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).
Results of exhaust system loss tests conducted using a 114° camshaft.
| Identifier | ExFiles\Box 13\2\ 02-page155 | |
| Date | 2nd December 1931 | |
| X7090 Hs{Lord Ernest Hives - Chair}/Sa.4/A.2.12.31. X7330 X7090 M Hs{Lord Ernest Hives - Chair}/An. c. to Sg.{Arthur F. Sidgreaves - MD} Or. c. to A.{Mr Adams} Da.{Bernard Day - Chassis Design} c. to Sy. EXHAUST LOSSES 114° CAMSHAFT. We have now repeated the tests of the exhaust system losses using the 114° camshaft to No244B. The results shew how the exhaust losses negative our efforts to get power out of the engine by improved induction and camshafts. Curve R.M.P. shews that as low down as 1000 R.P.M. the M.E.P. is reduced by 7# 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 21" of Hg. Tests that we have carried out shew:- (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 shewn 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. IE/Sn.{Mr Sanderson} Attached:- No. P.40. No. P.42. | ||