After two months of intense redesign and testing work, the new season started with the 87th edition of the Rallye Monte-Carlo. All teams except Hyundai had used that period to further develop the aero package of their cars. The surprise was that only M-Sport introduced an aero modification in Monte-Carlo, while Citroën and Toyota left their modifications aside, waiting to homologate them for future events.
T.Neuville/N.Gilsoul, Hyundai i20 WRC Coupé, Rally Sweden pre-event test, January 2019 – picture extracted from Anthony Bailet excellent video
Only three days after the end of the season starter event, teams have started to develop their Sweden pre-event tests, between Finland and Sweden. And in the end, it seems that Hyundai may be considering to evaluate additional modifications for their already competitive i20 WRC Coupé. The arrival of Andrea Adamo to Hyundai Motorsport and the pressure from the Korean manufacturer to finally obtain the expected results have catalysed the search for improved performance.
The current aero package of Hyundai was introduced back in Wales Rally GB 2017, with the only exception of the new side mirrors.
The main change for the team in the interseason was the replacement of Team Manager Michael Nandan by Andrea Adamo, former Customer Racing Manager. Nandan responsibilities included team management and technical development work. Adamo assumed the role of Team Manager, while Technical Development leader is to be named soon. The fact that he had started working in motorsport competition as a junior aerodynamics engineer in the DTM was already a good indication of the changes to come.
Also, Toyota has continued this week with their Rally Sweden pre-event tests. While Tänak and Latvala had done them before Monte-Carlo, it was time now for new recruit Kris Meeke to learn the car handling under snowy conditions. And the car used by Meeke includes again the modification on the louvres of the rear fenders, already tested by his teammates, but which was not used in Monte-Carlo.
This probably means that the modification is still under evaluation, or maybe the homologation process has not been totally completed. The modification (we already reviewed in a previous post) consisted of the replacement of the multi-louvred exit by a 3-louvre exit, allowing an easier air removal, due to the reduction in pressure drop. Also, the lower part of the fender vent was blocked, so the air was relieved at a higher speed (due to the reduction of exit area). The result of these modifications should be a more effective air removal, as lift caused by air accumulation in the wheel arch should be reduced.
Toyota Yaris WRC rear fender comparative: old (left) vs new (right) design
The profile of the lower part of the fender was also modified, reducing the space for the rear wheels turbulent wake, which has implications on the wake of the car: together with the blockage of the lower part of the fender vent, more air is sent to the top/center of the rear wake and less air to the lower, turbulent part of the wake. This contributes to a more homogeneous wake, which means lower drag generated by the wake.
The modification of the louvres do not require of any homologation. But as the design of the rear of the fender has also been modified, it is necessary for Toyota to homologate this modification before using it in any race.
T.Suninen/M.Salminen, Ford Fiesta WRC, Rallye Monte-Carlo 2019, 11th
M-Sport Ford World Rally Team also has been testing in Sweden this week. However, they were the only team that already introduced the modifications evaluated in the interseason tests in Monte-Carlo. As the team explained in their pre-event press release, the main modifications consisted in revisions to the rear bumper and louvres to improve performance and durability on the aerodynamics. Other modifications include new dampers and electronics, evolved lamp pods to incorporate adaptive lighting, and an engine upgrade which is expected to deliver an appreciable increase in performance.
Since last December, Richard Millener has been step up to the role of Team Principal, while Malcolm Wilson will devote more time to the commercial side of M-Sport as a business.
Ford Fiesta WRC rear fender 2018 (left) and 2019 (right) design
The modification of the rear bumper was first seen in the tests M-Sport carried out in Southern France in December, which we reviewed in a previous post. It consists in a width reduction (cut) of the external, lower portion of the rear fender vents, which also represents a reduction in the vent area and, consequently, a modification of the lower louvres width. The result is that part of the air from the rear wheels is now freely vented along the fender, while the rest is still vented through the louvres. So the reduction in venting area is compensated with the reduction of air to be removed through them. There are two reasons for the modification: aerodynamics and reliability. From an aerodynamic point of view, it represents an alternative exit to the air accumulated in the rear wheel arch. All this air was removed through the louvred exit with the new aero. The new modification seems to indicate that the louvred exit was not enough to remove all the air, thus causing some undesired lift due to hot air accumulation.
In terms of reliability, the cut to the fenders removes the most exposed part of them, so the risk of losing them is reduced. The original design, which was introduced in Finland 2018, already showed this was a weak point, as Ogier/Ingrassia lost one the fenders in the last jump of the last stage (Ruuhimäki 2).
S.Ogier/J.Ingrassia, Citroën C3 WRC, Rallye Monte-Carlo 2019, 1st
Citroën Racing Team hasn’t started yet Sweden pre-event tests. The 2019 version of the Citroën C3 WRC used in Monte-Carlo did not show any visible modification in the aero package. The C3 WRC is the only car still using the original aero package since January 2017, and even though different modifications were evaluated during the interseason tests developed in November and December, none of these were finally introduced for the season starter event. However, it is possible that they are gradually introduced after the next events, once the team is able to develop further test verifications.
The different tests the team developed during December test gave some clues about the potential modifications for the near future, with downforce both at the front and the rear of the car as one of the main goals. Tests in the next days will confirm if the team continues to work in this direction.
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