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).
Comparative test results for a standard Bentley at Montlhery Track comparing high compression and standard cylinder heads.
| Identifier | ExFiles\Box 82\3\ scan0235 | |
| Date | 2nd May 1935 | |
| .Knoo a 25 RUE GIDE LEVALLOIS-PERRET. Seine, France. 2nd May 1935. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From G.W.H. 5 B IV. We have carried out comparative tests on the Montlhery Track with a standard head obtained from a standard Bentley. The following are the results, 19" road wheels used in each case :- HIGH COMPRESSION HEAD. Cut-out closed. Max. Engine Revs...........4.350 Oil Temperature ........ 102° Water " ........ 78° Average Lap Speed ...... 88.5 MPH. HIGH COMPRESSION HEAD. Cut-out Open. Max. Engine Revs...........4.450 Oil Temperature.........120°c Water ".........78°c Average Lap Speed......89.9 MPH. STANDARD HEAD. Cut-out Closed Max. Engine Revs.......4.250 Oil Temperature......110°c Water "......82°c Air "......18°c Average Lap Speed......85.59 MPH. Standard Induction Pipe. STANDARD HEAD Cut-out OPEN Max. Engine Revs.......4.450 Oil Temperature......115°c Water "......82°c Average Lap Speed......87.4 MPH. Standard Induction Pipe. STANDARD HEAD Cut-out Open [text is struck through] | ||