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).
Comparison of SU and Stromberg carburettors, discussing idling performance and adaptability to automatic chokes.
| Identifier | ExFiles\Box 147\5\ scan0193 | |
| Date | 20th October 1941 guessed | |
| 4. engine it is best to run it on a test bed. To obtain the best possible setting by putting one S.U. carburettor on an undeveloped induction pipe would be pure luck. 4. Against the S.U. carburettor it used to be stated that the idling was erratic since the needle did not always return to the same place. On the high power head we have gone to a large inlet valve which causes a drop in gas velocity and consequent deterioration in idling far greater than the variation between a Stromberg and an S.U. carburettor. This argument may therefore no longer be held against S.U. ~~~~~~~~~~~~~~~~~~~~~ From the above notes it should be clear that there is only one point at present in favour of the Stromberg carburettor – its adaptability to the automatic choke. That nobody has yet devised a progressive automatic choke on practical lines for S.U. should not be glossed over. It is a fundamental weakness and may lead to a downfall as sure as that of the Brontosaurus or the rotary aero engine. It remains quite certain however that with | ||