3.3. In respect of Art. 3.2 above it is permitted to make the following modifications to effect installation: a. Alternative engine mountings, sump pan and exhaust manifolds. b. Relocation of ancillaries such as alternators and steering pumps. c.
To change the orientation of the otherwise unmodified inlet manifold provided it is fitted directly to the cylinder head without the addition of an intermediate adapter device.
3.4. For diesel and petrol engines under 1500cc actual capacity forced induction is permitted providing that the complete original induction system is retained unmodified other than the replacement of the air filter element.
3.5. Fuel injection may be fitted where it was standard equipment by the manufacturer for that engine type and where the original plenum chamber and throttle body is retained for that engine type.
3.6. A standard Wankel unit will be considered as three cylinders. Twin Wankel units are prohibited.
3.7. Engines must comply with the silencing Noise levels and have induction air filter elements fitted that ensure the vehicle complies with noise regulations.
3.8. Only H shift pattern manual transmissions are permitted. The gear lever must remain the only means of changing gear unless an alternative method was originally fitted by the vehicle manufacturer as standard. Automatic transmissions are permitted provided that they are in their original configuration as fitted by the manufacturer to that specific Vehicle model.
3.9. The number and location of the driven wheels must remain as original to the model of Vehicle.
4. Wheels and Tyres 4.1. Wheels and tyre sizes are free but must fit within the standard unmodified wheel arch. 4.2. Vehicles must be fitted with tyres that are always legal for use on the Public Highway. 4.3. Tyres must comply with Chapter 8 App. 4 Arts. 2 – 3
4.4. Vehicles must have all spare wheels securely fastened in position and must not be fitted with spiked or studded tyres or any non-skid attachments other than chains if permitted by the Official Documents.
5. Electrical Systems
5.1. Vehicles must have a maximum of four forward facing beams as well as side and indicator lights unless further restrictions are specified in the Official Documents.
5.2. Light pods are not permitted. 5.3. A headlamp must provide the main beam and dipped beam functions.
5.4. An auxiliary lamp provides a beam other than that provided by the headlamp. With the exception of cars built before 31st December 1946 the maximum width of the lamp body of any auxiliary lamp must not exceed 222mm.
5.5. A headlamp may consist of a single reflector with a dual filament bulb or separate reflectors each with single filament bulbs providing the functions of main beam and dipped beam separately. This will be considered as equivalent to a single dual filament headlamp unit. Lamp units comprising two reflectors where one is fitted with a dual filament bulb will be considered as a combined headlamp and auxiliary lamp. In this instance therefore no additional auxiliary lamps may be fitted.
5.6. Auxiliary lamps unless fitted by the manufacturer as standard equipment using gas discharge or LED technology are not permitted and gas discharge or LED headlamp units may not be retro-fitted.
5.7. Auxiliary lights must not be used in neutral Sections except in poor visibility as permitted by law.
5.8. Where more than four beams are fitted as standard only four may be used and the remainder must be rendered unusable for the duration of the Event.
5.9. Vehicles must have all lights fitted and used according to Motor Vehicle Lighting Regulations.
Motorsport UK 2025 National Competition Rules Version 11
Chapter 13 Appendix 15- Technical Regulations- Road, Endurance and Historic Road Rally Cars
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