Ferrari SF-25 floor: pressure drop issues due to management challenges. We analyze the solutions studied for the diffuser by Ferrari and McLaren.

Ferrari needs to get in line. The SF-25 is a good Formula 1 car that, until now, has never managed to extract the maximum performance. Not even in the Sprint Race won by Lewis Hamilton at the 5.451-kilometre Shanghai International Circuit, or in the pole position from the day before, where the Red car was far from perfect. This is why there is confidence. The upcoming updates will serve to enhance the interaction between mechanics and aerodynamics. An urgent necessity to stabilize the car’s platform by widening the operating window of the single-seater.

Today, we have the opportunity to analyze two very interesting images, regarding the solutions studied for the diffuser by Ferrari and McLaren. The perspective is not exactly the same, but various considerations can still be made. Let’s start by observing the two Venturi channels. Already in this area, we find different solutions. McLaren seems to opt for a more rounded channel roof.

In the case of the SF-25, instead, the channel is decidedly squarer. In this case, the difference lies in the management of the vortices that develop inside the floor and their housing in the path that the fluid mass takes toward the diffuser. Moving on, let’s observe the keel. The shape differs significantly between the two versions. In the case of the Red car, the lateral wall is more linear.

On the other hand, for the MCL39, we find several devices. First of all, the junction radius is wider, and there is a lip that guarantees an additional drop in local pressure, very useful for increasing the vertical downforce in that area. In the specific of the Italian F1 team, these devices are not present. This is a characteristic established for the Prancing Horse, which over the years has never tried to follow this type of design.

A more linear keel is easier to manage, and often simplicity is also synonymous with greater reliability. Having a localized depression brings more downforce if managed correctly. However, to make such a design work, a very stable platform is needed. Greater and unexpected floor excursions often put the stability of the flow in these areas under serious strain.

This conservative choice by Ferrari is linked to the fact that the Italian car uses a higher degree of squat on the rear suspension. It is a technical feature designed during development that cannot be considered a flaw. On the contrary, if managed correctly, it can deliver excellent results, taking the lap in a different way compared to the competitors. The problem for the Prancing Horse is precisely this: at the moment, the setup construction is not paying off.

In the diffuser area, we find other rather marked differences. We see that Ferrari has chosen to use a softer drop to better stabilize the flow in the diffuser’s slipstream and, consequently, avoid fluid detachments under various driving conditions. Of course, the diffuser does not stall completely, but there could be areas where the fluid flow detaches under certain driving conditions.

By “driving conditions,” we mean the various configurations of the car’s floor. A macro component that, as we know, is subject to various and continuous changes in incidence due to suspension elasticity. The yaw angles, such as roll and pitch, vary continuously when the car goes out on track.

The type of oscillation of these angles is appropriately reduced by F1 teams, more or less, also because we cannot forget that mechanical grip, as well as downforce, must still be taken into account. Even in this case, since the MCL39 is generally a stiffer car, it can benefit from an even more aggressive diffuser slipstream design.

The lower downforce of the SF-25 is a fact, which has been observed in many corners during the first two races of the 2025 Formula 1 World Championship, in Australia and China. The current problem concerns a decisive aspect. We are referring to the ability to maintain the same downforce across a wider range of driving conditions. In technical terms, this means the aerodynamic map is narrower. And this is precisely the strength of the British team.

A team that, already in the previous racing season, was working to flatten the rear downforce peak because it had too much downforce at the rear end. The same thing applies to Red Bull. Over time and with experience, McLaren has been able to appropriately modify the load distribution along the floor, to the point where it currently shows a more oversteering behaviour.

In fast corners, the vertical downforce is balanced and very stable, a factor that makes a huge difference on track. Ferrari is still working on this important aspect, as it cannot maximize the vertical downforce to distribute it more evenly and effectively. A clear step forward is needed for Ferrari, that the Italian team thinks and hopes to achieve with the upcoming aerodynamic updates, which are almost ready.

— see video above —