Rover P4 - P4 105R/105S

P4 105R/105S

The P4 90 was not to be the top of the P4 line. Introduced in 1956, the P4 105R and P4 105S used a high-output, 8.5:1 compression (to take advantage of the higher octane fuel that was by then available), version of the 2.6 litres (160 cu in) engine also used in the 90. This twin-SU carburettor engine produced 108 hp (80 kW). Both 105 models also featured an updated exterior, the 105S featured separate front seats, a cigar lighter, chromed wheel trim rings and twin Lucas SFT 576 spotlamps. To minimise the cost of the 105R, these additional items were not standard, however they were available on the (higher priced) 105R De Luxe.

The 105R featured a "Roverdrive" automatic transmission. This unit was designed and built by Rover and at the time was the only British-built automatic transmission (others had bought in units from American manufacturers such as GM). This unit was actually a two-speed automatic (Emergency Low which can be selected manually and Drive) with an overdrive unit for a total of three forward gears. The 105S made do with a manual transmission with overdrive, but could hit 101 mph (163 km).

The Motor magazine tested a 105R de luxe in 1957 and found it to have a top speed of 93.9 miles per hour (151.1 km/h) and acceleration from 0–60 miles per hour (97 km/h) of 23.1 seconds. A fuel consumption of 23.6 miles per imperial gallon (12.0 L/100 km; 19.7 mpg) was recorded. The test car cost £1696 including taxes of £566.

When production of the 105 line ended (in 1958 for the 105R and 1959 for the 105S), 10,781 had been produced, two-thirds with the manual transmission option. For 1959 the manual model was described simply as a 105 and the trim and accessory level was reduced to match the other models.