13.2. Permitted Modifications
13.2.1. Other than as detailed no other modifications are permitted:
13.3. Engine
a. Any FIA / ASN approved / homologated safety equipment may be installed. b. Brake friction material may be uprated.
13.3.1. Forced induction equivalence 1.7.
13.4. Wheels and tyres
13.4.1. Standard wheels and tyres from Ch. 8 App. 4 List 1A only may be used.
14. Regulations for Road Cars 14.1. Description
14.1.1. Road Cars- Series Production: Saloons and Sports Cars produced in quantities of not less than 1000 per annum.
14.1.2. Road Cars- Specialist Production Cars with a minimum annual production of 20 Chassis which do not qualify as Series Production Cars.
14.1.3. Road Cars – Electrified Series Production,- Standard Electrified Saloons and Sports Cars in quantities of not less than 1000 per annum, compliant with Ch. 7 App. 11 Art. 1.9.
14.2. Vehicles must compete in an Event in a road legal condition as defined in Art. 12. 14.3. Chassis
14.3.1. Must conform to the Manufacturer’ s original chassis structure and specification of construction dimensions and material. Roll cages must not accept or assist any direct suspension loads.
14.4. Body( including aerodynamics)
14.4.1. Silhouette of the Vehicle must remain unaltered in construction dimension and material. The silhouette will be taken in the condition in which the Vehicle competes( convertible closed cars competing with the hood or top not erected shall have the silhouette determined in that condition).
14.4.2. Engine bonnet / cover and luggage / boot cover may be replaced with an alternative material. 14.4.3. Laminated windscreens permitted but all other glass may not be replaced by another material. 14.4.4. Interior trim must remain fitted( except floor carpets / mats).
14.4.5. All working equipment fitted as standard( heater window mechanisms sunroof door handles) must be operable at all times.
14.5. Engines / Motors
14.5.1. For Road Cars – Series Production: the cylinder block and cylinder head must remain in the original position and be externally identifiable as that fitted to the original model or specified option. Induction is free as are exhaust systems.
14.5.2. For Road Cars – Specialist Production: the cylinder block and head must be of a make and type produced in at least 1000 identical units originally available through the normal commercial channels of a land vehicle manufacturer.
14.5.3. Must be capable of being started from an onboard power source operable by the Driver when seated normally.
Motorsport UK National Competition Rules 2026 Edition 1
Chapter 14 Appendix 4- Technical Regulations 540