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).
The results of tests on exhaust system losses using a 114° camshaft.
| Identifier | ExFiles\Box 14\6\ Scan233 | |
| Date | 2nd December 1931 | |
| Y7230. To R.{Sir Henry Royce} FROM Hs{Lord Ernest Hives - Chair}/sn.{Mr Sanderson} c. to Sg.{Arthur F. Sidgreaves - MD} Mf. c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to Ey. Hs{Lord Ernest Hives - Chair}/Bn.{W.O. Bentley / Mr Barrington}4/MA.2.12.31. EXHAUST LOSSES 114° CAMSHAFT. X7230. X7090. We have now repeated the tests of the exhaust system losses using the 114° camshaft to R.2448. The results show how the exhaust losses negative our efforts to get power out of the engine by improved induction and camshafts. Curve R.M.P. shows that as low down as 1000 R.M.P. the M.E.P. is reduced by 7 1/2 lbs/sq.ins., by the silencing system, the back press at this speed being 4.1" of Hg. Whilst at 3000 R.P.M. it is 20" of Hg. Tests that we have carried out show:- (1) That the C.O. valve does not obstruct the pipe appreciably. (2) That we do not loose power through having a front expansion box, and are better off than with a straight through pipe for booms. We are, on the existing size of silencer making further tests to try and reduce back press without sacrificing silence. Previous test on the 25HP. have shown the effect of increasing the volume of the expansion chamber. It is unfortunate that the continental short chassis has less silencer capacity than the Standard car. Hs{Lord Ernest Hives - Chair}/sn.{Mr Sanderson} Attached:- Rs.{Sir Henry Royce's Secretary} P.40. Rs.{Sir Henry Royce's Secretary} F.42. | ||