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).
Testing various induction pipes and balance pieces to reduce noise and improve engine performance.
Identifier | ExFiles\Box 31\5\ Scan030 | |
Date | 17th March 1933 guessed | |
-2- This balance piece reduced the induction roar tremendously and in every other respect was as good as the .500" hole except that the weak spot previously referred to, was slightly worse, but we think that this can be overcome by a little more heat to the hot spots, because when we disconnected the exhaust hot spot pipe from the small silencer, thus giving the exhaust a straight through flow we overcame the weak spot. Hs{Lord Ernest Hives - Chair}, Rm{William Robotham - Chief Engineer}, GWH{George W. Hancock - Head Chateauroux}, and Roberts tried the car with the above balance piece fitted and appeared quite satisfied with the car's general performance. We next tried an induction pipe built up by Mr. Skinner of the S.U. Company, which had the carbs. placed nearer the ends of the pipe, the front one being between Nos. 1 & 2 cylinders, and the rear one between Nos. 5 & 6 cylinders. This pipe had no balance piece in the centre, and was quite good for induction roar, but our slow running was not quite so good and the weak spot was infinitely worse, in fact the engine was generally lacking in snap up to 45 m.p.h. In its present condition, we do not consider this pipe as good as the R.R. one. We should however, like to try a cylinder head on 19-G-IV giving two hot spot feeds to the induction pipe instead of the present single feed. We have also tried an experimental air silencer on this car, but although we attained a decent degree of silence, we found that at 62 m.p.h. on 3rd. gear the engine began to misfire due to the mixture being too strong, which points to the fact that a 2.500" dia. intake pipe is too small and restricts the air flow at high speeds. Before we can carry out any further experiments with an air silencer for Bensports, we require some power loss figures from the test bed to enable us to determine the smallest diameter of intake pipe that we can use. Hs{Lord Ernest Hives - Chair}/G.H. Whyman. | ||