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 settings.
| Identifier | ExFiles\Box 183\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. Max. speed for one lap. TABLE: First Column Header: TESTS Second Column Header: High compression. 23¾ cu.ins. Exhaust cut-out Sub-headers: Open, closed Third Column Header: Low compression. 26 cu.ins. Exhaust cut-out Sub-headers: Open, closed Row 1: 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 Row 2: Max. speed for ¼ mile. | 67.4 | 63.5 | 65.22 | 62.7 SECTION: Acceleration. Group 1 (to 65 m.p.h.): 10 m.p.h. to 65 m.p.h. | secs. 37¾ | secs. 50 | secs. 47 | impossible to get 20" to 65" | 34 | 46½ | 41 30" to 65" | 29 | 35 | 38 40" to 65" | 26½ | 32 | 32½ Group 2 (to 60 m.p.h.): 10 m.p.h. to 60" | 30 | 37 | 34 | 42½ secs. 20" to 60" | 27 | 31 | 32 | 36 30" to 60" | 21 | 25 | 28 | 32 40" to 60" | 17 | 19 | 20½ | 23 Group 3 (to 50 m.p.h.): 10" to 50" | 21 | 23½ | 23 | 25 20" to 50" | 17 | 19 | 20 | 22½ 30" to 50" | 12 | 14 | 15 | 17 40" to 50" | 7 | 7½ | 8½ | 10½ SECTION: ¼ mile acceleration test. starting at 10 m.p.h. | 40 | 43 | 45 | 47½ starting at 20" | 36 | 37 | 38½ | 40 starting at 30" | 33 | 33 | 36 | 37 | ||