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 comparison between the 4¼ Litre Bentley and the Cadillac 8 Cylinder Vee.
| Identifier | ExFiles\Box 125\1\ scan0294 | |
| Date | 10th August 1936 | |
| X 1052 Bly.{B. W. Bleaney - Bentley Sales} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/MJ.10.8.36. 4¼ LITRE BENTLEY v CADILLAC 8 CYL. VEE. With regard to the Cadillac having the performance of the Bentley this is interesting and I hope you will take the opportunity of rubbing into the administration that here is the Premier British Sports Car latest model being trimmed up on performance by an American family saloon car which costs £400 in U.S.A. You can also take it from me that the performance of the 4¼ Litre will get steadily worse owing to the weight going up exactly as it has on the 3½ Litre. You will probably like to know how it is that the Cadillac manages to beat the Bentley and the answer is as follows - the Bentley is geared to a top speed of 96 m.p.h.; you will find that the Cadillac is geared to 90 m.p.h. We use the higher top gear ratio because we want to be economical in petrol consumption etc., and we say that if a man wants performance he can use his gearbox, the result, however, is that the Cadillac gains 5% on its top gear acceleration on its gear ratio. The next point is in the size of the engine. The Cadillac has a 5.8 litre engine in, the Bentley is 4¼ litres, therefore we should expect the Cadillac to have 41% better acceleration due to its larger engine size. Couple the axle ratio and the engine together and for equal engine efficiency the Cadillac should have 50% better efficiency than the Bentley. The Cadillac however is heavier weighing by your figures 35 cwt. against 33 for the Bentley., i.e. 6% greater. This will reduce the advantage of the Cadillac over the Bentley to something over 35% on the overall power weight ratio. Therefore on this figure alone the Cadillac on top gear ought to beat the Bentley on third speed. If it does not manage to do this the reason is that the Bentley engine is more efficient than the Cadillac. Briefly, therefore, the astonishing thing about the Cadillac is not the additional weight which you speak of in your memo. but the fact that they can produce a car having more room in it than the Bentley and a 40% larger engine, and yet all this is provided in a car only 2 cwt. heavier. This is why I am always fighting to keep the Bentley weight down and to avoid hydraulic jacks, 3" more body room, etc., on the existing chassis. You will find a number of up to date U.S.A. cars with performance similar to the Cadillac, as an example the Century model Buick. In two years you will be selling the 4¼ litre Bentley with | ||