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).
Page detailing fuel octane requirements and the effects of supercharging on engine durability and spark plugs.
| Identifier | ExFiles\Box 140\1\ scan0225 | |
| Date | 28th March 1938 guessed | |
| -21- The fuel octane number requirements for the 4.25 to 1 compression ratio supercharged engine were determined only at a carburettor air temperature of 170 degrees Fahrenheit. These data are presented in Table V.{VIENNA} Blends of C.F.R. Reference Fuels C-9 and A-4 and lead treated Reference Fuel C-9 were used as the fuels. Table V.{VIENNA} Intake Manifold Pressure, C.F.R. Motor Method Octane Inches of Mercury Absolute. Number of Blends of Reference Fuels C-9 and A-4 to Produce Incipient Knock at 1000 r.p.m. with 4.25 to 1 compression ratio. 34.0 66 - 68 36.0 71 - 73 38.0 74 - 75 40.0 78 - 79 42.0 82 - 83 44.0 84 - 85 46.0 85 - 86 48.0 86 - 87. Effect of Supercharging On Durability of Engine Parts. Any designer faced with the problem of converting a standard engine to a supercharged unit is confronted not only with the immediate problem of adopting the supercharger to the engine, but also with the effects of supercharging on the life of engine parts. No intentional endurance tests of the engine used during this program were conducted, consequently any data presented concerning the equipment are the result of secondary observations rather than of a definite test program. The spark plugs were commercial plugs purchased on the open market, and the only requisite was that they should per mit smooth running of the engine at the various conditions of operation. If a particular plug failed from preignition, it was replaced with a colder type, and similarly a hotter type plug was installed if fouling occurred. No commercial automotive plug was found which would operate over the entire speed range at an intake manifold pressure of 10 inches of mercury above atmospheric, but it seems probable that satisfactory plugs could be developed, should the necessity arise. | ||