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 fuel consumption figures between Stromberg and 3 SU carburettors, including road test data and engine setup details.
| Identifier | ExFiles\Box 170\1\ img080 | |
| Date | 30th May 1940 guessed | |
| The following are the figures:- Stromberg 3 SU's 20 MPH. = 18.24 MPG. ? - 19.44 MPG. 30 " = 19.16 " ? - 16.75. " 40 " = 16.33 " - 16.57. " 50 " = 15.41 " - 15.00. " 60 " = 14.16 " - 14.41. " 70 " = 12.63 " - 13.12. " 80 " = 11.55 " - 11.77. " We also ran the car whilst fitted with 3 SU carbs (Rx3, Rx1, Rx3 needles) over the Ashbourne, Buxton, Glossop, Bakewell, Matlock, Derby route, at an average speed of 47.17 MPH and obtained a consumption of 14.5 MPG, the Lagonda over the same route giving 12.24 MPG. During all these tests the car was fitted with:- ① EB 4098 Increased throat cyl head 6.3:1 comp ratio. ② Pistons .030" below cyl block face. ③ EB 4512 camshaft, short duration inlet 12° negative overlap. ④ Ignition timed at TDC. | ||