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).
Page discussing carburation and its effect on petrol consumption and engine performance, with a corresponding graph.
| Identifier | ExFiles\Box 147\5\ scan0093 | |
| Date | 12th June 1925 | |
| R.R. 493a (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -9- Expl. No. REF. HS{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG21.11.25 when these are fitted, instead of making a gradual stop with the throttle closed. Again, the average speed of the car almost always is increased when driving with front wheel brakes. This in itself gives an adequate reason for increased petrol cons: CARBURATION. It is not generally realised that if a carb. is set for minimum petrol consumption to give max. power, the car will still not be running under its most economical conditions. A small amount of power must be sacrificed if economy is of primary importance. A much more potent factor, however, is that the mixture can be very much over-rich without any falling off in power and performance. This is quite clearly shewn in Graph lV. the GRAPH lV. Graph text: Y-axis: B.H.P. AND PERCENTAGE THERMAL EFFCY AT 1000RPM. X-axis: PETROL PER LB. OF DRY AIR. Graph Title: TYPICAL CURVES FOR AN EFFICIENT 4-STROKE PETROL ENGINE. Graph Labels: EFFICIENCY, B.H.P, Chemically Perfect Mixture, Max. Power contd :- | ||