SDMA Class Descriptions

Updated descriptions as approved by Committee 10.10.2024

The SDMA Road and Race Classes have been developed in consideration and with guidance from the Motorsport Australia Manual of Motorsport. Generally, the Classes have been designed to place like style of vehicle with like style.

No attempt has been made to provide any equality of performance other than by the modifications listed within the subdivision of each Class and their engine Capacity groups. The intended groupings take precedent over any perceived or individually interpreted placement of a vehicle in a class by a competitor.

The “Road" classes are intended for vehicles that are, or could be registered with little or no changes required to the vehicle from the condition it is presented in on the day for competition regardless of the modifications allowed for in each Class.

Road registered vehicles include the ACT's Concessional Registration Scheme (CRS) for Veteran, Vintage and Historic (including Modified Historic) vehicles and the NSW's Conditional Registration under the Historic Vehicle Scheme (HVS) and the Classic Vehicle Scheme (CVS). 

Note: Rally registration is NOT included and rally vehicles will be 'Track" classified based on their modification level.

Classes A - E for Road Registered/Registerable Vehicles must use road tyres – See Note a) for definition of road tyre

Vehicles classed as “Exotic” by the Motorsport Australia definition (i.e. purchase price – see here) are NOT eligible for Classes A -D

Class A Road - 2WD

For stock standard production vehicles, (Defined by Motorsports Australia (MA) as mass produced touring cars commercially available to the general public) with full production trim and standard seats. Includes HSV and FPV style factory vehicles. Vehicles must be either road registered or of an equivalent standard.

Roll cages are NOT permitted in SDMA Road classes, however rollover protection for convertible vehicles is recommended as long as it not designed to improve chassis rigidity (e.g. By being connected/welded to suspension towers etc).

Permitted Modifications:

  • Decorative additions only such as exhaust tip or body kit.

  • Air Cleaner is free.

  • Exhaust is free – subject to noise restraints.

  • Wheels and tyre sizes may be changed, provided they retain commercially available treaded road type tyres (see note a) and fit within the standard guards with appropriate clearances. The scrutineers will assess acceptable tread depth in accordance with the relevant MA NCRs .

  • Springs, shock absorbers and anti-roll bars may be changed provided they remain road legal and use original chassis mounting points. Camber adjustment devices may be used.

  • Driver’s seat may be replaced with a sports type seat.

Capacity Classes*:

  • 0 to 1600cc

  • 1601 to 2000cc

  • 2001 to 3000cc

  • over 3000cc

Notes:

(i) No change is permitted to the intake system (e.g. to carburettor, throttle body, fuel injection, intercooler, turbo/supercharger boost or by modification or replacement of the factory Engine Control Unit). The factory ECU must be retained unmodified.

(ii) No change is permitted to the engine or transmission control, i.e. the factory engine and transmission ECU’s must be retained unmodified.

(iii) The engine and /or the transmission ECU’s can NOT be supplemented by the addition of “piggy-back” boards or similar.

(iv) Adjustable spring platforms or coilovers may NOT be used - unless fitted as standard equipment by the Manufacturer.

(v) Due to the obvious difficulty in determining ECU status at scrutineering, the organisers reserve the right to insist on documented proof that boost and ECU remain standard. This may involve the entrant providing a Statutory Declaration from a recognised engine tuner before being allowed to compete.

Class B Road - 2WD

For production vehicles as described in Class A above, with further modifications allowed as detailed below. Must be of a standard basically suitable for registration.

Must retain full glass and must not use (non-standard) lightweight panels. However, at the organiser’s discretion, replacement bonnets and boots of a decorative nature (e.g. composite construction) may be used but only if the replacement panels are mounted and operated using factory hinges/latches.

Roll cages are NOT permitted in SDMA Road classes, however rollover protection for convertible vehicles is recommended as long as it not designed to improve chassis rigidity (e.g. By being connected/welded to suspension towers etc).

Permitted Modifications:

  • Rear seats and carpet may be removed but all other production interior trim (dash, door trims and window winders etc) must be retained.

  • Intake system is free (including turbo/super charging, multiple carburettors, increased turbo boost, intercooler etc).

  • Guards may be slightly flared in metal or with add-on composite or rubber flares suitable for registration purposes.

  • Engine must be from the original manufacturer and fitted with little or no modification to the firewall (e.g. SR20 in Datsun 1200, 13B turbo in early RX7, Gen3 in early Commodore). Note: The original number of rotors/cylinders, available new from the Manufacturer, must be retained and engine must be in the original location.

  • Brakes are free.

  • Battery (including location) is free.

  • Engine Control Unit is free.

  • Coilovers and adjustable spring platforms are permitted.

Capacity Classes*:

  • 0 to 1600cc

  • 1601 to 2000cc

  • 2001 to 3000cc

  • Over 3000cc

Class C Road - AWD

For All Wheel Drive (AWD) production cars (e.g. Subaru, Mitsubishi, VW, Nissan, Toyota etc).

Permitted modifications for Class C Road - AWD cars are as detailed earlier in this document for Class A Road - 2WD Level 1.

Roll cages are NOT permitted in SDMA Road classes, however rollover protection for convertible vehicles is recommended as long as it not designed to improve chassis rigidity (e.g. By being connected/welded to suspension towers etc).

Capacity Classes*:

  • 0 to 1600cc

  • 1601 to 2000cc

  • 2001 to 3000cc

  • Over 3000cc

Class D Road - AWD

For All Wheel Drive (AWD) production cars (e.g. Subaru, Mitsubishi, VW, Nissan, Toyota etc).

Permitted modifications for Class D Road- AWD cars are as detailed earlier in this document for Class B Road - 2WD.

Roll cages are NOT permitted in SDMA Road classes, however rollover protection for convertible vehicles is recommended as long as it not designed to improve chassis rigidity (e.g. By being connected/welded to suspension towers etc).

Capacity Classes*:

  • 0 to 1600cc

  • 1601 to 2000cc

  • 2001 to 3000cc

  • Over 3000cc

Class E Road - Special vehicles

This includes:

  • Kit cars (e.g. Ultima, AC Cobra replica, Locost, Clubman* etc), and

  • other special compliance cars (including individually engineered)

  • 2WD and AWD.

*Clubman means a lightweight two-seater open-top sports car generally based on the Lotus Seven.

Vehicles must be either road registered or of an essentially equivalent standard and use commercially available treaded road type tyres (see note a).

Permitted Modifications:

  • Any

Capacity Classes*:

  • 0 to 1600cc

  • 1601 to 2000cc

  • 2001 to 3000cc

  • Over 3000cc

Class F Track - racing Sedans

For production based, two wheel drive vehicles, which have been extensively modified beyond suitability for registration. (i.e. vehicles that would fit or be classified within Motorsport Australia’s 3rd Category automobiles. The 3rd Category provides for Touring Cars and includes but is not limited to: Sports Sedan, Series Production, Circuit Excel, HQ Holden, Improved Production, and Saloon Cars).

In addition to Classes A - E, the following modifications are permissible.

Permitted Modifications:

  • Engine may be from any manufacturer but must be a production based item (i.e. specialist “racing only” engines such as F1 Ilmor are not permitted).

  • Engine may be relocated for weight distribution purposes.

  • Firewall may be modified to allow engine fitment.

  • The engine and transmission layout is free.

  • Interior may be stripped and modified.

  • Roll cages are permitted and can be connected/welded to suspension towers.

  • Lightweight components, panels and non-glass windows may be used.

  • Guards may be extensively widened/flared to allow fitment of larger wheels/tyres Racing tyres including slicks or wets may be used.

  • Suspension modifications are free.

  • Window Nets (as specified by TECHNICAL APPENDIX Schedule I – Safety Harnesses and Window Nets in the Motorsport Australia Manual) are highly recommended for Class F vehicles.

Capacity Classes*:

  • 0 to 1600cc

  • 1601 to 2000cc

  • 2001 to 3000cc

  • Over 3000cc

Class G Track - Sports Racing

Closed Wheel Sports Racing cars, and Group A type Sportscars. (NOTE: This class can include any AWD vehicles deemed unsuitable for Classes C – E AWD and SV).

(i.e. vehicles that would fit or be classified within Motorsport Australia 2nd Category automobiles. The 2nd Category provides for two-seater sports racing automobiles and other highly-modified cars and includes but is not limited to: Group 2A Sports Cars, open and closed, Group 2B Prodsports, Group 2C Supersports, Group 2F Prodsports).

List of 2nd Category Eligible automobiles

Permitted Modifications:

  • Any.

Capacity Classes*:

  • 0 to 750cc

  • 751 to 1300cc

  • 1301 to 2000cc

  • Over 2000cc

Class H Track - Open Wheeler

For Open Wheel racing cars.

(i.e. vehicles that would fit or be classified within Motorsport Australia 1st Category automobiles. The 1st Category provides for Automobiles offering accommodation for one person, and designed exclusively for races and speed events on a closed course and includes but is not limited to: Formula Ford, Formula Ford 1600, Formula Vee, Free Formula).

Permitted Modifications:

  • Any.

Capacity Classes*:

  • 0 to 750cc

  • 751 to 1300cc

  • 1301 to 2000cc

  • Over 2000cc

NOTES

*In addition to the above class capacity rules, multipliers apply to Rotary Engines and Turbo/Supercharged engines to calculate effective capacity for classification purposes:

  • Turbo/supercharged have the engine capacity multiplied by 1.7. For Diesel multiply by 1.5. 

  • Rotaries have the engine capacity multiplied by 1.8.

  • Turbo/supercharged rotaries have the engine capacity multiplied by 1.8 then 1.7 (net multiplier equals 3.06)

Examples:

  • 2 litre motor with a turbo/supercharger is 2000cc x 1.7 = 3400cc.

  • 13B rotary is 1308cc x 1.8 = 2354.4cc

  • 13B rotary with a turbo/supercharger is 1308cc x 1.8 x 1.7 = 4002.48cc

a) “Road tyres” must be commercially available and do NOT include Racing tyres (including slicks or wets) specifically marked as being illegal or unsafe/unsuitable for road use, such as: “For Racing Only” or “Not for Highway Use”. It should be noted that, Nitto uses a term “Recommended for competition use only”. This is not considered by SDMA to be a specific exclusion from road use.

b) All vehicles must be entered in the first class that they comply with. i.e. if a car complies with the Class A requirements it must be entered as Class A and cannot be entered in Class B, C, D, E, F, G or H.

In addition to the forgoing Competition Classifications and Capacity Classes, SDMA reserves the right to reclassify a vehicle and/or to introduce additional classes if it is considered warranted.

It is the competitor’s responsibility to provide all required evidence to support a vehicle being entered in a class contrary to that determined by the SDMA Committee (or it’s delegated officer).