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).
Table comparing power output and loss in B.HP for various exhaust systems at different engine speeds.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan111 | |
| Date | 12th July 1928 guessed | |
| EXHAUST SYSTEM TESTS - (2) POWER OUTPUT OF STD. SYSTEM AND LOSS IN B.H.P. OF THE OTHER SYSTEMS RELATIVE TO STANDARD SYSTEM. | | B.H.P. with std. exh: system. | LOSS IN B.H.P. RELATIVE TO STD. SYSTEM | | Closed and open refer to the cut-out | |---|---|---|---|---| | | | West WitteringHenry Royce's home town 2 1/4" dia. down pipe. | West WitteringHenry Royce's home town 2 1/2" dia. down pipe. | Derby exhaust scheme. | | R.P.M. | closed. | open. | closed. | open. | closed. | open. | closed. | open. | | 1000 | 48.8 | 50.0 | --- | 0.3 | --- | --- | 0.6 | 0.7 | | 1250 | 60.0 | 62.3 | .6 | 1.1 | .6 | .9 | 0.5 | 0.6 | | 1500 | 68.8 | 72.5 | 1.2 | 1.8 | 1.2 | 1.8 | 0.7 | 0.9 | | 1750 | 74.4 | 80.3 | 1.4 | 2.8 | 1.4 | 2.0 | 1.0 | 1.6 | | 2000 | 78.25 | 85.7 | 1.7 | 3.3 | 1.25 | 2.0 | 1.1 | 1.5 | | 2250 | 78.8 | 87.2 | 1.4 | 3.2 | 0.5 | 2.2 | 1.5 | 1.4 | | ||