30 Mar: Inside Citroen’s new C3 R5

… The Inside Story on Citroen’s New R5 Challenger …

FRANÇOIS WALES, Development Director, Customer Racing Vehicles …

Q. What were the specifications for the C3 R5?
A. The idea was to start from scratch. Obviously, the aim was for it to be reliable and fast, especially given that the standard in the R5 class – which was already high a year and a half ago when we began development work – just keeps on going up as new competitors join the category.

Q. What are the challenges posed by the R5 category?
A. First of all, there is very little room for manoeuvre (five upgrade tokens in the first 24 months, five others after) once the car has been homologated. Similarly, in terms of the chassis and suspension systems, the number of potential interfaces is very limited. On tarmac, the front strut is angled towards the rear, whilst it leans forwards on gravel. We are the only manufacturer to have proceeded like this, and whilst it is fairly straightforward to do this in the WRC, it’s a lot less easy in the R5 class! As regards the engine, the restrictor/pop-off valve combination makes these machines particularly complicated: everyone has more or less the required power and torque on the engine test bench, but the differences then come at the rallies, when factors like altitude and temperature vary. This is why we invested in a much more powerful ECU, involving considerably more fine-tuning.

Q. How did development work go?
A. We started work on preliminary project drawings at the end of 2016, but we didn’t really begin proper design work, based on the C3, until January 2017, the first road tests being held in September 2017. Engine endurance tests were completed without incident. We have tested on pretty much all types of tarmac and have defined a good basic set-up. The same goes for gravel, where we have held sessions at a wide variety of test bases. We are now going to use this year to fine-tune our set-up at specific events such as Monte-Carlo, Sweden, Finland, Wales GB and Germany.

Q. A lot of drivers were involved in testing: Stéphane Lefebvre and Yoann Bonato, as well as the likes of Craig Breen, Kris Meeke, Yohan Rossel, Paolo Andreucci and Simone Tempestini. What was the aim?
A. We believe that a fast, powerful rally car must also be versatile, especially when it comes to a customer racing product. This is why we decided to use a small panel of drivers so we could get a comprehensive view and quicker understanding of any areas that needed to be corrected on the car.

PIERRE BUDAR, Citroën Racing Team Principal
“We have set Stéphane Lefebvre a target of winning the WRC2 championship, in order to show the potential of the car, both in terms of performance and reliability on a wide variety of surfaces and in what is a highly competitive series. There is a considerable sales & marketing side to it too. Stéphane will be in the spotlight, showcasing the brand. He knows the car well and will be sharp coming into the rallies, especially as each time, he will have a pre-event test. He also has experience of the events since he contested most of them last year in the WRC. After the Tour de Corse, he will be competing in Portugal and Sardinia, and then we’ll see what happens after that.”

To ensure it is competitive in the WRC2, and in the various FIA regional championships (ERC and MERC) and national championships, Citroën Racing has produced a radically different car to its predecessor. Led by Olivier Maroselli, the team of twenty or so people involved in the project started from scratch. This approach was also guided by the fact that the standard in the category is higher than ever before, with several high-profile manufacturers seriously involved. The main challenge concerns the regulations, which are much more restrictive than in the WRC as regards homologation, competitors only being allowed five upgrade tokens in the first two years (only two of which are allowed for safety or reliability reasons) and then five more in the next two years. This is why is so important to get things right first time!

After the traditional design stage in September 2017 the project team began work testing the car in a wide range of rallying conditions. The tarmac version of the C3 R5, fitted with eighteen-inch tyres, was put through its paces in Corsica, as well as in the east (Vosges) and south (Tarn) of mainland France. The car also had its first outing in a competitive setting as one of the zero cars at the Rallye du Var in November of last year, driven by Yoann Bonato. Meanwhile, work continued on the gravel version with sessions conducted on gravel roads in Fontjoncouse, near Narbonne, Cardona in Spain and Mazamet, to the north of Carcassonne.

Six thousand kilometres of testing later, Citroën Racing is now able to present an accomplished product. Further test sessions are scheduled for later this year.

“We set ourselves some very ambitious targets,” explained Olivier Maroselli, the project manager. “Targets that we have met by working in three major areas. First of all, reliability and heat management with all the internal parts of the engine. We also paid special attention to the cylinder head, to increase permeability on the intake and exhaust ducts. The last major area of development was the car’s electronics, with a more advanced ECU than what we have used in the past. The purpose of this was to have a much more functional anti-lag system and therefore get much better response from the accelerator during in-gear acceleration. But the idea was also to be constantly as close to the maximum authorised boost pressure, without opening the pop-off valve, which always has a highly detrimental effect on power. All of this means that the engine is now undoubtedly one of the car’s major strengths. All the drivers were in agreement that the car has bags of torque, but we also know that it is also well placed in terms of power, with a higher rating than its rivals.”

The C3 R5 is fitted with a Sadev gearbox, specially designed for the specific requirements and constraints of the R5 category. “It’s a question of safety, really,” commented Olivier Maroselli. “Although some of the internal components are familiar, and therefore tried and tested, we nonetheless chose to design our own architecture. Our packaging is different in terms of both the width and the height of the gearbox outlets. This is because they have a direct influence on the transmission angles, and therefore the maximum travel allowed.”

The C3 WRC, the C3 R5 has two different front suspension geometries for tarmac and gravel, to optimise the chassis and suspensions systems to meet the specific constraints of the surface in question. “As the number of interfaces authorised between the hub carrier, the strut, the suspension arm and the tie rod are very limited, this was no mean feat,” explained Olivier Maroselli. “But we chose to incline the strut towards the rear on tarmac, for the purposes of kinematics, and towards the front on gravel, mainly to do with travel. This is another of the car’s strengths, because we didn’t have to compromise on the designs chosen at all. We were also determined to ensure all of these parts were at the minimum weight. This involved using Reiger shock absorbers with their aluminium struts which also helps to keep the weight down.”

Citroën Racing were equally determined to ensure ease of maintenance for the C3 R5, whilst also paying special attention to the durability of the parts selected. “Yes, this was clearly one of the areas we worked on,” admitted Olivier Maroselli. “The gearbox and the front end, for example, can be removed very easily. We have also made a lot of progress on the bodywork, by investing in multi-material technology so that there are rubberized components in all the lower parts of the bumpers and in some areas on the wings. They are therefore more resistant to wear and distortion. Similarly, we covered a lot of miles in tests on really rough gravel surfaces such as at Fontjoncouse, and we noted a vast improvement in the ageing of the body and all of the subframe. Damage to consumable parts, like the protective skidplate, is at a really very good level and that is undoubtedly a plus for running costs.”

Q. What sort of welcome can C3 R5 customers expect here?
A. I think it’s safe to say we will be really looking after them! We already have about twenty confirmed orders, from France, but also from Belgium, the UK, Spain and Portugal. However, it has already become popular outside of Europe, particularly from Latin America. We have deliberately limited our assembly capabilities to about thirty cars this first year, before ramping up to close to seventy next year.

Q. In what specification is the car sold?
A. The car is pretty much ready to go and set times straight away! It will be sold fully-assembled, by which I mean lamp pods, two spare tyres, a set of wheel rims, intercom/radio, helmet storage net, co-driver torch, harness cutter, a collection of shims, springs, and there are doubtless other items I’ve omitted.

A. We have a dedicated team of technical advisors, and as part of the market launch of the C3 R5, they will be available as much as possible to provide on-the-ground support and advise the crews and teams. They are equally capable of guiding the drivers about set-up options as advising the mechanics if they are unsure as to how to carry out a technical operation of one kind or another.

Citroën Racing Shop
Tel.: + 33 (0)1 30 11 27 00
E-mail: racingshop@mpsa.com
Customer Racing Technical Support
Tel.: +33 (0)1 30 11 26 77
E-mail: technicalsupport@mpsa.com


Structure – Reinforced body with welded, multi-point roll cage
Bodywork – Steel and composite fibre

Citroën Racing – 1.6-litre turbocharged direct injection with FIA 32mm restrictor
Bore x stroke – 77×85.8 mm
Capacity – 1,598cc
Maximum Power – 282bhp at 5,000rpm
Maximum torque – 420Nm at 4,000rpm
Distribution – Double overhead camshaft valve train driven by chain, 4 valves per cylinder
Fuel feed – Direct injection controlled by SRG Magneti Marelli unit

TRANSMISSION – Four-wheel drive
Gearbox – Sadev Five-speed sequential – Manual control
Differential – Front and rear mechanical, self-locking
Clutch – Cerametallic Twin-disk

Front – Ventilated disks, 355mm (tarmac) and 300mm (gravel), Alcon 4-pistons calipers
Rear – Ventilated disks, 355mm (tarmac) and 300mm (gravel), Alcon 4-pistons calipers

Shock absorbers – REIGER three-way adjustable shock absorbers (low-and-high-speed compression and rebound)
STEERING – Hydraulic power-assisted steering

Tarmac – 8×18″ wheels – Michelin tyres
Gravel – 7×15″ wheels – Michelin tyres

Length / Width – 3,996mm / 1,820mm
Wheel base – 2,567mm
Track – 1,618 mm (front and rear)
Fuel tank – 81 litres
Weight – 1,230kg