Aerodynamics of lamp pods in WRC cars
Night stages have become rather unusual in the current Championship, while, not many years ago (

Additional lamps or lamp pods have been a distinctive sign of identity of rally cars since its eruption. The image of iconic cars such as the Alpine Renault A110, the Lancia Stratos HF or the Porsche 911 Carrera RS that remains in many fan memories includes them as a sign of identity of a rally car.

It was normal for rally cars to include the light pods since early in the morning, and they were covered with protectors for most of the day, for the happiness of publicizers, who rapidly found an additional location to include advertisements. How to forget the names of light manufacturers such as Cibié, Hella, Lucas or PIAA?

T.Fassina/M.Mannini, Lancia Stratos HF, Rally Sanremo 1979, 1st
The usual location of light pods and light bars, at the front of the car bonnet, represents a significant disturbance for the air flowing above the car, for what their size and design have an impact on the car aerodynamics, which is worth to review.

Traditional image of the WRC cars before Rally Montecarlo start, with light pods on
The current WRC car generation has introduced different alternatives for increasing their lighting capacity, and manufacturers have opted for different solutions, some of which have evolved since their first appearance in 2017.

Rallye Monte Carlo 2017 was the first opportunity to see the new WRC car generation, and lamp pods/bars were already present on that occasion. Three manufacturers, Citroën, Hyundai (with PIAA lamps) and Toyota (also PIAA), opted for the classical Halogen or HID (

T.Neuville/N.Gilsoul, Hyundai i20 Coupe WRC Rallye Monte-Carlo 2017, 15th

T.Neuville/N.Gilsoul, Hyundai i20 Coupé WRC, Wales Rally GB 2018, 5th
Hyundai was the only team to include a rear cover to the lamps (lamp pod), which surely contributes to

S.Ogier/J.Ingrassia, Ford Fiesta WRC, Rallye Monte-Carlo 2017, 1st
M-Sport was the first to introduce a lightning
In addition to lamp pods, additional lamps are usually required to illuminate both sides of the road. Hyundai and Ford opted for integrating such lamps into the body, contributing to

K.Meeke/P.Nagle, Citroën C3 WRC, Rallye Monte-Carlo 2017, ret.
On the contrary, Citroën and Toyota added external lamps for side illumination, thus increasing the drag of the car, due to its prominent position. In the case of the Citroën, the location of the side lights even affected the performance of the dive planes, as they represent an obstacle for air flowing to these planes.

J.M.Latvala/M.Anttila, Toyota Yaris WRC, Rallye Monte-Carlo 2017, 2nd
For the 2018 season, Toyota solved the problem of the side lamps of the Yaris, as they were removed from their original location and relocated into a lower position, allowing them to be integrated inside the front bumper and reducing the resistance to air flow (drag) significantly.

J.M.Latvala/M.Anttila, Toyota Yaris WRC, Rallye Monte-Carlo 2018, 3rd
Citroën did not

S.Ogier/J.Ingrassia, Citroën C3 WRC, Rally Monte Carlo 2019, 1st

E.Lappi/J.Fern, Citroën C3 WRC, Rallye Monte Carlo 2019, ret.
Also in 2019, Hyundai has shifted from HID lamps to a light pod based on LEDs, also from Lazer.

S.Loeb/D.Elena, Hyundai i20 Coupe WRC, Rallye Monte Carlo 2019, 4th

S.Loeb/D.Elena, Hyundai i20 Coupe WRC, Rally Sweden 2019, 7th
However, the new system possibly did not convince Andreas Mikkelsen, or maybe they suffered a lack of spare parts. In any case, in Rally Sweden 2019 the Norwegian driver came back to the original system, based on HID lamps.

A.Mikkelsen/A.Jaeger, Hyundai i20 Coupé WRC, Rally Sweden 2019, 4th
Aerodynamics of lamp pods
On a rally car with no lamp pod, air flows over the car bonnet, following exactly the shape of the bonnet, in what we call an attached flow. The pressure distribution over the frontal part of the bonnet usually shows high-pressure values on this area, due to the impact of air flowing against the car. This means this part of the car also contributes to downforce generation.


At night, due to the presence of lamp pods and bars, air cannot follow the shape of the bonnet, and, as a consequence, it becomes separated (detached). The first impact is that the pressure on the bonnet is reduced. This means that less downforce is generated, as air

In addition, air leaving the pod generates an unsteady wake. The smooth flow turns into
In conclusion, the presence of lamp pods/bars

Ford Fiesta WRC, Windshear Wind tunnel, Ford Performance, Charlotte (US), March 2018
In addition to the impact on aerodynamics, the addition of
also act as ballast, modifying the car’s handling characteristics.
Fortunately for the engineers (but unfortunately for rally fans), lamp pods/bars use is limited to a very few stages during the year. Also, their impact on performance seems to be limited, but not negligible. In any case, two of these night stages are the first two stages of the season (at least it has been in the last five years), so there is no better way to start the season than taking it seriously and optimizing the design of the lamp pods for a minimal impact on aerodynamics.
Very nice explanations, thank you! So how much is the influence of lamp pod aerodynamics on WRC/WRC2 cars? Or, in other words – what’s the difference in aerodynamics with/without the lamp pods?
Thank you.
Thank you! Difficult to quantify, probably not too much. But the presence of the light pod increases drag (as higher air resistance is generated) and reduces downforce at the car front, due to the flow separation caused by the pod.
Thank you. Also, you explained in detail the evolution of the lamps for side illumination. I have not seen this before and it really helps to understand what companies are doing and why they are doing this. Also interesting to see that not everybody has switched to LEDs yet.
Hyundai’s solution seems to feature with some openings beneath the lamps and louvres behind. I believe this could help to reduce the drag of the nightface.
Probably they are designed for light cooling, but even so they contribute to reduce drag, good point!