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).
Engine performance, ignition, and a comparison of India vs. Dunlop tyres on an S.S. Mercedes.
| Identifier | ExFiles\Box 3\6\ 06-page084 | |
| Date | 6th November 1935 guessed | |
| -5- The engine was not the least bit oily and never missed a beat, though I thought I noticed once or twice, when running with the cut-out open, that the note of the engine at high revolutions was not quite so crisp. If I was right in this, it was probably merely a matter of carburation, but without carrying out any definite experiments I could not be absolutely certain. With regard to the ignition, I rather wondered whether the ignition was as well advanced as it might have been. Here again only experiment could have shown. The car was fitted with India tyres throughout. At the request of the India Tyre Company I once consented to run a set of India tyres on my S.S. Mercedes, following very carefully the instructions given me by the India Tyre Company, for the purpose. The result of fitting the India tyres to the Mercedes was that the car got practically out of control altogether; every sort of experiment in tyre pressure and shock absorber adjustment was tried, and not until Dunlop tyres were refitted did the car become normal. I only mention this point because I regard any car fitted with India tyres with grave suspicion, that is to say, if I did notice anything about the car that I did not like I should have been quite ready to put it down to the tyres. This opinion is, of course, given in strict confidence. With regard to the running of the car generally, I can only describe it as being really perfectly wonderful. It is a beautiful car and I do not think I have ever driven a super-charged car with an equal performance, except perhaps the S.S. Mercedes when not using the blower. The acceleration of the Bentley is fully equal to the acceleration of the S.S. Mercedes when not using the blower. The car felt heavy and I should very much like to know the weight; I imagine that it was about 2 tons, or perhaps a little over. It would also be interesting to know the compression ratio of the engine. P.T.O. | ||