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 development and benefits of duplex exhaust systems for various engines.
| Identifier | ExFiles\Box 99\1\ scan0159 | |
| Date | 9th May 1938 | |
| H23? γ By.{R.W. Bailey - Chief Engineer} from Rm.{William Robotham - Chief Engineer} c. SG.{Arthur F. Sidgreaves - MD} c. Hs.{Lord Ernest Hives - Chair} c. RHC.{R. H. Coverley - Production Engineer} c. Da.{Bernard Day - Chassis Design} c. Mx.{John H Maddocks - Chief Proving Officer} Rml/R.9.5.38. EXHAUST SYSTEMS. The basic facts we seem to have established about exhaust systems recently are:- (1) By using a duplex exhaust system on a common manifold we can silence the car with almost 50% less back pressure than with a single system. This enables us to gain in high speed power. (2) If we want to gain at intermediate speeds, where improved performance is of the greatest value to the customer, we have got to have a duplex manifold as well as duplex silencers. We have arranged for this on the new cast iron B.80 engine, but cannot get it on the present Wraith-B.60 engine without re-designing the cylinder head. It is clearly not worth doing this in view of the new engine, the drawing of which will be completed in about eight weeks. It is satisfactory to note from the curves attached to Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}1/MR.9.5.38. that we have already got a result on B.III engine with exhaust system that provides 8 to 10 more top H.P. than the present M.{Mr Moon / Mr Moore} Series Bentley coupled with better idling, more silent valve gear, and 7% more output at intermediate speeds. Rm.{William Robotham - Chief Engineer} | ||