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).
Performance and petrol consumption test report comparing Duplex Stromberg and S.U. carburettors on a Bentley Car 11 B.V.
| Identifier | ExFiles\Box 124\2\ scan0228 | |
| Date | 23th August 1940 guessed | |
| Spare Ev.{Ivan Evernden - coachwork} from Rm.{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} c. JNR.{Charles L. Jenner} c. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} Bentley Car 11 B.V. Unit B.80. No.3. We have carried out performance and petrol consumption tests on 11.B.V. car with a Duplex Stromberg carb. fitted, and alternatively 3 S.U. carbs. With regard to performances, we could not clock any difference in acceleration times from 10 - 80 M.P.H. with either system of carburetters, but using 4.B.50 as a datum car, we were able to establish that the performances of the Stromberg and the 3 S.U's were identical from 10 - 60 M.P.H. but from 60 - 85 M.P.H. the 3 S.U's were better by 2 to 3 car lengths, and as far as we could judge on the road progressively so up to 100 M.P.H. The actual timed figures obtained were:- 10 - 20 M.P.H. ... ... 3.1 secs. 10 - 30 " ... ... 6.1 " 10 - 40 " ... ... 9.1 " 10 - 50 " ... ...12.7 " 10 - 60 " ... ...16.27 " 10 - 70 " ... ...20.2 " 10 - 80 " ... ...25.4 " During our constant speed petrol consumption tests with the Stromberg carb. we were considerably handicapped on our Six Hills test road by the number of Army Lorry Convoys travelling southwards, thus limiting our use of the south directional road to tests at 40 M.P.H. and over, because of the longer distances covered at the lower speeds. Consequently the 20 and 30 M.P.H. tests were done on the north directional road only, and we very much doubt their accuracy, but the results obtained at 40 M.P.H. and over were the averages of runs in both directions, and can be taken as accurate. We had not time to spend another day on these tests because we had to change over to S.U. carbs. in time to run comparative tests with a Lagonda 12 cyl. car, which had been loaned to us for a short time. The figures obtained on the 3 S.U. carbs. are accurate. Continued. | ||