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).
Duplicate report detailing a series of comparative tests on exhaust systems for two experimental car models.
| Identifier | ExFiles\Box 14\6\ Scan250 | |
| Date | 8th June 1932 | |
| Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} FILE 87230. 8.6.32. TESTS ON EXHAUST SYSTEMS. (Duplicate Report). Our first tests were carried out with 20-EX and 22-EX cars on 14.10.31, the exhaust system on 20-EX being much noisier than the one on 22-EX. | Valve Timings on 20-EX | Valve Timings on 22-EX | |---------------------------------|---------------------------------| | .020" tappet clearance. | .020" tappet clearance. | | E.O. 44.2º BBDC I.O. 14º PTDC | E.O. 42º BBDC I.O. 16.6º PTDC | | E.C. 4.2º PTDC I.C. 52º PBDC | E.C. 6.8º PTDC I.C. 55º PBDC | Lagging removed from downtake pipes on both cars. Result. - Swishing noise a little more pronounced, but same on both cars. Next test was to remove lagging from front expansion boxes and intermediate pipes. Result. - Exhaust noises generally 100% worse on both cars - 50% from front expansion box and 50% from intermediate pipe. 15.10.31. Our next test was to change over downtake pipes, expansion boxes and intermediate pipes from 20-EX to 22-EX and vice versa. Result. - 20-EX - 5% improvement. 22-EX - 5% worse. 16.10.31. Cylinder heads changed over completely. Result. - 20-EX - 10% improvement. 22-EX - 10% worse. Total result with cylinder heads and front portions of exhaust systems changed over - 20-EX - 15% improvement. 22-EX - 15% worse. | ||