Groups
In FIA automobile sports, group N describes a very specific processing stage for passenger cars from the 1980s to the present day.
Processing stage and provisions
These processing levels have been classified by the FIA - namely according to group N, A, B etc. Of these groups, group N is the "mildest" tuning level. In the next free group A, all series parts can be processed. That means that in the Gr. N all changes not expressly permitted by these regulations are prohibited. The external appearance of the vehicles also remains unchanged. The fenders must not be modified. The replacement of shock absorbers and springs on the chassis is permitted with certain restrictions.
The technical starting data are in the group A and N homologation sheets . The individual regulations for group N are in Article 254 of the ISG of the FIA . The forerunner of group N was group 1 described in the previous regulations .
The provisions of group N are only applicable to production vehicles that must have 4 seats. The minimum quantity is 2,500 units in 12 calendar months. Delivery variants (VN) of group A ( touring cars ) also apply to group N (production cars ). Equipment variants (VO) of group A do not apply to group N, exceptions see catalog in the link below.
Displacement classes
Within group N, the vehicles are divided into cubic capacity classes. Classes are common today
- up to 1400 cm³
- over 1400 to 1600 cm³
- over 1600 to 2000 cm³
- over 2000 to 3000 cm³
- over 3000 cm³
In earlier years, up to around 1980, it was also common to subdivide the class up to 1400 cm³. The engine capacity limits were 700, 850, 1000, 1150 and 1300 cm³. Because of the minimum number of items described above, z. B. Carlo Abarth's cars are not homologated in the next-series class.
Period of validity of the homologation
Group N homologation is carried out by the vehicle manufacturer at the FIA and, if necessary, extended depending on the manufacturing time of the type and other marketing and cost considerations. The manufacturer is also applying for so-called supplements to the original homologation sheet, which describe subsequent equipment variants and should be carried in full with the homologation documents and the car pass to racing events.
After the validity of the homologation has expired, the homologations for vehicles in groups N and A for the DMSB area are automatically extended by 3 years (groups DN and DA). The currently valid technical regulations of group A and group N apply. The national group A and N homologations are valid in the entire DMSB area, with the exception of competitions with FIA rating. A current list of the currently valid homologations and terms is available on the DMSB website.
After the DN homologation has expired, a Group N vehicle must either switch to an "open class" such as Group H or, for example, according to the new regulations created by the DMSB 2006 in Division 6 of the historical CTC / CGT (Classic Touring Cars / Classic GT) (valid for Group N for years of construction 1982 up to and including 1996).
These regulations are intended to enable the start of touring cars and GT vehicles as they were in use between 1966 and 1996 (expiry of the DA and N homologation). Touring cars and GT vehicles that were FIA homologated between 1966 and 1996, including in groups 1, 2, 3, 4, 5, N, A or B, are permitted (see Article 2). The vehicles must comply with the FIA regulations of the time and the following provisions, which have priority.
Weight
The N homologation sheet specifies a minimum weight under No. 201. This must be observed under all circumstances and is preferably checked during the racing breaks. Ballast may be used; this must be declared and sealed. The vehicle is measured "as it is", i.e. with the current level of all liquids, but without the driver, helmet, etc.
Excluded parts
- Clutch disc
- Suspension springs with restrictions
- Shock absorbers with restrictions: the number must not be changed
- Wheel bolts and nuts
- Rims ; However, these must correspond to the dimensions of the homologation sheet
- Tires; Restrictions possible depending on the event
- Brake pads , hydraulic handbrake
- Seats; This series must comply or a separate, time-limited homologation have
- Fuel tank; this is then subject to strict safety regulations
- Petrol and hydraulic lines
- all accessories that have no influence on driving behavior, i.e. radio, sunroof, lighting, steering wheel, the exhaust system depending on the tender . Restrictions regarding noise emissions are possible, depending on the event, e.g. B. at rallies according to the StVZO .
Allowed changes
Any editing that is not expressly permitted is prohibited. Defective parts may only be replaced with original parts. This can create a conflict when the camshaft is replaced. Nobody at the racetrack can check whether it was really defective, as defective parts are almost always disposed of.
Camshaft, exhaust and engine control
The new camshaft to be installed is described with a certain degree of accuracy in the Group N homologation sheet . The art of the engine tuner now lies in finding a camshaft that corresponds to these mechanical dimensions, but can achieve more power.
In this context it is important that (almost always) the exhaust system is free, and the microprocessor in the electric motor control. By fine-tuning with many test bench runs, these three variables (camshaft, control system, exhaust system) increase the engine's performance by 10 to 20 percent, in extreme cases even more. The sound of the engine is often very revealing. Stronger increases are possible with supercharged engines, since the boost pressure is regulated directly by the engine management system. Today it is sufficient to change the characteristic fields in the control unit (ECU mapping) to change the characteristics of the engine from high-speed to powerful. Mainly properties such as ignition timing and AFR maps (air / fuel mixture) as well as the maximum boost pressure depending on the engine load and speed ("Turbo Dynamics Table", only for vehicles with exhaust gas turbocharging) are adapted. In previous years it was necessary to change the camshaft. When the exhaust gas temperature rises, this also entails adjustments to the valves and pistons.
Springs and shock absorbers
Coilovers are allowed. This means that a certain lowering is possible. The dimension no. 205 specified in the N homologation sheet: "Minimum height between wheel hub and wheel arch" must be adhered to within the scope of the tolerances .
Street legal
A car of group N can be registered with restrictions. The TÜV technical limit criterion is the sound level that is measured under test conditions (not at maximum or nominal speed, but sometimes significantly below). In later operation at higher speeds, the nominal level will definitely be exceeded.
General road use on so-called slicks, i.e. racing tires , is not permitted , which is why tire / rim sets are transported as luggage or the drivers use semi-slicks (with the EU-wide ECE test mark). In addition, the driving comfort is limited and the noise, not just from the exhaust, can be annoying. Nevertheless, there are mainly participants in the automobile slalom who come to the event on their own. Usually financial reasons are decisive (trailer and towing vehicle are not required), but the speed of the journey is also significantly higher than with a team.