By Mick Palmer

Hybrid is gone. The BTCC is back to using ‘Go’ juice and turbo boost as a propellant. The era of grabbing a chunk of electricity from a battery system to try and battle past a rival is consigned to history. The news that the tech has been retired has put a smile on the faces of many fans, and also those of many people in the paddock. Add in that the fuel next year will be 100% sustainable, then it’s happy days all around, because that brings some benefits that don’t immediately come to mind.

Using a button to try to pass someone is still on the menu. In the official BTCC press release revealing these changes for 2025 the championship points out that turbo boost alone – which made up a slab of the extra power previously deployed alongside the hybrid – will be the sole differentiation factor. Positive or negative, that will still be allocated in incremental steps to those at the front of the field on race weekends, via race results and championship positions. It’s a simple step – unplugging the hybrid and letting the cars run around 55kgs lighter than before – but that petrol? That is a dynamic shift.

Ignoring the political machinations behind the reasoning for moving to a 100% sustainable fuel, the practicalities seem to be a major challenge for any major motor racing championship making that move. In the WEC Peugeot engineers have spoken about sustainable fuel – thanks to its compounds – causing irregular spray patterns, and engine knock. These are problems to be overcome in a competitive environment, which adds pressure in that scenario to develop a competitive formula. In F1 fuel developers are, like they have always with petrol, finding they have to develop new blends on an almost daily basis in preparation for the 2026 ruleset for their engines. In the WRC, which like the BTCC is supplied by a single fuel provider, a slight engine temperature related issue was quickly solved, ensuring that no advantage or disadvantage was gained by any competitor. It seems unlikely, according to Un-Limited Motorsports, that these kinds of problems will hamper teams in the BTCC next season.

“They (Haltermann Carless) have already gone through the pain process of creating and developing it before we used it.”

With a single Cupra Leon occupied by Daryl DeLeon, the squad – under Team Manager Dave Tyson – raced the new fuel developed by Haltermann Carless across the final two rounds of 2024. The squad were happy with how the car performed. Tyson explained that the modifications needed to run the new fuel were minimal: “With sustainable fuel you have to change the ignition a little,” he pointed out, “but this fuel has been developed now to run in any car you want. You can go and put it your own car and it’ll run absolutely fine. They (Haltermann Carless) have already gone through the pain process of creating and developing it before we used it.”

To a cynic like me the hybrid concept that was developed for BTCC racing came across as a bit of greenwashing, and that feeling lingered all the way through the painful birthing process of the format until the end of last season. At the headline face value, the same thoughts rise with this new fuel, but the tone is different this time. The message from the championship is considered in that it approaches the new development as good for the credentials of the series, rather than publicly posturing for car manufacturers to come aboard thanks to some kind of halfway selling point. Apart from the sustainability angle in terms of pollutant output satisfying sustainability targets, it will in a small way quickly benefit the finances of BTCC teams.

“Consider the volume of fuel that will be used by the BTCC next season,” Tyson states. “We can make the cost come down. At the minute it’s about volume. So, the more volume you create, the quicker the price comes down and then becomes cheaper than higher octane fuel.”

The prediction that the fuel will very soon be cheaper than the high octane race fuel currently used in the BTCC as production capacity grows isn’t simple ruminating. According to the numbers from the last two rounds of last season, the team found that there was no difference in performance. In a country with a strong motorsport heritage and a huge club racing scene, even if sustainable fuels take time to pick up with the general public, the chance to use fuel with almost the same performance, but cheaper, will help to persuade racers to back the recently announced Motorsport UK plan to have all UK motor racing running on sustainable fuels by 2030.

Un-Limited were the perfect choice for the BTCC to trial this new product. The hybrid race trial with Andrew Jordan in a third Toyota at Silverstone in 2021 benefitted from running alongside two established cars running to the ballast rules. The fact that Un-Limited are a one driver, one car team meant that there would be no distractions in terms of back-to-back in real time with this venture, because that wasn’t needed. It was actually a step beyond proof of concept.

“Because we’re with M-Sport, which is the BTCC/TOCA engine supplier, and with us being a one car team, we were the obvious choice to go with.”

“We knew a couple of weeks before Silverstone – so that would have been around Donington,” Tyson says of when the project was pulled together. “We had a conversation with Sam Riches (TOCA Technical Director) and there were a few emails, then Sam chose us as the team to run it. Because we’re with M-Sport, which is the BTCC/TOCA engine supplier, and with us being a one car team, we were the obvious choice to go with. It was essentially a private test that we were doing on behalf of BTCC. They took their information back, but we had no issues with the car. We had no issues with running it at all.”

That M-Sport have experience with sustainable fuel in competition thanks to their WRC engine programme does help. Tyson, who himself has experience of using the product in projects away from BTCC, pointed out that the work at Silverstone and Brands Hatch wasn’t just ‘sucking and seeing’ as they ran the fuel in competition. There had been dyno work completed by M-Sport. “They knew where they were with it,” he explained. “So when it went in the car it was more of a real life scenario test than it was just a chuck it in and find out what it does.”

The other engine builders – Mountune, Ford; Swindon, Hyundai; Neil Brown, BMW and Toyota; will also have had engines on benches going through sweep tests and more with the fuel. Tyson believes that: “Everyone will just pour the fuel in, and find it runs a little bit differently, but they’ll soon work it out.”

“It does use a little bit more fuel. Probably about six percent.”

There were takeaways from the Silverstone and Donington races. Details that other teams will discover quickly in testing, if not from their engine partners prior to track running. Small things like weight and the rate at which the tank will empty. “It does use a little bit more fuel. Probably about six percent,” Tyson revealed. “But that will come down. If you look at where sustainable fuel companies were three years ago it was about 20% higher. So, we’re down to about six now, and I would imagine by the time we’re into it properly for next year, where they will still be advancing and developing, it’ll probably be down to two or three percent more. If you put 30 kilos in the tank – 3% of 30 kilos is nothing – it’s 900 grams – not even a kilo of fuel – you put in that amount extra already to be sure. We have to carry that in the tank at the end of the race anyway for any post-race checks. That extra doesn’t make a difference”

That weight is around that of a small watermelon, or for the like of myself, a couple of double quarter pounders and fries. It is negligible. The 55kgs pulled from the car will not be compensated for with the loss of the hybrid, so fuel weight will not factor at all, but the surprising bit of information is about car setup, at least in the case of Un-Limited.

“It won’t make a blind bit of difference,” I’m told of how much of the settings will change from data accrued last year for use next season. “It’s just that there’s no extra weight and we’re running on the sustainable fuel. There is no disadvantage to the teams in the BTCC doing what they’ve done.”

With there being no scramble to replace redundant data, the fuel performance being equal, and the price of the fuel coming down, what actual changes are to be made to the car? The new liquid is sold as a pure ‘drop in’ product. The equivalent commodity being used in the F1 supporting Porsche Supercup has required a number of small modifications to engine components, but for the BTCC what kind investment and adaptations will be needed? “Nothing,” Tyson replies.

“We cleaned the tank out and replaced all the seals, so we knew we were working with fresh ones, and used all the same original fuel lines. We had no issues.”

“We just flushed the car through before the Silverstone weekend. We cleaned the tank out and replaced all the seals, so we knew we were working with fresh ones, and used all the same original fuel lines. We had no issues. There’s a request for certain fuel lines to be used next season that work better with the chemicals in the new fuel, from what I understand. Once we get a technical spec through, we’ll know. But what do fuel lines cost? Pennies.”

The two big concentration points for 2025 will be weight re-distribution without the hybrid stuck beside the driver, and engine development, which is where the extra power for the overtaking boost will come via the turbo.

“They (the cars) are all going to be light because you’re taking that massive battery out,” Tyson considered for a moment. “Ultimately, they control it by boost. There is already a system in place to control the power and how the cars run and work. There’s a measurable system in place with boost, and if you overboost you know the penalty for it. So, it’s then about the teams, the engine builders and everybody trying to build the best engine they can. That allows them to run the boost in the manner that gives them the best power delivery.”

The turbo boost is set to deliver the same amount of power as the combined turbo and hybrid from this past season. While speaking to Craig Porley, engineer for Jake Hill, earlier in the season, he pointed out that BTCC machines are very, very much on a leash as far as how wound back they are. The figures he mentioned were under 400 bhp with the equivalent to 60 on tap. Next year, by that calculation, will mean that an actual 60 bhp from engine/turbo output needs to be ready at a split second, meaning that there has to be a decent margin above the 440-450 bhp when maxed out for a couple of seconds to ensure the longevity of the unit. This is something confirmed by Tyson.

“If you let them go, they’d be at 500 horsepower,” he affirmed. “If you let them go and just said ‘it’s open, go for what you like, just watch the boost,’ they still wouldn’t make an engine last long enough, so the teams with the biggest budget would be firing engines in every other weekend, and it becomes another £150,000 on your budget which would be just unsustainable.”

That last word, ‘unsustainable’ has been applied to many aspects of the BTCC over the last few seasons. Most of it related to cost. That is an area that has to change, but the overall move to create an environment that isn’t just environmentally sustainable is a large part of what is driving some of the changes we’re seeing in the category right now. There appears to be a unified uplift towards how the sport can move forward, and these changes appear to be a precursor to some of the cost reduction ideals that should be baked into the upcoming 2027 regulations.

While many people are happy about the change, one driver with knowledge of the change before the announcement was made public, told Touring Car Magazine that they’d: “Rather go back to the ballast, because it becomes a setup challenge.” They also said: “The problem with the boost is that it only works when its engaged. The rest of the time you’re not at a disadvantage with balance, braking into every corner, and tyres.”

One aspect of the hybrid removal though is cost. A member of another team told Touring Car Magazine: “Yeah, the cost of the hybrid has been removed, but you won’t see that drop the price of a drive next season in most cases. I think you’ll still see some drives become more expensive, and a lot just stay where it is. The teams need that money really. I think removing that pressure will allow for more stability, it’ll allow some teams a little margin, but I think removing the hybrid, which really only did a little bit for one season, will make entry more attractive for a new team. When you consider that hybrid, fuel, tyres and engines are the big external costs, losing one helps a lot, even though the tyre bill is bigger, and obviously the engine too, but you can’t race if you remove the other three.”

Over the last three seasons the hybrid has been a refined building project. Year one created racing that many fans found unsatisfactory, but it was needed to understand the technology and build in reliability. Year two was a proving ground, to build on lessons learned, and while the racing improved, the product was still short by a margin. From a spectator standpoint 2024 proved the best year for the hybrids, it seemed that the format was settled, but for 2025 we’re back to year zero. It would appear that there will not be a repeat of the shuffling forward and finding a way next season. It will be expected with the fuel being on song, and the engine output and boost at a similar level, that the BTCC, with yet to be announced changes to deployment increments, is on a path that will allow the racing to continue without having to justify the use of fossil fuels to ‘outsiders’ or the use of a hybrid gimmick to ‘insiders.’