The new aero package of the Hyundai i20 Coupé WRC was the most visible aero issue of the 2020 edition of Rally México. But there were more which are worth reviewing, such as the traditional poor reliability of some aero parts in the rough Mexican stages, or the beauty of the dust flow visualization images obtained in the first gravel event of the season.
Hyundai aligned in México three cars with the new aero modifications they had tested in the pre-event tests developed last month in Southern Spain, as well as in Tanak’s car in Rally Serras de Fafe e Felgueiras run two weeks ago. The modifications have been designed to increase downforce generation at both ends of the car while taking care of not modifying the aero balance.
D.Sordo/C.Del Barrio, Hyundai i20 Coupé WRC, Rally México 2020, ret. – picture by Martin Hlinka – eWRC.cz
The addition of a small wing in the front fenders has the primary goal of generating downforce on the front wheels, increasing its grip and reducing understeer. But there is a secondary goal: the wing allows a better redirection of air towards the rear of the car. To better conduct the airflow, the side mirrors have been modified: the arm support is now less prominent.
Hyundai I20 Coupé WRC side mirror in Rally México 2018 (left) and 2020 (right)
Hyundai I20 Coupé WRC side mirror in Rally Catalunya 2019 (left) and Rally México 2020 (right)
The reason behind this modification is most probably to better channel the air towards the new side wing included in the new design of the rear wing, making it more effective in generating additional downforce at the rear of the car.
Hyundai i20 Coupé WRC new side wing – picture by Julian Porter
But, behind the new design of the rear wing, there is also an additional goal: to increase the downforce generation while cornering. To achieve that, the shape of the upper wing was modified, now following the vehicle’s shape, leading to more vertical side ends which allow increasing the impact of air during the corners, which translates into higher downforce. The same goal is behind the introduction of two vertical strakes at the wing ends. These two modifications allowed to include thinner support arms for the upper wing. The only potential drawback of this modification is a potential reduction of their reliability, as thinner supports might break easier in the case of a rear impact during a stage, leading to rear wing loss which would turn the car undrivable.
T.Neuville/N.Gilsoul, Hyundai i20 Coupé WRC, Rally México 2020, 16th – picture by Honza Froněk – eWRC.cz
The front winglet is located on top of the front fender, and it includes a small end plate, to better separate low-pressure air (above) from high-pressure air (below), making it more efficient. It is located at approximately the same height as that of the Yaris WRC, which is more a deflector than a winglet. While the main goal of the Hyundai solution is to generate downforce, the goal of the Toyota deflector was to deviate the main airflow so the cooling air from engine bay could be removed through the orifices on top of the fender. Note that the angle of attack of the Hyundai’s winglet is smaller, which means that it generates lower air resistance (drag).
Hyundai i20 Coupé WRC (above) and Toyota Yaris WRC (below) front fender detail
The new rear side wings are similar in design to that used in the Fiesta since 2017, while Toyota changed it last year, to a smaller and less prominent wing. The comparative with the side wing of the Fiesta show, as major differences, the side of the Hyundai is wider, has a longer side end and a small Gurney flap at the rear of the wing.
It is too soon to evaluate how well the new aero is performing versus the old package and the competitors. Next events, and especially in the fastest stages of Rally Finland, will show.
As the first gravel event of the season, Rally México brought back images we had left behind since Turkey 2019. On one side, the reliability of aero parts was again put under test in the rough and compited Mexican stages.
T.Neuville/N.Gilsoul, Hyundai i20 Coupé WRC, Rally México 2020, 16th – picture by Vladislav Maschl – eWRC.cz
Neuville lost part of his rear wing in SS5. The image below allows distinguishing the different profiles of the Hyundai’s new rear wing: an inverted airfoil in the upper wing, and a plate in the lower.
T.Neuville/N.Gilsoul, Hyundai i20 Coupé WRC, Rally México 2020, 16th – picture extracted from WRCplus images
Other cars also lost part of their aero package, such as the side package (Greensmith/Edmondson) or the front splitter (Lappi/Ferm), while the Toyotas suffered from losing the front lip (Ogier/Ingrassia and Rovanperä/Halttunen).
G.Greensmith/E.Edmondson, Ford Fiesta WRC, Rally México 2020, 9th – picture by Vladislav Maschl – eWRC.cz
E.Lappi/J.Ferm, Ford Fiesta WRC, Rally México 2020, ret. – picture by Honza Froněk – eWRC.cz
K.Rovanperä/J.Halttunen, Toyota Yaris WRC, Rally México 2020, 5th – picture by Martin Hlinka – eWRC.cz
On the other hand, the beautiful images of dust flow visualization behind the cars came back in México, showing how well the aero parts perform. Especially in the spectacular images taken from helicopters.
E.Evans/S.Martin, Toyota Yaris WRC, Rally México 2020, 4th – picture by Toyota Gazoo Racing WRT
Cooling was not a problem anymore in México. It seems that teams have learned and improved from previous experiences, and there was no report of any cooling incidence…except the engine overheating that caused Sordo/Del Barrio retirement, possible due to a previous mechanical problem, while the fire in Lappi/Ferm car was suspected to be caused by an oil leak, possibly after the impact when they lost the front splitter.