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).
Performance of the 'M' Series Bentley, including horsepower, rev limits, and overdrive, with comparisons to other cars.
| Identifier | ExFiles\Box 146\5\ scan0057 | |
| Date | 11th November 1938 | |
| W/P. Sr. from Rm.{William Robotham - Chief Engineer} 1245 Rm{William Robotham - Chief Engineer}3/R.11.11.38. With reference to Mr. Favier's letter, all we claim for the 'M' Series Bentley is that it is not inferior in performance to the pre 'M' Series car if fitted with the same body. As a matter of fact, we do get a little more horse-power, but its affect on performance would not be appreciable. What we have done on 'M' Series is to get our horse-power at slightly lower revs., as it is not now necessary to run up to 4,500 to get maximum road speed, owing to the overdrive. To prevent customers running on direct and so over-revving their engines, we have made the 'M' series power plant reluctant to go above 4,200 revs. We should be interested to have direct comparisons on Montlhéry of your various cars when they are all thoroughly run in, because we say emphatically that the overdrive does enable one to get a lap speed on Brooklands of one to two miles greater than on our previous cars, and, of course, under favourable conditions, this difference is magnified up to 5 m.p.h. We suggest that having made the test yourself, you convince customers accordingly. I am sure with the Hotchkiss the engine does not give any more horse-power than that of the Bentley. The one I tried was rougher which, of course, gave one the impression of power, and, also, the car was very light, but they had obtained their lightness by sacrificing features which a Bentley owner demands, i.e., suspension, steering and brakes. If Mr. Favier really wants to go fast he must have a 'Paulin' car. Incidentally, if you get a chance to put the 'Paulin' on the track again now it is run in, I shall be interested to know the highest performance. Rm.{William Robotham - Chief Engineer} | ||