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).
Test report comparing three new exhaust manifolds against the standard for a 20 HP engine.
| Identifier | ExFiles\Box 6\7\ 07-page024 | |
| Date | 17th January 1928 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/ACL. c. to BJ. Wer. c. to K.{Mr Kilner} DA.{Bernard Day - Chassis Design} c. to GY. HY.{Tom Haldenby - Plant Engineer} 45230 Hs{Lord Ernest Hives - Chair}/ACL1/L/17.1.28. 20 HP. R2. EXHAUST MANIFOLDS. X5230 We have carried out tests on the 20 HP. engine with the three new exhaust manifolds - schemes 934/5/6 - in order to determine which offered the least restriction to the power output. The standard manifold was also tested under the same conditions and all four systems compared for power output with that given by open exhaust. The engine upon which the tests were made was standard with the exception of higher compression ratio 5.45/1 - long duration camshaft and one Zenith triple diffuser carburetter. It was understood that the information was required in connection with the proposed re-designed Phantom therefore the above departures from standard, giving greater power output, were permitted. The experimental manifolds had to inverted to avoid the standard induction manifold and were connected with an open exhaust pipe of 1.75" dia. and 5 ft. long to conduct gas from the test house. The results are shewn on the appended curves. It will be see that all three designs are superior with regard to power output to the present standard manifold. The best system is Sch. 935 - shewn in outline here (over) and is similar to the type we have previously tested on the std. 20 HP contd :- | ||