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 comparison graph of different exhaust systems against engine RPM.
| Identifier | Morton\M9\ img012 | |
| Date | 11th August 1931 | |
| RM.{William Robotham - Chief Engineer}26 COMPARISON OF EXHAUST SYSTEMS. CHINA 112 SHAFT HIGH LIFT ROCKERS 5.65 C/R STD 15% LARGER CARB. ① OPEN EX. ② PII EX. SYSTEM ③ W.W. NSCH3286 PII FISHTAIL ④ W.W. NSCH 3286 25H.P. FISHTAIL ⑤ STD 25 H.P. SYSTEM ARRGT. E.55794 B.H.P. 90 80 70 60 50 40 30 20 10 R.P.M. 500 1000 1500 2000 2500 3000 3500 4000 11-8-31 EXHAUST BACK PRESSURE INS. HG. | ||