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).
Overheating, petrol consumption, and the effect of 4-wheel brakes on carburetter settings.
| Identifier | ExFiles\Box 24\5\ Scan047 | |
| Date | 25th May 1925 | |
| R.R. 493A (50M) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. X766 REF: Hs{Lord Ernest Hives - Chair}4/LGS. 5. 25. To BJ. from Hs.{Lord Ernest Hives - Chair} c. to BY: c. to Wor.{Arthur Wormald - General Works Manager} c. to H.{Arthur M. Hanbury - Head Complaints} OVERHEATING. Referring to BJ2/14.5.25. It does not necessarily follow that because the carburetter throttle is open a little wider that more petrol is used. The reason the throttle is opened wider is because owing to the exhaust back pressure there is a certain amount of exhaust gas left in the cylinders, this reduces the suction on the carburetter and the throttle is open more to compensate for this. The standard production cars fitted with 4-wheel brakes went through the same schedule of tests as regards petrol consumption as the cars previous to the 4-wheel brakes. We are informed by the Test Dept. that they noticed no difference in the average consumption on the 250 cars approx. which were delivered fitted with 4-wheel brakes. We are continuing our investigations and will let you know the results when completed. We are confident that the modifications to the choke valve on front wheel brake cars will not account for the increase in consumption in the case you quote. If there is any difference at all, it will be less than 5%. Hs.{Lord Ernest Hives - Chair} | ||