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 comparison chart for an O.H.C. Bentley (B.23) engine with different manifold and silencer configurations.
| Identifier | ExFiles\Box 97\1\ scan0135 | |
| Date | 11th March 1938 | |
| CURVES SHOWING COMPARISON BETWEEN: 4 PORT MANIFOLD & TWO BENTLEY SILENCERS. 3 PORT MANIFOLD & TWO BENTLEY SILENCERS. (D) O.H.C. BENTLEY (B.23) L.B.8 PLUGS ETHYL FUEL NO AIR SILENCER TAPPETS AT .006" VALVE TIMING WITH .020 CL'CE. I.O. 2° B.T. I.C. 38° P.B. E.O. 43° B.B. E.C. 12° P.T. 1 5/8" CARBS: 1 OPEN EXHAUST 2 4 PORT MANIFOLD WITH 2 BENTLEY EXHAUST SILENCERS. 3 3 PORT MANIFOLD WITH 2 BENTLEY EXHAUST SILENCERS. 4 PORT TO BENTLEY SILENCER TO BENTLEY SILENCER 3 PORT TO BENTLEY SILENCER B.H.P. R.P.M. B.M.E.P. LBS/□" 20" BACK PRESSURE INS: MERCURY. 10" BACK PRESS FOR ② & ③ PRACTICALLY THE SAME. DC.R.LEE 11. 3. 38 | ||