Lluís Vázquez takes a close look at the modifications to the Hyundai i20 WRC aero package in the lead up to the season-defining Rally Finland.
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During the first week of July, Hyundai developed a series of tests to evaluate some modifications of the front aero package of the i20 Coupé WRC.
The tests took place in the area close to Jyväskylä, with Andreas Mikkelsen and Andreas Jaeger as the test driver and co-driver on the first day, followed by Neuville/Gilsoul, and the recently signed couple of Craig Breen and Paul Nagle the next.
The goal seemed to be to increase grip at the front axle as well as to improve the aero car balance.
Photo: Henri Vuorinen Photography
The car included a new design of the front dive planes, with an increase in the size of the existing (upper) plane.
The inclusion of a second plane and the addition of a small vertical strake in the front splitter were featured. The front fenders had been modified, also.
Andreas Mikkelsen, Monte Carlo Rally 2019. Photo: llluis555 for WRCWings
The original dive plane (A in the picture below) was enlarged, while a small lip added in the rear side and in the rear end.
A bigger area means higher downforce generation, while the addition of side lips is intended to better channel the air onto the car sides. Note the difference in size with respect to the original, in the picture above.
The addition of a second dive plane, under the existing one, also contributes to generate higher downforce at the car front, in order to get more grip, as well as to generate vortices alongside the car.
It is known that the airstream leaving the dive planes generate a row of vortices on the car sides that act as a barrier for the air trying to enter under the car.
The result is a cleaner and faster undercar flow, lower pressure and higher downforce generation.
Thierry Neuville, pre-Finland test, July 2019. Photo: Henri Vuorinen Photography
Also, the second plane is welcomed in terms of reliability - losing the sole dive plane in any impact results in severely hampered grip.
The new plane is located under the existing one, and the rear end is supported on the front fender, generating a dead end underneath, like in any other current WRC car.
Hyundai i20 Coupé WRC Rally Catalunya 2017 pre-event test (left) and Rally Finland 2019 pre-event test (right).
The new dive plane design is very similar to that of the Toyota Yaris WRC, but with some minor differences. Toyota’s planes are longer in the frontal (bigger area) especially the lower of the two, which reaches the air intake area, and they incorporate the side lip all over the external side, while Hyundai has included a lip in the rear end of the top plane.
Toyota Yaris WRC, Rally Catalunya 2019 pre-vent test. Photo: llluis555 for WRCWings
The new solution is similar to the original design included in the i20 in 2017, but with some differences: the rear end of the upper plane does not interact with the front fender as in 2017, and the side lips included then have been removed or significantly reduced in size.
H. Paddon/J. .Kennard, Hyundai i20 Coupé WRC, Tour de Corse 2017
A vertical strake (B) was added on both sides of the front splitter, in order to better channel the airflow under the lower plane, while preventing air to exit laterally.
The strake minimizes the interaction of air with the external main flow, which would convert in an energy loss and a drag increase. This solution has also been used by Toyota and Ford since 2017.
The third big modification included is the modification of the front fenders. The side lip was removed, as well as the inverted-wing shaped lip profile, at the top rear end of the fender.
Photo: Henri Vuorinen Photography
Picture above also shows an increase in the area of air vents in the rear of the front fender. Such area increase would allow removing a higher amount of air from the front wheels, which would translate into a reduction of lift at the front axle, that is, higher grip. The bigger area has allowed giving more separation between the (4) louvres, which means lower pressure drop or more air to be removed.
Hyundai i20 WRC Coupé, Rally Catalunya pre-event test, September 2017. Photo: llluis555 for WRCWings
The main goal of all these modifications is to generate downforce at the front of the car, which should increase grip on the front axle, and improve the balance of the car.
It is intended that these modifications will reduce the under steering behavior of the car, which has been the object of complaint from Neuville and teammates in the recent events.
Craig Breen, pre-Finland test July 2019. Photo: Henri Vuorinen Photography
The first proper ‘rally’ test took place at Rally Estonia last weekend, with Mikkelsen at the wheel.
Their participation gave the team the chance of developing the aero in a two-day test free of charge. These days are not included inside the test days limit set by FIA (42)
The Norwegian duo finished second in Estonia, only behind Tänak/Jarveojä, while testing the new aero package and setting for the coming Rally of Finland.
A. Mikkelsen/A. Jaeger, Hyundai i20 Coupé WRC, Rally Estonia 2019. Photo: Rally Estonia
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The addition of a second dive plane, under the existing one, also contributes to generate higher downforce at the car front, in order to get more grip, as well as to generate vortices alongside the car.
It is known that the airstream leaving the dive planes generate a row of vortices on the car sides that act as a barrier for the air trying to enter under the car.
The result is a cleaner and faster undercar flow, lower pressure and higher downforce generation.
