Published on November 2, 2017
After introducing significant aerodynamic changes in the cars aligned in Catalunya Rally, affecting dive planes and rear wing (we already reviewed in a previous post), Hyundai continued to work on additional modifications in the car, to increase their options in the battle for world drivers title. Such modifications could be first seen in Wales tests carried out during October, for the preparation of the penultimate rally of the season. In the end, they were only incorporated into Thierry Neuville’s car in Wales Rally.
H.Paddon/S.Marshall, Hyundai i20 Coupé WRC, Test in Wales, October 2017
Arch of rear wheels was the main object of the modifications. The front area of the arch was redesigned. Now it has a round shape, allowing air to flow up to the top of the arch, in a vertical flow direction, while original shape was designed to send air towards the side of the car, into a horizontal direction. The picture below shows comparative of new (Neuville) and old (Sordo) design, as included in Hyundai cars in the last Rally of Wales.
courtesy of Hyundai Motosport
T.Neuville/N.Gilsoul and D.Sordo/M.Martí, Hyundai i20 Coupé WRC, 2017 Rally of Wales
The picture on the right side below shows the flow of air under new design (Neuville’s car) compared to the horizontal flow in the original design (Sordo’s car).
In the top end of the arch, an additional winglet has been added, in order to help air flowing upwards, similar to that included in the rear arch of the VW Polo WRC 2017. Also, the door has been modified, as the lower part has been covered by a flat portion, eliminating a small dead end.
The goal of this modification is probably downforce: by sending air upwards, additional pressure can be obtained over rear train. Also by sending additional airflow onto rear wing, whose end plate was increased in size in Catalunya Rally, maybe to help collect the additional airflow generated by the new arch modification.
The picture above shows new design, versus old design in Neuville’s car in Montecarlo rally (below).
The rear part of the arch has also been modified. A higher number of louvres (A) are present in the new one, which starts from the top of the arch. And they are wider than in the old design. Also, rear bumper has been modified, and side air outlets (B) have also increased in size with respect to original design.
T.Neuville/N.Gilsoul, Hyundai i20 Coupé WRC, 2017 Rally of Wales, 2ond
Previous design contained a lower number of thinner louvres, and lower amount of air from cooling brakes could be removed. Also, orientation seems to have changed: original design seems to force air downwards, while the new design shows horizontal canards.
courtesy of Michelin
A.Mikkelsen/A.Jaeger, Hyundai i20 Coupé WRC, 2017 Rally of Wales, 4th
The reason behind this modification is probably problems with rear brakes cooling. That would explain why all four Hyundai cars run in Wales with the NACA duct in the open position (on the left side), while in other rallies run at a higher temperature (such as in Finland in August) it was closed. These NACA ducts are designed to feed cooling air to rear brakes with minimal drag increase, as we reviewed in a previous post.
Modifications included in Catalunya and Wales Rally complete the new aerodynamic package of the Hyundai i20 Coupé WRC. As Seb Ogier and M-Sport won the titles in the Wales Rally, no further modifications are expected until next season from any team.