The Japanese series announced last year plans to switch to a second-generation biomass fuel supplied by German firm Haltermann Carless for the 2023 campaign as part of a drive to reduce carbon emissions.
Teams sampled the fuel in a post-season test at Motegi after the final round of the season last year, but difficulties in supply mean most manufacturer testing over the winter has been conducted with regular gasoline.
Engine development is likely to be a major focus for GT500 marques Honda, Toyota and Nissan this year with aerodynamic development frozen for the upcoming season.
Impul Nissan driver Baguette believes that the shift to carbon-neutral fuel (CNF) has the potential to shake up the competitive order.
"The aero is frozen, but there’s a big change coming with the CNF," Baguette told Autosport. "We have to see how the different manufacturers adapt to that.
"It hasn't been used so much over the winter, so we have no idea yet who seems to be more impacted.
"The tyres will be a factor like always, but I think the key factor will be the engine and adapting to CNF."
Manufacturer testing has so far been dominated by Honda, which has topped every one of the five days of running that has taken place this year with multiple GT500 marques in attendance.
But TOM'S Toyota driver Ritomo Miyata says the impending switch to CNF means that the real picture won't become clear until official pre-season testing kicks off next month.
Miyata told Autosport: "So far I didn’t really feel an improvement with the [Toyota] engine, and Honda has always been the fastest in the timesheets, but we don’t know what will happen when we start using this CNF.
"I think all three manufacturers were using normal fuel [in the most recent test at Okayama]. But we need to know the character of the CNF and how it will impact the engine’s driveability.
"It could be quite a big change from normal fuel, so we need to learn how to use this properly."
New biofuel deal for Supercars
Meanwhile, the Australian Supercars championship will switch to a new biofuel blend as part of a new deal with supplier BP. The series has long used an ethanol blend as its control fuel with the previous-generation cars powered by a BP-branded E85 mix.
The switch to the new Gen3 platform has now prompted the development of a new blend known as E75 which contains more than 80% second generation fuel components. The expectation of the new blend is that it will produce less carbon than its predecessor while also being more efficient, meaning less fuel use across a race distance.
Its introduction to Supercars comes as part of an extension of BP's deal as the control fuel supplier, with the new blend to debut at the season-opening Newcastle 500 early next month.
Supercars CEO Shane Howard hailed the introduction of the new fuel as an important milestone for the category.
"Supercars has always been committed to being at the forefront of innovation and sustainability, and this transition to a lower carbon fuel product is the next step in our journey towards a more sustainable future," he said.
"This change to a lower carbon fuel product represents a major milestone for Supercars and our fans.
"We're excited to be leading the way in sustainable racing and look forward to the positive impact this will have for our sport."
