From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Performance test results for car 1.EX, a 4-seater open touring body, comparing high and low compression engine configurations.
| Identifier | Morton\M22\ img084 | |
| Date | 13th February 1920 guessed | |
| Particulars of car 1.EX - 4-seater open touring body - windscreen and hood - all accessories - weight complete 46¾ cwts. during tests. 14 X 52 axle ratio. Tests were taken to prove that ignition and mixture were set to give the best results. TESTS. High compression. 23¾ cu.ins. Exhaust cut-out Open | closed Low compression. 26 cu.ins. Exhaust cut-out Open | closed Max. speed for one lap. m.p.h. 71.4 | m.p.h. 65.5 | m.p.h. 69.4 | m.p.h. 65.74 Max. speed for ¼ mile. 67.4 | 63.5 | 65.22 | 62.7 Acceleration. 10 m.p.h. to 65 m.p.h. secs. 37¾ | secs. 50 | secs. 47 | impossible to get 20 " " 65 " 34 | 46¼ | 41 30 " " 65 " 29 | 35 | 38 40 " " 65 " 26¼ | 32 | 32¼ 10 m.p.h. to 60 " 30 | 37 | 34 | 42½ secs. 20 " " 60 " 27 | 31 | 32 | 36 30 " " 60 " 21 | 25 | 28 | 32 40 " " 60 " 17 | 19 | 20½ | 23 10 " " 50 " 21 | 23¼ | 23 | 25 20 " " 50 " 17 | 19 | 20 | 22½ 30 " " 50 " 12 | 14 | 15 | 17 40 " " 50 " 7 | 7½ | 8½ | 10½ ¼ mile acceleration test. starting at 10 m.p.h. 40 | 43 | 45 | 47½ 20 " 36 | 37 | 38½ | 40 30 " 33 | 33 | 36 | 37 | ||