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 graph comparing a 3 1/2 litre engine against a 4 1/4 litre development engine.
| Identifier | ExFiles\Box 90a\4\ Scan309 | |
| Date | 4th May 1936 | |
| BENTLEY MAY. 4. 1936 ① 3½ LITRE ENGINE 8.35:1 COMP. RATIO (1935 - T.T.) ② 4¼ LITRE ENGINE 9.0:1 COMP. RATIO (1936 DEVELOPMENT) UP TO MAY 4 BOTH CURVES TAKEN WITH RACING EXHAUST SYSTEMS FITTED BUT IN THE CASE OF THE 4¼ LITRE ENGINE A NEW EXPERIMENTAL SYSTEM WAS USED (RM.{William Robotham - Chief Engineer}75 MANIFOLD WITH 3" BORE STRAIGHT THRO' EXHAUST PIPE) R.P.M. B.M.E.P. C.T.S. | ||