After spending seven years with Honda engines as his only point of reference for NTT IndyCar Series propulsion, Alexander Rossi’s move to Arrow McLaren came with a switch to Team Chevy’s 2.2-liter twin-turbo V6 powerplant and a need to learn how to get the most from the 750hp mill.

Sophomore driver Kyle Kirkwood went in the opposite direction, trading his A.J. Foyt Racing Chevy for Rossi’s former Andretti seat where, after a rookie season spent inside the Bowtie’s world, he’s getting to know to extract the most from Honda’s twin-turbo V6.

Between the two Americans, the process of learning about the different power delivery characteristics, tuning preferences, and plenty of other small details between Team Chevy/Ilmor Engineering and Honda Performance Development has been an important part of their onboarding processes at Arrow McLaren and Andretti Autosport.

“I think I potentially underestimated the size of the differences a little bit,” Rossi told RACER. “Because they’re both 2.2-liter turbo V6s, it’s the same architecture, so how on earth could it be that much different? But it is it truly is. Driving a Honda for so long, and that being the only thing that I knew, you learn very quickly that Chevy and GM have very specific areas, even mundane sorts of things, where they’re highly focused.

There’s a large learning curve to switching engine manufacturers for a veteran like Rossi. Fresher faces, maybe not so much… Richard Dole/Lumen

“And I knew that they were going to be different, and there’s areas where it’s better, and there’s areas where it’s worse. It’s fascinating because ultimately, all these engines can be on pole and do the lap time. But it’s just it’s amazing how it comes from such different areas of the track.”

Rossi’s race engineer Craig Hampson has been impressed with how quickly his new driver has come to grips with Chevy’s championship-winning motor.

“The engine behaves differently than the engine that he drove for a long time, and then all the terminology around it is different,” Hampson said. “And the way that Chevrolet interacts with the driver and tries to tailor the engine to their needs is different than his former manufacturer approaches the subject, and all of that has meant there’s been a lot learning for him and getting used to it.

“And we only get a few days of testing before the first race; it’s not like you get all winter working with it to get familiar with it, so he hasn’t done extensive fuel saving with it or done tire saving. Nor has he turned it up for qualifying with the alternate tires, or interacted with the engine on really worn-out rear tires, so there’s a lot of stuff that he’ll experience for the first time. But he’s incredibly smart and I have no doubt he’ll pick everything up right away.”

For Kirkwood, who lacks the years of deep institutional knowledge Rossi gained as a factory Honda driver, the switch from Chevy/Ilmor to HPD has been less of an adjustment.

“I really think they’re very comparable after having a back-to-back using both engines,” he said. “Now that I’ve driven both, I don’t feel a massive difference. I think both manufacturers are at a point where they’ve maximized their engines. There’s a couple of pros and cons between both, which I’ll keep to myself.

“And I don’t think I’m saying anything people don’t already know, but both do a really good job of aiding their drivers with how the engines perform; how they pull power out in certain gears or at certain revs are similar, so there’s a lot that just works pretty seamlessly with the two engines. Maybe if I’d been with one company for a lot more years, it would be a bigger adjustment for me to go from one to the others. And there are definitely some differences, but it’s been a blast getting to work with Honda. I can come up with some random ideas, and they’ll take it and try to make it work. It’s a lot of fun.”