or issues during the race in Honda-powered cars. To place first, you first have to finish the race.
When asked about any tweaks or further developments Honda would like to make to the hybrid system for next year, Fu highlighted that there have been some improvements since its debut, but so far, they’re pretty happy where things are at.
“Honda makes the super capacitor, and Chevy Ilmore makes the MGU, but it’s really IndyCar’s system,” said Fu. “It’s a combined effort between manufacturers that’s been good so far. We’ll propose improvements and other things, but there’s always a trade-off to making changes… as those things require costs, time, things need to be tested and validated, etc. Of course, Honda is always looking to make improvements, and this year we’ve already been able to increase the energy allowance.
“Overall, it’s a good system right now, and we don’t want to change it too much in the near future.”
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