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 an experimental engine against a standard 20 HP production engine, detailing power, fuel consumption, and compression ratio effects.
| Identifier | ExFiles\Box 5a\5\ 05-page064 | |
| Date | 9th September 1927 guessed | |
| contd :- -2- Appended are curves shewing a comparison between this experimental engine and the std. production 20 HP. It is noticeable that the peak of the power curve has been raised to apxp approx. 3400 r.p.m. from the standard 2750 r.p.m. and the maximum power increased by 48%. This increase in power is also accompanied by an appreciable reduction in the specific petrol consumption over the whole range. We usually expect a long duration camshaft to slightly lower the power at the low speed but in this case the power of each engine is approx. the same at 500 r.p.m. Probably the increased compression ratio restores any slight loss at these speeds due to the cams, and for this reason we should/expect the engine with the slightly increased compression ratio to be more prone to detonations. Further information on the performance of this engine will be supplied when we get the opportunity to carry out tests upon the road. Hs{Lord Ernest Hives - Chair}/A.{Mr Adams} C. Lovesey. | ||