Development of the ŠKODA FABIA R5 engine
The development of the ŠKODA FABIA R5s power unit has evolved since the ŠKODA Motorsport team decided to enter the R5 category. The rules at the time did not allow the use of anything other than a mass-produced 1.6-liter turbocharged engine, which is still not part of the Volkswagen combine’s portfolio of power units.
First of all, we tried to change these rules. But fortunately, under the new rules, it was permitted for the engine capacity to change. Subsequently, ŠKODA Motorsport’sengine experts compared the advantages and disadvantages of the various VW engines for their usability in the R5 category. They chose the 1.8-liter, 123 kW EA 888 engine, produced in Shanghai, China.
At that point, work on defining basic thermodynamic quantities could begin (stroke, drilling, size and shape of intake and exhaust channels, timing…). The first prototypes were built and a number of optimisations were done to ensure maximum performance, reliability and the pricing for both manufacturer and customer rally teams to use the engine in rallies. Engine homologation was made on April 1, 2015, along with homologation of the entire car.
|Turbocharged 4-cylinder||1,620 cm3|
|Max. power||205 kW|
|Max. torque||420 Nm|
From a mass-produced engine to a racing one
The mass-produced engine, from which the racing engine of the ŠKODA FABIA R5 is derived, was originally introduced in the Volkswagen Lamando and ŠKODA Superb cars for the Chinese market.
In comparison to the mass-produced version, the engine in the rally car is different in the following ways:
- Due to the reduction from 1.8 l to 1.6 l, there is a completely new crank mechanism, specially developed for rally conditions
- The valve distribution and cylinder replacement system has been completely redesigned in order to ensure ideal conditions for replacement and cylinder filling
- The fuel system (high-pressure pump and injection nozzles) was also adjusted
- The racing engine is equipped with a modified turbocharger from the Audi S3 to ensure the necessary supply of air
- Due to the new engine position in the car, the oil system and the engine ventilation system have been completely redesigned and optimised
Such an engine in rallying must be reliably controlled and therefore a special engine control system has been developed to provide, in addition to performance parameters, reliability in case of the failure of some electrical Components.
|Manual sequential shifting|
|Mechanical differentials (front and rear)|
The ŠKODA FABIA R5 has four-wheel drive. The 4×4 drive is designed with 2 axle differentials. The front one is located in the same place as the gearbox. The rear transmission is connected to the gearbox by a Cardan shaft. The car does not have an inter-axle differential. However, for the correct operation of the handbrake, a disconnecting clutch is needed, which disconnects the front and rear axles when pulling the handbrake. The Differentials are mechanical and self-locking with no electronics.
A 5-speed gearbox and up to 200 km/h
The ŠKODA FABIA R5 has a 5-speed, sequential, manual gearbox. The maximum speed is derived from gear selections with the overall maximum speed being around 200 km / h. A rally driver is able to change gear in tens of milliseconds.
|Front and rear||McPherson|
|Brake discs for tarmac||Ø 355 mm / width 32 mm|
|Brake discs for garvel||Ø 300 mm / width 32 mm|
Both axles have a McPherson suspension designed for extreme conditions that cannot occur in regular traffic. On jumps, the force on every wheel equals to multiple of the weight of the car.
Although it is important to be fastest at a rally, at certain times you need be able to slow down too. Even breaking has its own specifics and therefore the brake discs have different diameters for different surfaces.
Tarmac: Front 355 mm + Rear 300 mm; Gravel: Front and rear 300 mm.
The difference is down to the ability of the tyre on a given surface to transmit forces between the vehicle and the road surface. As this ability is greater on asphalt, larger brake discs can be used for tarmac surfaces. In the rules, the use of larger asphalt wheels is also allowed with the prescribed 18 ”disc while a 15” disc is prescribed for the gravel.
Different surfaces do not only mean a change in the use of brake discs. In view of the greater roughness of the gravel, the clearance height of the car for this surface is several tens of millimetres higher.
There are also other parts, used only for a given type of surface (e.g. wheels, dampers, springs, brakes), and adapted for surface specificities (e.g. spring stiffness, shock absorber characteristics, stabiliser stiffness, etc.)
A pure rally car without electronic assistance
The ŠKODA FABIA R5 does not have any auxiliary electronics for driving. Of all possible sensors, the car only has the sensors required for engine control and sensors for brake pressure, steering wheel position or fuel level – but these are not related to the engine control and are to provide information only. As the name of the engine sensors suggests – their signal is used by the engine control unit to properly control the engine during its operation in all driving modes and under different atmospheric conditions.
What fuel does ŠKODA FABIA R5 use?
The ŠKODA FABIA R5 needs special racing fuel developed directly for rally cars under FIA compliance conditions. Some rallies require explicitly prescribed fuels and others do not. For this reason, we offer guides to almost twenty different fuels so our customers can choose the optimal fuel for their races.
To store fuel, the car has a special fuel tank according to the FIA regulations. It is made of Kevlar fabric and puncture resistant rubber. The tank is filled with a special foam to prevent spilling of gasoline. From the bottom, the tank is protected by a glass-kevlar fibre cover and an absorbent layer. The cover has a minimum thickness of 10 mm according to FIA regulations.
The FABIA R5’s tank is filled thanks to a pair of quick couplings located directly on the top of the tank.
|Special Fuel Tank||Volume 82.5 l|
|Consumption||0.6 l / km of a special stage|