Ferrari introduced a modified floor at the Japanese Grand Prix as it continues work on its four-time race winning F1-75.
If you take the underfloor as a complete unit, the diffuser can only increase the speed of the airflow that comes in through the leading edge, plus any leakage along the sides of the floor.
The expansion – and more importantly the expansion rate – of this flow coming along the underfloor is what creates the low pressure under the car and increases the overall downforce.
It’s not like a wing, where it’s all about accelerating the airflow over its lower surface. The underfloor works in conjunction with the track surface, so in effect, it’s more like half of a venturi. Try to expand the flow too quickly or too much and you lose control of it with the flow separating somewhere along the underbody surface.
So, in effect, the balancing act is the detail of the leading edge along with the leading-edge splitter positions.
Ferrari’s Suzuka underfloor featured a revised leading-edge splitter arrangement. By removing this small section of the outer splitter, it will alter the amount of flow that the diffuser tries to pull through the underfloor as opposed to what spills around the outer surface of that outer splitter.
One major point to remember is that you can’t just force more airflow into the leading edge of the underfloor, the diffuser has to pull it through.
As for the revised position of the floor stay, it wouldn’t surprise me if it has been moved inboard to allow a little more flexing of the outer foot.
With the vertical acceleration limits the FIA have now put in place, it probably means that most teams are having to run the cars with a slightly higher rear ride height.
By moving this stay inboard, it means that it still supports the main section of the floor. But it also allows Ferrari to raise its rear ride height while allowing the floor foot to flex slightly more to overcome that extra ground clearance.
