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).
Bentley's high-speed performance, future racing plans, and the feasibility of increasing the compression ratio on a 20/25 model.
| Identifier | ExFiles\Box 27a\1\ Scan157 | |
| Date | 22th November 1934 | |
| W/P - Sr. X40/3 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}15/KW.22.11.34. Many thanks for Sr.21/Dn.19.11.34. An average of 112 kms. per hour is somewhat formidable. if you do things like this the justification for giving you a higher compression ratio than standard on the Bentley seems rather obscure! With regard to Hall, we cannot say what he will do next year as yet, but in any case there will be no official entry in racing events, anything that may be done will be on the same lines as the Ulster Show. As soon as any definite move is made we will let you know. With regard to 20/25 performance, we have unofficially talked over with Sg.{Arthur F. Sidgreaves - MD} the possibility of giving you a slightly higher compression ratio for a Continental 20/25. I do not know whether he will agree to this, in the meantime I should like to have your reactions to the suggestion. We cannot raise the compression ratio very much because the tendency of the 20/25 to detonate is rather marked. However, we say that the French petrol is rather better than the English petrol. Do you consider, from your experience of 20/25's on the Continent, that after 10,000 miles a 20/25 would "pink" intolerably if we raise the ratio from 5.7 to 6.25 ? We await with interest your report on the bumper bar. Please do what you can to get this through expeditiously. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||