Unveiling their new engine in Tokyo should have been a significant moment for Honda to celebrate but behind the scenes, the storied grand prix team – as well as plenty of their Formula One rivals – are worried that a looming row over new engine regulations is threatening to overshadow the opening of the 2026 season.
So significant is the concern that it will be the key topic of discussion at a meeting between the FIA and the engine manufacturers set for Thursday before the first day of pre-season testing at Barcelon.
With a swathe of new engine and chassis rules coming into effect for the new season, how teams have adapted will be key to their performance, and perhaps allow some to steal a march that could render them uncatchable. Before a wheel has turned in anger, there are fears that Mercedes – who also provide engines to defending champions McLaren, Williams and Alpine – and Red Bull have gained a vital advantage.
The new generation of hybrid engines are likely to be the key to performance in 2026 and a dispute over how Mercedes, Red Bull, Honda – who are supplying Aston Martin – Ferrari and Audi have built their new units has been growing during the close season. There is mounting apprehension that Mercedes and Red Bull may have found a way to gain as much as between 0.3 and 0.4 seconds of a lap – a huge adavantage in F1 terms – over their competitors.
The technical advantage is centred around engine compression ratios, the difference between the maximum and minimum volume of the cylinder during the piston stroke. This season it is set at 16:1, measured at an ambient temperature when the car is at rest, but other manufacturers believe Mercedes and Red Bull have used materials that give them an edge. When running on a track, they take advantage of the thermal expansion of components to increase the compression ratio and an engine’s power but adhere to the rules when not running.
It is understood that Ferrari, Audi and Honda were so alarmed that they have written to the FIA and their concerns will now be aired at the meeting.
Red Bull are developing their own engines for the first time and their technical director, Ben Hodgkinson, who worked on Mercedes’ engines for 20 years, was bullish that all their works was entirely within the rules. If their rivals had missed a trick, it was their failing not Red Bull’s.
“I know what we’re doing. I’m confident that what we’re doing is legal,” he said. “Of course, we’ve taken it right to the very limit of what the regulations allow. I’d be surprised if everyone hasn’t done that.
“Any engineer that doesn’t understand about thermal expansion doesn’t belong in this sport, doesn’t deserve to be an engineer really. Understanding how materials behave in different temperatures, pressures, stresses, loads – that’s literally our job.”
That this was no small matter was emphasised by Honda as they launched their new engine. “Regulations do not have everything listed very clearly, bit by bit,” said their chief executive Toshihiro Mibe. “There is a lot of room for interpretation as well and this is a part of the race. So for the FIA, it’s up to them to decide on whether it’s good or bad. For Honda, we have a lot of different ideas, and we would like to discuss with the FIA to understand if our ideas are accepted or are not OK.”
Tetsushi Kakuda, Honda’s F1 project leader, went further in admitting their powerunit development was “not necessarily” going as expected. Koji Watanabe, president of Honda Racing Corporation, warned that the regulations were challenging and that “perhaps we will struggle”.
All of which will concern Aston Martin, and at Ferrari if they find themselves off the pace in what in the worse case scenario might almost be a two-tier field.
With Audi also building their power unit for the first time, they expressed their misgivings at their car launch on Tuesday night in Dresden. “If it’s real, it is certainly a significant gap in terms of performance and lap time, and that would make a difference when we come to competition,” said their chief operating officer, Mattia Binotto. The German team’s technical director, James Key, was already looking to the FIA. ““I think if it’s sort of bypassing the intent of the regulations, then it has to be in some way controlled,” he said. “We trust the FIA to do that.”
Crucially, it is unlikely there will be any change to the measurement procedures nor regulations in the short term. Although the FIA has stated that the regulations could at some point be revised. For the moment, however, if Mercedes, their customers and Red Bull really do enjoy a significant advantage in the early races, it might yet prove a gulf that cannot be bridged.
