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 graph showing the 20HP engine power increase from a long duration valve lift.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 117 | |
| Date | 23th May 1927 guessed | |
| 20HP POWER INCREASE DUE TO LONG DURATION OF VALVE LIFT. ENGINE N° 11-GII COMPRESSION RATIO = 5.45 to 1 LARGER VALVES (1.400 DIA.) TWO ZENITH TRIPLE DIFFUSER TYPE CARBURETTORS. SPECIAL LONG DURATION CAMSHAFT. THE HEAVY DOTTED CURVES SHOW RESULTS WITH STANDARD CAMSHAFT, (OTHER CONDITIONS SIMILAR). THE LIGHT DOTTED CURVES ARE A CORRECTION OF THE FORMER, OWING TO A SLIGHTLY GREATER INDUCTION PIPE DEPRESSION. DURING THE STD. CAMSHAFT TEST. BRAKE HORSE POWER B.H.P. B.M.E.P. BRAKE MEAN EFFECTIVE PRESSURE (LBS/□") R.P.M. OF ENGINE. | ||