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).
General performance report on the Solex double choke carburetter fitted to a 12-EX chassis.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan101 | |
| Date | 7th February 1929 | |
| Hs{Lord Ernest Hives - Chair}/AJL/LG7.2.29. SOLEX CARBURETTER ON 12-EX. General Performance. The Solex double choke carburetter as fitted to 12-EX is the best static carburetter we have tested out on either of our chassis. The increase in power is very pronounced, it is not necessary to use a stop watch to decide whether the power is better than with our own standard system. The throttle can be opened up suddenly from 5 m.p.h. upwards with good results when the carb. is fitted with 32 mm. chokes, below this speed it will not function in this respect. With the original 34 mm. chokes this fault of course was apparent at a higher speed. The car was never tested by us with the 34 mm. chokes but we understand from The Solex Representative that they were changed in order to reduce this fault, we cannot therefore say what power we are losing at high speeds due to the smaller chokes as against the larger. There are no very apparent weak or rich spots throughout its range, one can detect a weak place between 30 and 40 m.p.h., but it is very slight. One has the impression that the mixture strength at the lower speeds is uniformly too rich, and that if this was reduced we should much more easily detect weak spots. The consumption figures shew very little difference between an average run, including accelerations, and coasting at one fixed speed, as compared with our own carburetter contd :- | ||