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).
Petrol consumption and carburetter flooding issues for the 20/25 HP model.
| Identifier | ExFiles\Box 102\1\ scan0334 | |
| Date | 28th June 1935 | |
| X508 To C. from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} C. to Sg.{Arthur F. Sidgreaves - MD} C. to Wor.{Arthur Wormald - General Works Manager} C. to R.{Sir Henry Royce} C. to Hy.{Tom Haldenby - Plant Engineer} C. to Ml. C. to Hr. Petrol Consumption & Flooding - 20/25 HP. Carburetter. Attached is a report on the work so far done on carburetter flooding and petrol consumption on the 20/25 HP. carburetter. It remains to be seen whether the flooding trouble will disappear with the fitting of the filter between the flexible pipe and the carburetter. With regard to the consumption, our experience has proved once again that the present 20/25 carburetter has a consumption which is approximately 1 1/2 miles to the gallon worse than the old carburetter, whilst in return for this consumption a very definite increase in performance is obtained from 50 m.p.h. upwards. It is impossible for us to argue whether or no a man gets as low as 9 miles to the gallon. It is conceivable that during the Jubilee Celebrations the traffic conditions were so bad that such a state of affairs might exist. It is quite positive from our results, however, that if an owner got 8 miles to the gallon with a new carburetter, he would not have obtained any better than 9 miles to the gallon with the old carburetter. We believe that distorted ideas of consumption can be obtained unless the conditions under which the car is used are most accurately recorded, and also the mileage and fuel measured precisely. Sir Banister Fletcher has succeeded in averaging 10 m.p.g. over a run of 1,366 miles, and yet the consumption of the car measured in the presence of his chauffeur over an ordinary run is 16 m.p.g. and his carburetter when run on one of our cars in Birmingham mid-day traffic gave over 15 m.p.g. Again, C. believed his consumption to be bad but on measurement we find this is comparable with that on Wor{Arthur Wormald - General Works Manager}'s car, giving 17 m.p.g. at low speeds and 15 m.p.g. at high speeds. If customers will persist in comparing the consumption of the old carburetter under touring conditions with the new carburetter under traffic conditions, the results will always be disappointing. | ||