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).
Comparison of petrol consumption for different axle configurations and compression ratios under various test conditions.
| Identifier | WestWitteringFiles\I\September1922\ Scan75 | |
| Date | 16th September 1922 guessed | |
| COPY COMPARATIVE TESTS OF PETROL CONSUMPTIONS TAKEN ON BROOKLANDS Condition of test. | 15 tooth axle. high comp. | 15 tooth axle. low comp. | 14 tooth axle. high comp. | 14 tooth axle. low comp. --- Car run at 30 m.p.h. on Track. | 16 m.p.g. | 15¼ m.p.g. | 14¼ m.p.g. | 14¼ mpg --- Car run at 50 m.p.h. on Track. | 14¼ " | 14¼ " | 13½ " | 13½ " --- Car run 1 lap 20 " " " 1 " 30 " " " 1 " 40 " " " 1 " 50 " finish at 60 " | 15¼ | 14¼ " | 14¼ " | 14 " --- Run from Brooklands to Derby (140 miles) average speed 31 MPH. | 14 " | --- | 13.75 " | -- --- Run from Derby to Brooklands -140 miles. | -- | 13.5 " | --- | 14 " | ||