Aerodynamic fine tuning in January’18 WRC tests

Since the first week of 2018, WRC Teams have been working hard in different road tests to get the cars ready for the coming Monte Carlo. Toyota and Hyundai have been the earliest teams to start testing, both on South of France roads. Then Ford joined them, after the WRC 2018 season presentation held in Autosport International Show, in Birmingham, where new liveries were presented, and finally Citroën, just the week before the start of the season.

All cars used in these tests had nearly the same configuration already seen in last December tests, with only some minor changes, as some of the Team principals already confirmed during Birmingham presentations.

Ford Fiesta WRC

Chris Williams, M-Sport’s chief rally car engineer confirmed, in an interview with Martin Holmes for Rallysportmag, that they are working on lots of little things, but no big changes are expected in the next months. He reckons “there’s stuff coming more in aerodynamics, but it’s only small gains”.  Also that “we are reasonably happy with our aero package, we’ve changed the sills and some other bits and pieces, but again we don’t make a big step change. We are just refining the original architecture we have”.

Pictures from Ogier/Ingrassia’s test in Southern France in the third week of January seem to confirm his statement, as thinner side skirts (sills) can be identified in the car, compared to those used in 2017.


S.Ogier/J.Ingrassia, Ford Fiesta WRC, test in France, January 2018 – picture courtesy of PlaneteMarcus

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M.Østberg/T.Eriksen, Ford Fiesta WRC, Rally Catalunya 2017, 5th

The reason for this modification, combined with a modification in the material the skirts are made of, is to improve the reliability of side skirts, in order to make them more resistant to impacts. The role of side skirts is to reduce the amount of air from entering below the car from both sides, which means higher downforce as flow below the car is faster and undisturbed. This would help the British car to turn faster, especially on asphalt roads. Sebastian Ogier should be the most benefited, as surprisingly he did not get any win in any of the three pure asphalt rallies last year (Corsica, Germany and Catalunya) – something he had done in all of his previous four titles.

Williams also stated in that interview that “Slowly all the cars are going in a similar direction now. You will see aerodynamic features that are similar amongst the cars, slowly going one direction, though there are some differences still”.

Hyundai i20 Coupé WRC

Michael Nandan, Hyundai Motorsport Team principal, also interviewed by Rallymagsport magazine, admitted that for them too “there will be more fine-tuning for our aerodynamics”. And the images from the January tests also seem to confirm.

Additional louvres have been incorporated in the lower air outlets of the rear bumper of the i20 Coupé: pictures below show the new louvres, compared to the configuration used in Australia by Neuville, with no louvres in the lower air outlet. The addition of louvres helps to channel exiting hot air into the desired direction, to get an additional aero benefit.

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A.Mikkelsen/A.Jaeger, Hyundai i20 Coupé WRC, test in France, January 2018 – picture from Davideo productions video

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T.Neuville/N.Gilsoul, Hyundai i20 Coupé WRC, Rally Australia 2017, 1st

This space appears to be free also in the car pictures Hyundai has released during the WRC presentation in Birmingham this week. We will have to wait until Monte Carlo to confirm the final decision on this point.

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Hyundai i20 Coupé WRC, 2018 livery

Toyota Yaris WRC

The front of the Yaris WRC has incorporated the front trapezoidal air inlet into the original design of the front bumper. The image below shows the evolution of the bumper, from the one seen in Wales Rally 2017 (bottom picture), to that tested in Southern Spain in November (center) and the final design tested in January (on top).

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E.Lappi/J.Ferm, Toyota Yaris WRC, Test in France, January 2018

E.Lappi/J.Ferm, Toyota Yaris WRC, Test in Almeria, Spain, November 2017

J.M.Latvala/M.Anttila, Toyota Yaris WRC, 2017 Wales Rally, 5th

Pictures by Ciryl Scharff (top), Fernando Cruz (center) and Lukasz Mikulski (down)

No other differences have been observed in the Yaris. But it is worth reviewing this picture, with detail of front brakes air outlet on the upper and rear side of the front wheel arch, from the recent Autosport International show in Birmingham.

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Toyota Yaris WRC, Autosport International show 2018, Birmingham

Part of the air is redirected upwards, under the protection of the upper winglet, to avoid mixing this airflow with the airflow coming from dive planes. The rest of the cooling brakes air is removed downwards, through the rear louvres.

Citroën C3 WRC

Citroën has been the last team to develop some tests during January 2018, just the week before the Rally Monte Carlo. The pictures and videos released from these tests do not show any modification, so we will have to wait until Monte Carlo to confirm if the team faces the new season with the same aero configuration or they keep modifications secret until the very last moment.


K.Meeke/P.Nagle, Citroën C3 WRC, Test in France, January 19th, 2018 – picture by Julien Prioux (Planete Marcus)

All other modifications for 2018 were already reviewed in previous posts:

December’17 WRC tests

Toyota Yaris WRC November’17 test

Hyundai preWales’17 test

Citroën C3 WRC October’17 test

Hyundai preCatalunya’17 test


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