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).
Comparing the performance and specifications of various cars, including the Phantom and Bentley.
| Identifier | ExFiles\Box 69\4\ scan0292 | |
| Date | 23th October 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}4/LG231025 140 clutch B.HP. available while the Phantom has only 109 B.HP. The increased efficiency at high speeds on the Bentley may be accounted for by four overhead valves per cylinder and higher compression ratio. It is, however, a remarkable power output being 20% better than the Hispano, an engine of the same size. | CAR. | Wt. of car. No passengers. Tons. | Displacement. | Direct Drive ratio. | Displ: per ton per wheel rev. of 104" | | :--- | :--- | :--- | :--- | :--- | | 40 HP. Fiat. | 2.15 | 4,766 | 4.08 - 1 | 9044 | | ++ Austro-Daimler. | 1.25 | 2,650 | 4.9 - 1 | 11,200 | | 20 HP. R-R.{Sir Henry Royce} (pre. F.W.B.) | 1.50 | 3,130 | 4.6 - 1 | 10,050 | | Hispano-Suiza. | 2.25 | 6,600 | 3.365 - 1 | 9,900 | | Phantom. | 2.568 | 7,660 | 3.467 - 1 | 10,400 | | Bentley. | 2.00 | 6,600 | 4.16 - 1 | 13,500 | ++ Open car. All others are closed cars. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||