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).
Performance test report from Brooklands comparing Stromberg and S.U. carburetors with standard and free exhaust systems.
| Identifier | ExFiles\Box 108\3\ scan0098 | |
| Date | 29th April 1939 | |
| Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}3/MR.29.4.39. 28.G.VI & 29.G.VI. AT BROOKLANDS. Further to our report Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}10/JR.{Mr James Royce}25.4.39 re tests on Brooklands, we again ran 29.G.VI on the Track on Wednesday last. The cast iron high power unit was fitted to 29.G.VI. The standard Wraith unit to 28.G.VI. Tests were carried out with both the Stromberg carb. and Twin S.U. carbs, standard and free exhaust systems, and engine oil temperature tests with Aluminium and Sheet Metal bottom half crankcases. The car otherwise was in the same condition as in the previous test. Weight 2 tons 1 cwt. 3 qrs. 21 lbs. Petrol consumption from Derby to Brooklands with twin S.U. carbs. fitted - 12.52 m.p.g. Performance Figures. Stromberg Carb. S.U.Carb. Std. Exhaust. S.U.carb. Free exhaust. Best Lap Speed 79.05 mph. 80.59 mph. 82.18 mph. Best Half Mile 82.57 " 84.51 " 86.12 " Stromberg Carb. S.U. carbs. 10 - 20 M.P.H. 5.0 secs. 4.0 secs. 20 - 30 " 3.8 " 3.8 " 30 - 40 " 4.2 " 4.0 " 40 - 50 " 4.2 " 4.2 " 50 - 60 " 6.0 " 5.2 " 60 - 70 " 8.2 " 7.2 " 10 - 70 " 31.4 " 28.4 " | ||