Honda Is Doing The Unthinkable: Designing A New Engine In 2025

It feels like just five years ago, most people—including myself—suspected the world might never see a new gas engine for passenger cars again. Many automakers, preparing for the dawn of EV-only mandates from governments around the globe, had concrete plans to sunset their internal combustion powertrains for good and replace them with battery packs.

Of course, that hasn’t happened. A slowing demand for electric vehicles in the U.S.—one of the world’s hottest markets—due in part to the US government’s disappearing federal tax credit, means that automakers are taking a hard look at their 10-year plans and making some seismic changes, with most pivoting to hybrids.

Hybrids obviously still need ICEs to work, which means the gas engine has, for now, been spared. But the hunt for better emissions and fuel economy never stops, which means automakers won’t just keep using existing powertrains—they’ll improve what they have, and even come out with new engines.

Honda Is Leading The Charge

Earlier in the decade, Honda was among the earliest of the big Japanese automakers to set out on a path to mainstream EV production. It teamed up with General Motors to build cars on that company’s Ultium platform, and wanted to work with GM on cheaper co-developed architectures for the near future. Last year, it even revealed plans to develop an innovative solid-state battery.

Seeing as how automakers are losing any real incentive to build more EVs, Honda can’t put all of its eggs in that basket. Instead, it’s diversifying and expanding into the enlarging hybrid market. It said as much in a product announcement published earlier today:

As market demand for [hybrid-electric vehicle] models continues to grow, Honda positions its HEV models, especially the next-generation models scheduled to go on sale in 2027 and beyond, as a core group of products which will play key role during the transitional period leading up to the full-fledged popularization of HEVs.

Especially in the North American market, which will be the main market for HEV models, there will continue to be solid demand for large-size HEVs.

Honda announced plans to design a new hybrid powertrain to replace the aging gas-only 3.5-liter V6 found in the current Odyssey, Passport, Pilot, and Ridgeline back in May. Today, the company finally released more details. While I expected Honda to downsize to a four-cylinder engine, it didn’t. Instead, we’re getting a new V6 to power the system. That’s right, a new V6 in the year of our lord, 2025. Incredible.

But Why, Honda? Why?

Just how “new” is this V6? Honda is pretty light on the details, saying only that it’s “newly developed” in its release, and claiming a 30% bump in efficiency over the current gas V6, which achieves just 20 to 22 mpg combined, depending on the model it’s powering. Our man Sam Abuelsamid was on the ground in Tokyo for all of this Honda news, and according to him, it’s just a heavily reworked version of the current motor. From his article:

It’s essentially the same latest-generation dual-overhead cam 3.5-liter V6 found on the current Pilot and Passport, but it will be running on an Atkinson cycle (late intake valve closing) rather than the Otto cycle used for the current production engine. That means it will be significantly more efficient but have less torque and probably less than the current 285 hp, although the electric motors will more than make up for that.

The question remains: Why not downsize? Toyota’s moved in the direction of four-cylinders for the vehicles in this segment, with cars like the 4Runner and its iForce Max powertrain making a healthy 326 horsepower and 465 lb-ft of torque. In this case, it seems like Honda simply wants more towing and performance capability than a four-cylinder can provide. From its announcement:

Honda is developing a next-generation hybrid system featuring powerful driving performance and high towing capacity, as well as outstanding environmental performance, befitting large-size HEVs in the D-segment and larger[.]

[…]

Aiming to deliver a powerful yet high-quality driving experience befitting the large-size HEV segment, Honda will strive to improve the full-throttle acceleration performance of the finished vehicle by more than 10% compared to the ICE models currently being sold in the same segment by increasing the efficiency of the engine and each drive unit and by utilizing the battery assist.

That battery assist will come courtesy of up to three electric motors. The first two will be located up front next to the motor, one acting as a generator attached to the engine to feed power to the battery, and another to send power to the front wheels. Honda’s system retains the ability to connect the engine directly to the tires, too, when needed (see the graphic above). The third motor will be located at the back of the car, to spin the rear wheels—a first for Honda. The details are fascinating, so if you want to learn more, please read Sam’s piece.

Honda has yet to release any sort of power or fuel economy figures for this new V6 hybrid powertrain, but says the system is scheduled to go on sale in 2027. That makes sense; the current V6 and the platform it resides on are many years old at this point, with cars like the Ridgeline and Odyssey in desperate need of an update. So it won’t be long until the world sees exactly what the company has in store.

Top graphic images: Honda