Group ND Proposal
- Turbo charging is not permitted unless fitted as standard to the model.
- Turbocharger/s and associated inlet and exhaust manifold/s are free provided the compressor housing inlet diameter is no larger than the original standard turbocharger compressor wheel inducer diameter plus 10%.
- Twin turbochargers may be replaced by a single turbocharger configuration with an inlet cross sectional area no greater than the combined inlet cross sectional area of the standard twin turbochargers.
- Measurements for the compressor housing inlet diameter and cross sectional area shall be taken at the narrowest point of the inlet - within 1mm of the outermost face of the compressor wheel vane.
- The original turbocharger general location on the manifold (eg top or bottom mount) must remain.
- All other associated components including intercooler/s and boost controller/s are free, however each intercooler pipe (both to and from the intercooler) must only be used to channel air and no external bodywork alterations are made to accommodate the intercooler and its pipes. Any holes drilled in inner panels for intercooler pipes must be no larger than needed for the pipe and fitted with a rubber or similar sleeve.
- Water or alcohol injection is prohibited.
- Water cooling of intercoolers is prohibited.
Justification and Rationale
Similar to the current Group 2B regulations. This is a more sensible approach as repairs to, or replacement of, ND era turbo’s is near impossible.
Most ND era cars that are turbo charged have an inducer diameter much larger than the old MSA restrictor system.
