Aero modification on the front of the Ford Fiesta WRC in Mexico

Updated in March 9th, 2019

M-Sport surprised everybody with the announcement through social media of the introduction of modifications in the aero package at the front of the Fiesta WRC the day Rally México started. According to the note published, and thanks to the sustained development work carried out with Ford Performance, they introduced some further aerodynamic advancements on Elfyn Evans’ Ford Fiesta WRC at this weekend’s Rally México, consisting in a revised front bumper design with updates to the dive planes improving the downforce efficiency. Their plan is to have the update on both cars in Corsica. The information included the picture below, where it is difficult to appreciate any difference with the original design of the front bumper. Let’s review what the modification is.

E.Evans/S.Martin, Ford Fiesta WRC, Rally México 2019, 3rd – picture by M-Sport

The modification consists in the increase of space between the vertical strake (with a green sticker of Castrol) and the bumper (with the Sparco sticker), as the bumper has been retracted. Such modification allows to include a wider lower dive plane. The comparative with the original design (picture below) allows to better see the change.

Ford Fiesta WRC 2019 México (left) vs 2018 (Wales, right)

Note the difference in the space as shown by the yellow lines in pictures below. The increase in space allow more air to flow under the dive plane, allowing to increase its efficiency.

In the pictures above, note the different shape of the Sparco sticker, to see the modification: from convex (old bumper) to concave (new bumper), a bigger space for airflow has been created, behind the vertical strake.

The increase in size of the lower dive plane can also be seen from the picture below, as contour is marked with a yellow line.

E.Evans/S.Martin, Ford Fiesta WRC, Rally México 2019, 3rd – picture by M-Sport

Other pictures recently published allow to confirm the increase in size of the lower dive plane.

E.Evans/S.Martin, Ford Fiesta WRC, Rally México 2019, 3rd

The increase in size of the lower dive plane, as we already reviewed in this previous post, allows to increase the generation of downforce at the car front. This means to improve the grip of the front axe, what translates into a less understeering car. It also contributes to improving the balance of the car, as much of the downforce is generated at the car rear, thanks to the rear wing and diffuser. So any improvement at the car front will reduce the difference, making the car more balanced and easier to drive.

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