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).
Graph of power tests on a PI Unit, comparing performance with an open exhaust against a standard silencer system.
| Identifier | ExFiles\Box 14\6\ Scan199 | |
| Date | 15th June 1931 guessed | |
| POWER TESTS ON PI UNIT. TWIN CARBS RR 1.400 DIA: CHOKES. R.{Sir Henry Royce} TYPE PHANTOM SHAFT 110° TIMING AS ON 4.G.31. 4:9 COMP: RATIO HEAD WITH DOUBLE VALVE SPRINGS. TAPPETS SET { EXHAUST .008 INLET .006 BAR. 755 m/m B.H.P R.P.M. OPEN EXHAUST. WITH STANDARD SILENCER SYSTEM FITTED. | ||