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).
Comparison of two exhaust silencer systems for a Bentley V, focusing on power loss.
| Identifier | ExFiles\Box 97\3\ scan0047 | |
| Date | 9th February 1939 | |
| By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} c. By/McStay. Rm{William Robotham - Chief Engineer}/CTS{C. Trot Salt - Carburation}3/R.9.2.39. BENTLEY V.{VIENNA} Exhaust silencer (Power Loss). Purpose of Test. To compare two types of exhaust system for power loss:- (1) The standard B.II system having a cut-out fitted immediately after the intermediate silencer. (2) An experimental system, comprising the double outlet manifold EB.4092. Two downtakes to the intermediate silencer (deleting the first expansion box). This intermediate silencer has an expansion chamber in its rear portion, making the cut-out effective for both downtakes. A second connection is taken from this expansion chamber, which goes to the normal rear B.II silencer and tail pipe. Method of Test. The development unit for the Continental Bentley was used for this comparison. Result. Considering Graph No.S.75, Curve No.(1) shows the open exhaust power of the development unit in its present form. Curve No. (2) shows that by fitting the standard Bentley II exhaust system complete, we lose 18 BHP., and the loss is reduced to 11 B.H.P. by opening the cut-out. Curve No (4) shows that slightly more power is lost to the experimental system complete, but when the cut-out is open, and advantage taken of the separated downtakes, the loss is reduced to 3.B.H.P. If two complete exhaust systems were fitted (Jaguar principle), the total power loss would just about equal the effect of cut-out open on the standard exhaust system. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||