Wolseley Nomenclature

Most Wolseley model designations consist of two sets of numbers (such as 15/60), a system that appears somewhat cryptic to anyone unfamiliar with it.

Up to 1948 the first number indicated the nominal RAC hp rating, with the second number giving the actual power as measured in brake horsepower. Some models, such as the Wolseley 8, had a designation based on the nominal RAC hp rating only.

RAC hp ratings were used to determine the taxation class of a car. There was an annual fee of £1 per hp payable. These figures did not reflect true power output as the calculation was supposedly based on the engine's cylinder capacity but did not take into account the measurement of the stroke (a situation which led to British manufacturers building long-stroke engines in order that their cars did not attract extra taxation).

The RAC hp ratings were replaced by a flat-rate tax in 1948. The first Wolseleys produced after the change to the road tax legislation were the 4/50 and 6/80. The number of cylinders now replaced the RAC hp figure as the first part of the model designation, with the second figure being the bhp output, as before. Some later models used a figure indicative of the engine capacity as the first part of the number, the first to do so being the 1 ½ litre 15/50 of 1956, followed by the 1½ litre 15/60, the 1.6 litre 16/60 and the 1800cc 18/85. Four cars that did not conform to this system were the 1500, the Hornet, the 1100/1300 and the Six. The bhp figure used in the model designation was however, usually rounded up (or, somewhat surprisingly, even down), presumably for marketing reasons, as shown in the table below. It is therefore only an approximate guide to the engine’s power output.