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).
Horsepower (HP) comparison tables at various RPMs for two different exhaust configurations.
| Identifier | ExFiles\Box 48\4\ Scan209 | |
| Date | 1st June 1924 guessed | |
| -2- COMPLETE CURVE WITH ALL ON :- R.P.M. | HP. A. {Mr Adams} | B. 500 | 10.8 | 10.8 750 | 16.3 | 17 1000 | 21.9 | 22.7 1250 | 27.8 | 28.2 1500 | 31.8 | 32.6 1750 | 37.3 | 38.2 2000 | 42.4 | 43.4 2250 | 46.5 | 48.3 2500 | 47.3 | 50.5 2750 | 48 | 51.6 3000 | 47.1 | 51.4 Curve shewing difference in HP. having (a) standard exhaust box fitted with hot spot and - (b) standard exhaust box from which the hot spot gas has been removed - showing the actual loss in HP. when applying hot spot :- R.P.M. | HP. A. {Mr Adams} | B. 500 | 11 | ---- 750 | 17.2 | 16.3 1000 | 22.7 | 23.4 1250 | 27.5 | 28.4 1500 | 32.9 | 33.4 1750 | 37.1 | 39.5 2000 | 43.4 | 44.2 2250 | 46.5 | 48.5 2500 | 48.5 | 49.7 2750 | 49 | 50.4 3000 | 47.6 | 50 | ||