(d) This clause applies to In-line 4 & 6 cylinder engines. (i) The OEM manifold that is standard for the engine must be used. (ii) No material of any kind may be added or removed from the interior or exterior of the OEM manifold. Except that material may be removed from directly below restrictor plate hole. (iii) Where a carburettor type manifold or central throttle body injection manifold is used that is not fitted with the original carburettor, an adapter plate must be used. (iv) This, one only adapter plate, must not exceed 35mm in height including gaskets and restrictor plate. (v) The inlet tract of the carburettor - adapter plate - restrictor plate must be in one vertical plane. (e) This clause applies to in-line 6-cylinder OEM multi-point EFI manifold. The EFI throttle body must be removed. A right angle adapter assembly with 60mm radius and a downdraft carburettor must be used. The base face edge of the carburettor must be no more than 100mm from the top of the inlet port. This adaptor measurement must include the thickness of the restrictor plate. T12-2-19 Exhaust (a) A standard cast iron exhaust manifold must be used in its OEM form. It may be fitted in any configuration, as long as the manifold and head surface is not modified. (b) The following modifications are not permitted:(i) Standard exhaust manifold may not be of two front (or rear) halves. (ii) No extractors permitted. (c) Mufflers are free, however sound levels must comply with Rule S3. (d) Exhaust pipes must discharge towards the rear, or underneath the car. (e) Side-mounted exhaust systems inside or outside the body, must be suitably guarded where they pass the driver, to enable first aid personnel to get driver out of the car without getting themselves burnt. T12-2-20 Carburettor (a) The engine shall be normally aspirated only, and fitted with one carburettor only. (b) The carburettor must be of down draft design. (c) The said carburettor shall have a maximum of four chokes, and the use of fuel injection, supercharging and turbo charging is prohibited. (d) Glass bowls must not be fitted on carburettors or fuel pumps. Two throttle return springs must be fitted to the carburettor shaft linkages. (e) Plastic fuel pump and plastic fuel line fittings and plastic pump bases are not permitted. T12-2-21 Restrictor Plate (a) A restrictor plate with an internal circular hole of 42mm diameter must be fitted between the inlet manifold and the carburettor base or between inlet manifold and adapter plate. (b) Restrictor plate to be SNZ approved 2001 version. Restrictor plate to be available from tracks and must be used at all times. (c) The internal hole of the restrictor plate must not be modified in any way. The restrictor plate must not be modified in any way. T12-2-22 Adapter Plate, Acceptor Plate (a) The adapter plate must be detachable from both manifold and carburettor.
2010 ELECTRONIC RULEBOOK
2010 NZ Speedway Rule Book