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).
Various exhaust system tests conducted on a 25 HP engine.
| Identifier | ExFiles\Box 6\7\ 07-page183 | |
| Date | 6th November 1931 guessed | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X5230. File under exhaust systems Exhaust Systems-25 H.P. Before 18.G.IV. went to France we carried out a number of tests on exhaust systems. Our impression is that the improved power output of the engine due to a new camshaft and higher compression ratio have somewhat altered the characteristic of the silencer we require to obtain Rolls-Royce standard of silence, and we are therefore carrying out tests here whilst the car is running in France to get a satisfactory exhaust system with the minimum loss of power. resume A brief reminiscence of the tests we have so far carried out:- (1) 2" manifolds. XX Silencer P.II. type silencer. 1 3/8" Fishtail. Results are:- Tinny when ticking over and on the pick up. up to 50 miles at the back of the car. Too much exhaust noise about 60 M.P.H. Exhaust boom in picking up at 50 M.P.H. (2) As (1) but with a cast iron end to the Expansion Box with the pipe led in the front as per diagram. Results are:- Little if any for tinniness up to 50 M.P.H. Booms reduced and raised in speed, worst period now about 60 M.P.H. (3) As (2) but Fishtail changed to 1 1/4" diam. pipe. Results are:- Tinniness as before. Booms improved tp to 60 M.P.H. continued. | ||