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).
Report comparing different manifold and carburetter designs, including sketches and test results for models EAC.10 and EAC.14.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan182 | |
| Date | 7th February 1928 guessed | |
| contd :- -2- With the built up pipe the connecting passage between carburetter and manifold changes its section much earlier and the change of section from circular to slotted is more gradual. It would appear that the former - i.e. single piece pipe - with its more abrupt change of section, spreads the charge better before it enters the manifold through the slot. Having proved that the better of these two manifolds gave superior results to the standard type used on the EAC.14, we made an experiment in which the carburetter was lowered to its normal position by means of a short vertical pipe, as shewn in sketch. MODEL FOR EAC.10 Short vertical pipe added to bring carb. in normal position for EAC.14 The results, for all practical purposes, were as good as the pipe in its original form although there appeared to exist the slight tendency of the system to loose some of its good distributing qualities with the carburetter lowered. Apart from bench tests we have run this manifold on the road and found the low speed full throttle pulling of the engine better than standard. The difference is all the more evident if the engine is cool; the weir pipe gives steady low speed full throttle operation whereas the standard manifold rapidly 'loads up'. contd:- | ||