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).
Road test report comparing the performance of Discol and Ethyl petrols in a Bentley car.
| Identifier | ExFiles\Box 150\1\ scan0319 | |
| Date | 1st April 1938 | |
| To Rm. {William Robotham - Chief Engineer} from Rm {William Robotham - Chief Engineer} /FD. {Frank Dodd - Bodies} Rm {William Robotham - Chief Engineer} /FD. {Frank Dodd - Bodies} 3/WH.1.4.38. ROAD TEST ON DISCOL PETROL. Performance tests have been carried out on Discol and Ethyl petrols with the object of checking any difference in detonations, acceleration, weakness etc. Tests were carried out on B.56.BN {W.O. Bentley / Mr Barrington} , a standard Bentley 4¼ litre with deturbulated cyl. head, car weight 34 cwts. 0 qrs. 14 lbs. We found from the acceleration figures that there is a very slight advantage when using Discol, but this is so slight that it would not be noticed under normal driving conditions. The ignition advance was checked with a fixed governor to determine the maximum advance possible just avoiding detonations, figures are shown. It will be observed that we were able to advance 2° earlier on Discol as against Ethyl, at 10 m.p.h. full throttle. At 20 m.p.h. the amount of advance was the same. The car was left running on Discol and covered approx. 700 miles without any comment being made by drivers regarding the running conditions of the engine, adversely or otherwise. It was not found necessary to alter the jet settings at all when the change of fuel was made, slow running was not affected. Acceleration figures Ethyl. Discol. 10 - 20 4.2 4.1 10 - 30 7.75 7.65 10 - 40 11.9 11.45 10 - 50 16.4 16.0 10 - 60 21.4 21.0 10 - 70 28.4 28.1 10 - 80 38.0 37.7 Cont'd. {John DeLooze - Company Secretary} | ||