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).
Experimental modifications to engine induction and exhaust piping, detailing their effects on performance.
| Identifier | ExFiles\Box 50\3\ Scan026 | |
| Date | 25th February 1921 guessed | |
| -2- This arrangement was very good so we proceeded to get castings along the same lines, with the exception of additions suggested by an experiment with a 1 1/4" induction pipe with little gutters round the ports where they merge into the main pipe. We did this to prevent the petrol falling in a liquid state into the valve ports, and the smaller pipe was to increase the gas speed. This pipe was a success but rather cut down the engines power. We tried out the casting after fitting several modifications such as a nozzle to throw the gas on the hot grid and instead of allowing the exhaust gas to escape we interchanged it between the 2 exhaust boxes. This proved too efficient, and made things so hot that the engine pre-ignited badly on the battery ignition but not on magneto with plugs in central position. | ||