The same, yet different: production FABIA vs. rally FABIA

The same, yet different: production FABIA vs. rally FABIA

ŠKODA WORLD INNOVATION & TECHNOLOGY

Rally car development is constrained by strict rules set by FIA, the International Automobile Federation. But the work is no less varied and interesting for that. ŠKODA Storyboard takes us through the process, using the newest FABIA Rally2 bestseller as an example.

1. 6. 2022

The new ŠKODA FABIA Rally2 competition special, based on the latest, fourth generation of the popular ŠKODA FABIA production model, will soon be going on sale. The developers at ŠKODA Motorsport are currently finalising the car and preparing for its homologation and first deployment in competition. In our interview, Aleš Rada, Head of Racing Car Engineering at ŠKODA Motorsport, explains how the development of this kind of car takes place, what rules govern it and what pitfalls the engineers have to be wary of.

When does the development of a rally car begin, and how is the start of development linked to the development of mass-produced cars? 
If we are talking about the development of a racing car according to the rules for the Rally2 category, the condition is that the racing car must be based on a production model. It follows that it is necessary to build on the development work done by our colleagues in production development on a real production car. In the past, we have started the development of a competition car at different times in the development of a production car. For some of our specials we started when the production car had already existed for some time, for others we started at a stage when everything about the production car was still secret. 

What about the latest rally car?
In its case, we started development before the coronavirus pandemic began, long before the world premiere of the new FABIA last year. The project and communication plan is that we will launch the race car about a year after the world premiere of the production car. This is an ideal interval to take advantage of the fact that the fourth-generation FABIA is still a new car and we can follow up and launch the racing special in a “sporty” way.

Aleš Rada, Head of Racing Car Engineering at ŠKODA Motorsport

Did the pandemic slow down your development work?
It’s true that we had to change the way we work a bit. Basically, for one whole year of development we worked on the car almost exclusively from home: all the work was done in a digital environment and we couldn’t build prototypes, for example. We really did a huge amount of work in the virtual environment and we’ve made a lot of progress in the use of different simulations and other digital tools compared to our previous cars. So we did more virtual development work and thorough testing on the computers than we did for any of its predecessors. 

What are the various phases in racing car development?
The phases aren’t that different from production car development. At the beginning there is a certain vision, an idea of why the car is being made, what category it should belong to and what model it should be based on. For us, it has long been the FABIA model, because it’s a compact car that matches rally car requirements most closely in the carmaker’s portfolio. In the next phase, we need to evaluate the production car’s potential in terms of its “transformation” into a racing special. We have to decide what we expect from the car and its various parts, what we expect from the chassis, engine, transmissions and other structural sections, for example. We make a performance balance sheet, in which we naturally aim for the top of the category. We know what the current car is, we know roughly what the competition will come up with for the next season and we try to adapt to that so we’re always at the forefront. This balance gives rise to the definition or concept of the car, which we then start to design in line with that. First we create the complete construction data in the computers, then we do various numerical simulations, aerodynamics calculations, strength calculations, cooling simulations and so on.

The new rally car is based on the fourth-generation mass-produced ŠKODA FABIA.

And does the prototype come next?
Yes, next we build the prototypes, and in the case of the new car we started with two test cars. This is followed by practical testing, either of the individual components or of the car as a whole. We do this testing both in our labs, for example in the wind tunnel, and then we take it out for test drives. These always show us what we can improve or possibly redesign. The schedule is such that we always want to complete about two design cycles. This means that if there are any problems, we can rebuild the part and put it through the full tests again. When we finish the car in this way, the next stage is homologation and the car’s technical status is essentially frozen for the most part. Then we can just tune and adjust the car for different surfaces, i.e. different types of asphalt, gravel and snow. The development “joker” system gives us the opportunity to change some parts during the homologation period. The current system is such that a maximum of 5 “jokers” can be applied in the first two years after homologation. In the second 24 months we have 5 jokers available as a package (i.e. they have to be implemented at the same time), plus 2 additional jokers.

How do the rules constrain the development process?
The rules are strict. For example, the body of the race car must be identical to that of the production car – the only exception is the possibility of extending the car with mudguards and bumpers, and we can also build a tunnel into the floor to accommodate a 4×4 drive system. The front and rear axle of the race car must be the McPherson type. The chassis parts are completely our own design and have nothing to do with the production car. The same goes for the gearbox. The engine, on the other hand, must be based on the production unit. In this case, though, it may be an engine from another production car made by Volkswagen.  For the Rally2 category, the engine’s maximum capacity is 1.6 litres.

Testing the still-disguised ŠKODA FABIA Rally2

Are there any financial limits that apply to development?
Basically, we are only limited by our budget. The rules don’t cover anything like that, so there is no financial ceiling. But there is a financial cap on the price of a race car. In order to offer the car to customers, we have to adhere to a strict financial cap on the maximum price of the car in the “ready-to-race” specification. This term means that the car complies with all the rules (safety, technical, sporting) required to run the car in an asphalt event. The limit also applies to the price of certain important spare parts. FIA actually checks invoices and payments. In practice, we offer our customers solutions or parts in addition to these basic specifications. These, for example, increase crew comfort by adapting the interior to individual needs, or increase the car’s resistance to wear and tear etc. These are optional extras at extra cost.

Does the new car give you the chance to make any revolutionary changes?
The rules for our category have been in place since 2012. As far as various technical solutions are concerned, there is very limited space for revolutionary changes or inventions. Developing a race car according to the rules is mostly about looking for details and ways to get more out of the car, and basically you’re always asymptotically approaching a certain theoretical performance maximum. The new model gives us a chance to make bigger changes and gives us a chance to take advantage of some of the new features of the production car.

What features are those in the case of the new FABIA?
The new FABIA has a longer wheelbase than the previous generation and the production car is a little wider, which allows us to work with the interior layout, which can affect the centre of gravity, weight distribution between the front and rear axles etc. The body is mainly made of high-strength sheet metal, which in our case has a positive effect on the body’s stiffness and therefore the car’s handling and also the safety of the crew. We also have a larger engine compartment, which has an effect on the positioning of the power unit and has influenced the design of the gearbox, for example. But the car also has a larger front, for example, which we have to work within terms of aerodynamics to achieve the necessary aerodynamic efficiency, i.e. maximum downforce and minimum frontal drag.

How helpful is your past experience when you develop a new car?
Very. One of my favourite sayings is that personal experience is non-transferable. And we have gained a lot of experience since the development of the FABIA WRC, which was based on the first-generation FABIA. The previous car is always a source of a lot of information: we know its strengths and weaknesses, and with the new one we always work to eliminate those weaknesses. So when we develop a car, we draw on several sources: the production model and our experience with the previous car, but of course we also look around at what the competition is doing. In the past, we have often taken inspiration from them in certain design details, and we are delighted to now see our ideas in cars recently rolled out by our competitors. Racing car development is essentially the summit of car development, so it’s good to keep our eyes open so that we keep improving and don’t get left behind.

ŠKODA FABIA WRC (2003)

Where is there room for creativity when you’re developing a new car?
Although the rules set many strict limits, on the other hand there is of course room for various creative solutions. Take weight, for example. There is a strict minimum weight limit, but it’s up to us how we distribute that weight in the car. Whether that means weight distribution between the axles, or positioning in terms of the height of the centre of gravity. Of course, we want to keep the centre of gravity as low as possible, and we use what we call “rails” – parts that protect the underside of the car. The heavier these rails can be, the better for us, actually. We also address weight distribution in terms of inertia around the vertical axis of the car. This affects the car’s handling and stability, for example. When the weight is far away from the axis and has a large moment of inertia, the car is more stable, but this can negatively affect the speed of the car’s response to steering wheel impulses. These characteristics are then reflected in the calibration of other parts such as dampers, springs, stabilisers and differentials. This actually brings us to other topics of technical creativity. Theoretically, there are an infinite number of options for shock absorbers, differentials and springs.

Do you collaborate with other ŠKODA departments when you’re developing a rally car?
Yes, a lot. We collaborate with all departments of ŠKODA Technical Development, but also with the quality department, marketing, production and other departments of the company. We do some of the development work ourselves, but our colleagues in production development help us intensively with many things. Since the beginning of the project, we have been in close contact with the design department. Our engineers also build on the work of our colleagues who created the production body. Production development also helps us with a number of simulations and calculations in the area of body design and construction. We work with the aerodynamics engineers from the series production to optimise the racing car’s drag. Our colleagues in electronics development also help us. Our engine development makes intensive use of findings and experience from mass-production engine development. In this way we’ve been successfully collaborating with our colleagues in mass-production engine development for more than 10 years. The bodywork for the test cars is built for us by the prototype construction department, which also builds prototypes of production cars. The technical conformity department helps us meet some of the legislative and homologation requirements. There is a lot of cooperation, and I apologise to any colleagues I haven’t mentioned. What’s more, we share know-how across Volkswagen Group.

And how can you help in the development of production cars?
One way we can help is by sharing our experience, so our production development engineers can learn new things and broaden their horizons. In fact, we have engineers from production car development working with us on some projects. After all, the main difference between the development of a production car and a race car is the time and number of people involved. In production development, there is usually a longer development cycle and the development team is much bigger than in our motorsport department. That makes our environment interesting for our mass-production colleagues because of its complexity and the fact that they get experience in slightly different conditions than they’re used to.