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 results of fitting a Solex Duplex carburettor to a Phantom II engine.
| Identifier | ExFiles\Box 13\3\ 03-page179 | |
| Date | 7th January 1930 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/ACL. c. to Sk. Nor. c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to Ey. 87080. Hs{Lord Ernest Hives - Chair}/ACL.1/MJ.7.1.30. X3603. X7080 SOLEX DUPLEX CARBURETTER. TESTS ON PHANTOM II ENGINE. Sometime ago we carried out tests on Phantom I with a twin Solex carburetter and from both test bed and road performance found a considerable improvement over the Std. chassis carburetter. The results of these tests were given in our reports Hs{Lord Ernest Hives - Chair}/ACLL/LG7.2.29., and Hs{Lord Ernest Hives - Chair}/AJL/LG7.2.29. We have since repeated the test on a Phantom II engine on the tests bench and obtained excellent results. A similar induction system was employed as on Phantom I except of course six ports. An exhaust heated patch was used round the bend from the risers and the carburetter was fitted close to the manifold. A sketch of the induction arrangement is appended. The carburetters were fitted with 32 m.m. dia. chokes which, with the diffusers, gave a free choke area of .693" sq. ins. The induction manifold was kept quite small- only 1.575" dia. The distance from the centre line of the manifold to the tops of the diffusers was 5.5". It appears important to keep the carburetter as close to the manifold as possible as it improves the engine response to throttle opening and improves 'snap' acceleration. Also we found there was an improvement in power by keeping the carburetter close because when extension pipes were employed, which lowered the carb. | ||