Revealed: The tiny Red Bull changes that made a huge difference in Japan

Matthew Somerfield 07 Apr 2025 5:00 PM

The majority of the updated components that arrived at the Japanese Grand Prix belonged to the chasing pack, with only Red Bull out of the ‘big four’ making changes for Suzuka.

There were still several other omissions but, with new parts for Racing Bulls, Haas, Williams and Sauber, we have plenty to dig into.

Japanese Grand Prix: Chasing gains

Red Bull’s package of components that arrived at the Japanese Grand Prix mainly revolved around their cooling requirements, with a revised engine cover arrangement and enlarged rear brake duct outlet prepared, in order to deal with the demands of Suzuka and upcoming events with similar requirements.

The changes made to their engine cover are subtle, with the main cannon-style outlet reprofiled to better manage the airflow externally, over the bodywork and the heat being rejected from the outlet, in order that the performance of the beam and rear wing elements are also improved.

The alteration also facilitates the removal of the louvred cooling panel on the side of the engine cover (inset, louvred panel in the smaller inset, above), reducing the associated losses that may be accrued here too.

The new rear brake duct outlet (see inset) has blanking options available, in order that the size of the outlet can be trimmed to the exact requirements of the given circuit, rather than having numerous different solutions on hand.

Meanwhile, there’s also been some adjustments made to the rear suspension fairing, with the team reporting adjustments to the lower rear suspension wishbone (front leg arrowed), in order to better align the airflow both locally and in combination with the surrounding surfaces.

It does, however, also appear that the upper wishbone fairing may have been modified too.

It’s also worth noting that the two Red Bulls were set up differently for qualifying and the race, as Verstappen opted for less downforce than Tsunoda, as the four-time World Champion used the same low downforce arrangement that had been introduced at the Australian Grand Prix.

Racing Bull have also made a small modification to the VCARB02’s halo fairing at the Japanese Grand Prix, as they begin to look for small details that might improve performance of the car, having already made some tweaks to the car in China.

The adjustment comes to the vertical vane that’s mounted on the top of the rear leg of the halo, with the flat-edged solution used in the opening two rounds of the championship (inset) traded-in for a more rounded variant (grey arrow).

Albeit a small aerodynamic appendage, the surface will alter the airflow’s passage downstream into more critical areas of performance, such as the interface between the engine cover and sidepods, leading into the coke bottle region.

Williams made changes to their front wing in Japan, as they look to help balance the performance of the car front-to-rear.

This consisted of two major changes, with a notch cut out of the lower rear corner of the endplate (inset, arrowed) and a pinched section added to the uppermost flap (arrow) to help create a physical division between the inner and outermost sections of the wing.

The latter of these two changes is similar to the design feature first seen on the Aston Martin at Imola last season, albeit their solution also saw the flap below altered too.

Aston Martin have dropped the solution this season but it appears Williams have found a way to integrate into their design to make gains.

The upshot of the redesign will be an adjustment to the amount of outwash that’s being generated by the outboard portion of the wing, providing a better distribution for the inboard section of the wing to generate downforce and help balance the car.

Sauber continue to pile new parts on the C45, as they look to leapfrog their way up the standings, with a new floor, beam wing and rear wing fitted to their cars in Japan.

The new beam wing is an addition, with the team retaining the main, lower element and installing another element above and ahead of it, in order to create a bi-plane style arrangement.

The changes to the rear wing centre around the mainplane’s design, with the spoon-shaped transition altered across the element’s span.

Meanwhile, the changes made to the floor included the floor fence arrangement, floor edge and the diffuser.

The team also appear to have confirmed that the new sidepod bodywork, that was introduced in China, is a step in the right direction too, as Bortoleto joined Hulkenberg in its use this weekend, rather than sticking with the old arrangement, as he did in China (above).

Comparing the two designs, you’ll note that the solution on Bortoleto’s car has a depression in the flank of the downslope, whereas the bodywork has literally been patched on Hulkenberg’s C45, with the lines where the new section is mounted clearly visible.

It’s an interesting approach that’s been taken by Sauber, as it means they haven’t had to completely remanufacture the entire sidepod bodywork, undoubtedly saving them some money but, it will likely come at the expense of a small amount of additional weight as a consequence.

The leftovers

We’ve already had two technical image galleries from the Japanese Grand Prix but, with another batch of images landing on my desk after they’d been published it would be criminal not to show off the detail on offer.

👉 Revealed: The secret design details uncovered at the Japanese GP

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The Alpine A525 being prepared as a chassis up rebuild after Doohan’s crash.

A look inside the right-hand sidepod on the Williams FW47, which shows how much space is left over internally, rather than the bodywork being shrink-wrapped to the components as it was in the previous era of regulations.

The front of the Alpine A525’s steering wheel, with the various buttons and rotaries used to control the various powerunit and chassis parameters all on show.

The front suspension upright on the Aston Martin AMR25 prior to the brake components being installed.

A close up of the exhaust layout on the Alpine A525 which is flattened against the floor to allow more space for the ramp-style sidepod bodywork above.

For comparison, a look at the exhaust layout on the Sauber C45, with the manifold pulled up around the Ferrari powerunit, rather than being laid flat.

The Mercedes powered teams, including Williams shown here, also have a more laid down exhaust layout.

The steering wheel from the Red Bull RB21, which has a notably different shape to the aforementioned Alpine wheel.

A great view of the contours on the Aston Martin AMR25’s underfloor, as it’s lifted away from the circuit following an excursion into the gravel.

A close up of the flap and endplate juncture on the Haas VF-25’s front wing, with the team using the semi-detached flap layout for the three rearmost flaps, whilst an additional pair of outwashing winglets are also mounted in the rear corner.

Peeking into Sauber’s garage whilst the floor is off the C45 affords us a great view of the forward section of the underfloor and gives us insight into the various geometries employed on the fences.