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 mean lap speeds for different carburettor configurations on a car with standard tyres.
| Identifier | ExFiles\Box 155\1\ scan0033 | |
| Date | 19th July 1932 guessed | |
| STANDARD TYRES. SHEET (2). 7" x 20" ROLLING CIRCUMFERENCE 104.25" at 50 lbs/sq.in. 22-EX. 11 x 41 Axle. 114º Camshaft. Car Weight 50.5 cwt. Condition of Car. Mean Lap Speed. C.O. Open. C.O. Closed. Std. R.R. Carburetter and Air Silencer. 82.31 80.46 Two S.U. Carbs. with Air Silencers. 89.74 81.77 R.R. Semi Expanding Carb. complete with air silencer. 87.53 81.64 72-JS. {Mr Johnson's Secretary} Continental F.11 5/1 C.R. Std. Camshaft & Carb. with air silencer. 78.7 75.8 25-EX. 5/1 C.R. Std. Carb. and Air silencer. Std. camshaft. 82.5 75.05 * Taken on other occasions. Wind can vary the lap speed by up to 2 M.P.H. | ||