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).
Data sheet detailing mean lap speeds achieved with various carburetor and silencer configurations.
| Identifier | ExFiles\Box 13\4\ 04-page015 | |
| Date | 23th July 1932 guessed | |
| SHEET (1). DUNLOP RACING TYRES. 6.75 x 21" Tyres. Rolling Circumference 107" at 50 lbs/sq.in. 22-EX. 11 x 41 Axle. 114° Camshaft. Car Weight 50.5 Cwt. Mean Lap Speed. Condition of Car. C.O. Open. C.O. Closed. Std. R.R. Carb. & Silencer. 84.84 80.98. Two S.U. Carbs. with Air Silencer. 91 M.P.H. 84.13 R.R. Semi Expanding Carb. with Air Silencer. 88.35 83.7 R.R. Semi-Expanding Carb. Air Valve Removed. 90.72 85.5 | ||