Maintenance of a Rally Car
Which are the most frequent mechanic breakages during a Rally?
On a track the engine is the most stressed organ, but during a rally it's the transmission to suffer the most. 80% of the mechanic jobs during a race are related to balance and trim. As concerns transmissions Skoda factory suggests to change it every 800 km of racing stages. Gears are very stressed and if you underestimate pitting you might occur in bigger issues. To be sure we change transmissions every 600 km of racing stages instead of 800, just in case. The same happens with brakes, we change brake pads every 400-500 km of racing stages. Disks reach 400°C (752°F) and the cast-iron tends to crack and you might even loose a wheel, especially in the descents. Cracks usually form in case of thermic shocks, so the cooling phase has to be done properly.
Which are the standard checks done in a rally assistance park?
Usually you have 40 minutes for car assistance. You make necessary changes and you control the tightness of the bolts. After that you check all the fluids, bleed the brakes and change wheels. And you get telemetry data. You have to be good at it. We ask the driver his feelings about the car, if he/she acknowledges something strange but you never have to rely only on the driver's impressions. Two years ago during a race a driver tells us that everything was fine with the car. Among our routine checks there's also transmission oil. We discovered some parts in the oil discovering a bearing breakage! Transmission oil saved the day and the driver didn't perceive anything with gear changing. However, I doubt he could have done one more Stage from the beginning to the end. It took 3 of us and a record time of 18 minutes to change all the transmission.
During rallies cars reach very high lubricating temperatures of the engine or of the turbocharger (in case there's one), after how long do you change the engine oil?
Manufacturers always give you reference parameters. For instance, Skoda imposes to change it every 200 km of racing stages. We change it every race and we revise the engines changing the worn parts every 800 km of racing stages for our Peugeot 207 Super 2000, every 2000 km for our Skoda Fabia R5 Turbo and every 2400 km for our Peugeot 208 R2. During engine revision, among other tests we use the dial bore gauge to measure cylinder ovalization. In this way we understand if the elastic piston ring is still holding on, preserving the engine's performance. For standard engines diameter tolerances are minimal (3-4 hundreds of a millimeter), while rally cars have wider tolerances since there should be less friction and components tend to dilate due to high temperatures. It's the OEM that establishes tolerances.
Which ignition and cooling procedures do you have to take into account after a racing stage?
Ignition procedure of a rally car is similar to a Formula 1 procedure. Before starting the engine you need to let the starter motor run without the control unit support. You need to make the oil pressurize in order to make it flow between crankshaft and bearings in the ignition phase. When the oil is pressurized you can start the engine. Every rally car should be warmed properly, always. By properly I mean warming the engine but also the transmission, the gears, the semi-axes joints and wheel bearings. Perfect functioning temperature of an engine oil is 90-100°C (194-212°F) and at least 60-70°C (140-158°F) for transmission oil. On the contrary when you finish a stage you have to cool the braking system down slowly. You need to drive for 5-10 minutes at 40-50 km/h so that all the car's parts could be back at normal working temperatures. For instance, Skoda Fabia R5 Turbo has a specific warning light that indicates the turbine's working temperature. If the light is red it means that temperature is above 150°C (302°F) and shutting it down now would mean to create a thermic shock. Aspirated engines don't have turbines but it is highly suggested to stabilize the engine at 90°C (194°F) before shutting it down anyway. The aim is to channel heat. Heat equals good functioning and good functioning equals power. Thermodynamically an engine's perfect temperature functioning is at 90°C (194°F).
At which working temperature do the brakes work on a rally car? Why is it not advisable to use a competition compound in a standard-use car?
As we mentioned before brake disks in rallies reach 400°C (752°F) and the compound of brake pads is made accordingly, to work with those high temperatures. If you use the same compound for the brake pads of a normal car the risk is that with lower temperatures brakes don't even work. Be careful with that!
Rally Forum: How to live a Rally Car Experience
Which kind of renting and assistance formulas does Autotecnica 2 offer to its customers?
We take care of mechanic assistance and logistics. Then the customer can choose to rent one of our cars or to bring his/her own car. By us you can rent: a Peugeot 208 R2B, a Citroen C2 R2B, a Renault Twingo R2B, a Peugeot 207 S2000 or a Skoda Fabia R5.
How much does it cost to rent a rally car for a race?
It depends on the formula you get. Let's make an example. If you rent the Peugeot 208 R2 for a national race of 60 km, it costs you between 3500-5000 € (depending if a wheel change is included or not) with a deductible of 6.000 €. In the market there are operators that sell the service below cost. How can they afford it? The answer is simple, they don't do all the regular maintenance checks and repairs, they don't revision the engine in due time, they make poor assistance to be short. For those people it's not important if the customer ends the race or not without mechanic issues. It's a totally different work ethic.
Which modifications are allowed for a car to stay in the homologation limits?
The answer here is not univocal everywhere. I can answer for what concerns Italian law. To be short and clear what you can modify is little or nothing. You can change the exhaust system with another homologated one. In that case my advice is to make an oil change every 10.000 km, but if the owner takes part to a few track days the interval should be reduced to 5.000 km. Remapping the control unit? It's not legal here, since you force the system to get horsepowers. Unfortunately - or luckily - if you want to have fun in safety you can do it. Taking part to real rallies and in that case we are there to take care of the mechanic part so the driver can focus on the rally only.
To contact Giuliano Inzadi and Autotecnica 2 click here.