here is the rule
Turbocharger: The vehicle is limited to a single 2.6 inlet turbocharger. The compressor wheel must protrude into the compressor inlet bore 1/8 inch. The 1/8 inch wheel protrusion must be cut flat and square. NO TAPERED CUTS. The inducer bore on the compressor housing is limited to 2.6 inches and the bore must be uniform in size throughout the diameter. No oval or egg shaped bores will be allowed. The inducer bore is non removable and must be maintained for ¾ of an inch from the front face of the compressor wheel. The inlet will be measured with a 2.65 plug, or internal calipers. The plug must not be able to enter the inducer bore. A map width enhancement (MWE) groove is allowed. No MWE groove width greater than (.200) of an inch will be allowed. The entire MWE groove must be placed behind the cut or step on the wheel for the protrusion into the inducer bore. Turbos with non stepped wheels, true 2.6 or smaller must still have the 1/8 protrusion into the inducer bore, and the 2.6 bore must be maintained for ¾ inch in front of wheel and may have a MWE groove no larger than (.200) of an inch wide behind the face of the wheel. All provision allowing air to the wheel other than via the bore inlet and the MWE groove are prohibited. The 6.4 power stroke engine may utilize the factory twin tu rbo configuration. The driver will be responsible for making compressor wheel and bore accessible for tech personnel to measure bore and inspect compressor wheel.
It will be interesting to see them tech it IMO, can anyone round here pull this class?