Formula 1: The rules loophole that Red Bull, Liam Lawson could exploit in 2026 – Alex Powell
The start of the new Formula One season might still be more than a month away, but an exploitation of the sport’s new regulations could already give two engine manufacturers an upper hand – and Kiwi driver Liam Lawson could be one of the major beneficiaries.
With a drastic new set of regulations introduced for the 2026 season, both Red Bull and Mercedes have been accused of finding a loophole that effectively gives a leg-up over the rest of the field.
The loophole has seen both Red Bull and Mercedes exploit rule C5.4.3 in Formula One’s new regulations, geared towards the compression ratio of the new power unit’s cylinders.
That rule allows for a maximum 16:1 ratio, to be measured at what the regulations state as an “ambient temperature”.
However, rival power unit manufacturers Ferrari (who also provide engines for Cadillac and Haas), Honda (Aston Martin) and Audi are understood to have complained to the sport’s governing body, the FIA, that both Red Bull and Mercedes have been able to exploit thermal expansion.
In effect, that pushes the compression ratio from 16:1 towards 18:1 while their cars are in motion, allowed under the old regulations. It’s estimated that the Red Bull and Mercedes engines will allow cars an advantage of up to 0.4s per lap on their rivals.
The FIA has said it will review the situation, but has left the rules as they are for the time being.
Tellingly, though, as well as Red Bull making their own engines for the first time, in conjunction with American giants Ford, they’re also manufacturing power units for sister side Racing Bulls.
After holding off the challenge of Yuki Tsunoda to keep his seat in 2026, Lawson finds himself as the senior driver at Racing Bulls, and partners British-Swedish rookie Arvid Lindblad – the only fresh face on the grid.
Racing Bulls enter 2026 off the back of the team’s best season since entering the grid 20 years ago, when Red Bull purchased Minardi. With Lawson and Isack Hadjar, Racing Bulls finished sixth in the 2025 constructors championship with 92 points, just three clear of Aston Martin in seventh.
Hadjar has since been promoted to Red Bull’s senior ranks alongside four-time world champion Max Verstappen, but suffered a crash on the second day of pre-season shakedown testing in Barcelona.
Lawson, meanwhile, completed the first day of testing at the Circuit de Catalunya, and was the sixth-fastest of the nine drivers that took to the track. Williams will not be present at the shakedown, while Aston Martin’s new car will only be ready for the final two days at most.
Interestingly, Red Bull and Mercedes finished day one 2.030s and 1.493s faster than Alpine’s Franco Colapinto in third. Admittedly, Alpine – along with reigning champions McLaren – are also powered by Mercedes engines.
And even though Red Bull and Racing Bulls are not officially linked, there is much more of an incentive for collaboration between the two teams, with their shared power units, than between Mercedes and their affiliates.
As is usual with pre-season testing, though, performances should be taken with a grain of salt.
Even though Hadjar topped the timesheets on day one with a best lap of 1m 18.159s, that time was more than six seconds slower than the mark Oscar Piastri qualified with at the same track for the Spanish Grand Prix in 2025.
Hadjar’s testing time with Red Bull was also more than five seconds off the mark he set in last year’s Barcelona qualifying – in a Racing Bulls car.
Testing in Barcelona runs to the end of this week, before two final test runs in Bahrain next month.
In reality, though, it’s going to be hard to get a complete gauge of exactly where all the teams stand before qualifying for the Australian Grand Prix in Melbourne on March 7.
However, if the Red Bull engine in particular will bring advantages this season, being at Racing Bulls could prove a masterstroke for Lawson.
Alex Powell is a sports journalist for the NZ Herald. He has been a sports journalist since 2016.