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 Brake Horse Power vs RPM for different exhaust manifold pipe systems on engine SS-15.
| Identifier | ExFiles\Box 92\2\ scan0064 | |
| Date | 10th January 1930 | |
| 10-1-30 V767. COMPARISON OF MANIFOLD PIPES - EXHAUST SYSTEM TO N.SCH. 2931/2/47 (S.S.) THESE CURVES SHEW THE POWER OBTAINED WITH THE ABOVE EXHAUST SYSTEM, WHEN USING ① A 3.0" MANIFOLD PIPE (REDUCED TO 2.5" AT LOWER END), AND ② A 2.5" MANIFOLD PIPE. ENGINE N° SS{S. Smith}-15 (STANDARD) CURVES CORRECTED TO N.T.P. CUT-OUT OPEN. 3.0" DIA PIPE. 2.5" DIA PIPE. CUT-OUT CLOSED. 3.0 DIA PIPE 2.5" DIA PIPE. BRAKE HORSE POWER. 140 120 100 80 60 40 R.P.M. OF ENGINE. 500 1000 1500 2000 2500 3000 | ||