Capacity multipliers for Turbos and Rotaries
If you are unsure of the capacity of your vehicle, look under the bonnet for the compliance plate which lists what type of vehicle etc, including (normally) engine capacity. If your car is a 2WD Turbo (or Supercharged), simply multiply the capacity by 1.7.
eg A Nissan 200SX is a 2000cc (2 litre) engine, multiply by 1.7 = 3400cc ,which places it in D Class.
Rotary engines have their capacity multiplied by 1.8.
10a (R100, RX3) (just under 1000cc [982cc]) x 1.8 = 1767cc, which is in B class,
12a (RX2, early RX7)(1146cc) x 1.8 = 2062cc, and,
13B (RX4, RX5, late RX7)(1308cc) x 1.8 = 2354cc which are both C Class.
A turbo or supercharged rotary has the above CC's multiplied by the 1.7 factor again,
10a x 1.8 = 1767 x 1.7 = 3004cc,
so all blown rotaries are in D Class, regardless of which variety.
The details are here on the Motorsport Australia website