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 development and testing of various induction systems and carburetters.
| Identifier | ExFiles\Box 159\5\ scan0145 | |
| Date | 3rd February 1941 | |
| Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}3/ET.3.2.41. - 3 - GENERAL DEVELOPMENT. Induction Systems 1. With 2 S.U. carburetters. It has been alleged that the B.V. is not as good as the last production series Bentley (B.II, "M" series). This was based on a test on 8-B-V.{VIENNA} It was found later that this had not been a representative test. The necessary modifications have now been made and the weather is preventing the test being repeated. 2. S.U.s on a dual pipe. Tests are in hand on this system. It has to be assumed that there are two justifications for carrying development work beyond the present stage. These are:- a.{Mr Adams} A reasonable power gain at higher speeds. b. Improved economy by virtue of the small pipe. We shall supply the answer to a.{Mr Adams} as soon as the test bed is runnable. The answer to b. can best be done on the road, not on the dual system, but on a 1.250" bore induction pipe. This will provide a more reliable test, and it can safely be said that, if improved economy cannot be produced from a 1.250" pipe over and above that already obtained on the 1.500" pipe of a standard B.V, then it cannot be obtained on a dual pipe. The bore of the small section of the latter is square, equivalent in area to 1.250" dia. 3. The Dual Stromberg. The systems fitted to cars on the road are out of date, both in pipe design and carburetter setting. It has not been thought worth while to have the new 8-cylinder pipes produced, unless the latest carburetters were available from Zeniths. A specification was supplied to them over a year ago, and they obtained six instruments from America. These were not what we had asked for, however, and Zeniths are now trying to modify them to our requirements. | ||