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 comparing power output with a 5.25 compression ratio using various carburettor and intake setups.
| Identifier | ExFiles\Box 155\1\ scan0036 | |
| Date | 19th July 1932 guessed | |
| COMPARISON OF POWER OUTPUT WITH 5.25 COMP. RATIO RM.{William Robotham - Chief Engineer}P.53 114° CAMSHAFT (E.82448) (LONG TYPE SILENCER - CUT OUT OPEN) (DOUBLE VALVE SPRINGS) (STANDARD ROCKERS) ① STANDARD P.T CARBURETTER AND INTAKE SILENCER ② SEMI - EXPANDING CARBURETTER AND INTAKE ③ 2 - DIA S.U. CARBURETTERS, BALANCED BY 1/4 DIA. HOLE ④ SINGLE 2 1/2 BORE S.U. CARBURETTER B.H.P. R.P.M. B.M.E.P. LBS/SQ IN | ||