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).
Graph comparing constant speed petrol consumption for different car chassis and carburettor settings.
| Identifier | ExFiles\Box 147\5\ scan0153 | |
| Date | 24th May 1938 | |
| M.P.G. CONSTANT SPEED PETROL CONSUMPTION. FIGURES OBTAINED WITH ZENITH MILEAGE TESTER. CAR CHASSIS No. CARB. SETTING 24 G VI ① STANDARD WRAITH ∙060 MAIN JET ∙030 BY-PASS. ② 30 H.P. SETTING ∙063 MAIN JET ∙030 BY-PASS. ③ ∙056 MAIN JET ∙038 BY-PASS. 22 G VI ④ STANDARD 30 H.P. ∙063 MAIN JET ∙030 BY-PASS. CURVES OBTAINED USING VACUUM IGNITION CONTROL ARE SHEWN DOTTED. 45 M.P.H. AV SPEED CONSUMPTIONS ∙056 M ∙038 BP VCI ∙060 M ∙030 BP DIFFERENT CARBS M.P.H. TAS{T. Allan Swinden} / 24 5 38 | ||