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 between a 2-S.U. system and a dual Stromberg carburettor, focusing on fuel economy and the effects of damping.
| Identifier | ExFiles\Box 159\5\ scan0136 | |
| Date | 3rd February 1941 | |
| Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}3/ET.3.2.41. - 4 - We believe that, if and when this job has been completely thrashed out, there will be nothing to choose between a 2-S.U. system or a dual Stromberg for fuel economy or price. This is based on the fact that B.V. and wraigh are identical in Ton/Miles per gallon (see Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}10/MI.14.3.40). We also believe that B.V and B.II are identical, on the same basis, but with one possible difference, namely the damped air-valve on B.V. It is a fact, however, that the damper does allow a weaker setting to be used, and the "accelerator pump effect" should at least cancel out, but only if the right amount of damping is determined beforehand. This is a road job, and varying degrees of damping are obtained by altering the length of ball travel in the damper piston. It is detrimental, therefore, to have more damping than required, and just as important as using the smallest accelerator pump jet that can be got away with on a Stromberg. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||