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).
The characteristics of S.U. carburettors, their performance, and a comparison with Bentley induction systems.
| Identifier | ExFiles\Box 181\M9\ img027 | |
| Date | 11th July 1931 | |
| -3- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}6/Wl.11.7.31.Cont'd.{John DeLooze - Company Secretary} S.U.CARBURETTORS. The S.U's. in spite of being a fixed jet carburetter, seem to break up the fuel stream very well. This of course is a feature of the expanding carburetters since the present standard R.A. shews the same characteristic. The high speed depressions of the S.U. carburetters are lower than any other carburetter we have. This probably explains why they have been used so widely on fast cars recently. The S.U. can be made to give quite fair slow running, but when idling is exceedingly sensitive to mixture strength. The usual practice is to close the throttle completely and fit a separate slow running device which obviates this trouble. Upon enquiry we find that the 8 and 6 1/2 litre Bentley do not use an induction pipe feeding two sets of cylinders but have a common 6 cylinder manifold fed by two carburetters. It is difficult to understand why they do this but may partially explain their slow running. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||