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).
Inferiority of the standard Bentley exhaust system compared to a dual system fitted to the Jaguar.
| Identifier | ExFiles\Box 86\3\ scan0222 | |
| Date | 22th April 1938 | |
| 623? To Rm.{William Robotham - Chief Engineer} from Sg.{Arthur F. Sidgreaves - MD} re Exhaust System. Copy to Hs.{Lord Ernest Hives - Chair} BV [Text struck through] Referring to Rm{William Robotham - Chief Engineer}5/R9.4.38 I have referred back to the report Rm{William Robotham - Chief Engineer}/Ed{J. L. Edwards}6/JD.{J. Draper - Frames}5.11.37 and a study of this seems to indicate that the standard Bentley exhaust system is inferior in all respects to the other systems tried, notably inferior to the dual system such as is fitted to the Jaguar. In fact there seems to be a difference of about 20% in the loss of power between the Bentley single pipe system and the system with twin downtake pipes to two silencers on the rear. I cannot imagine that those responsible at Derby feel very pleased that this inexpensive Jaguar has developed a system which for a sports car appears to be infinitely superior to ours. The particular point, however, that interests me is in regard to B.III. You will remember we were very much concerned months ago when it was indicated that the B.III by reason of increase of weight might be worse for performance than the Bentley of to-day. We said such would be lamentable. As it was known at Derby over 5 months ago that very considerable improvement could be effected by this separation of the exhaust, I assume every advantage of it has been developed for B.III and I should like to have full particulars of the test results obtained. I see your latest note makes it clear that two separate exhaust systems can be made more simply than a single system and that, therefore, cost and weight would not be excessive. Sg.{Arthur F. Sidgreaves - MD} | ||