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).
Page 2 of a letter from Maurice Olley discussing vacuum levels, a booster test, and an intake manifold leak.
| Identifier | ExFiles\Box 40\3\ Scan096 | |
| Date | 30th January 1929 guessed | |
| C O P Y - 2 - (3) They increase the vacuum at low speed full throttle about 30-40%. We do not so far find that the drop in vacuum at high speeds with the booster is any disadvantage, perhaps because high speeds are nowhere possible for more than a few miles. We shall soon be testing the type of booster P-60809, and will let you know the results. The leak into the intake manifold above the throttle is not enough to upset the idling of the engine. We have an idea that it may tend to increase the popping in the exhaust, but this is not certain. Yours faithfully, ROLLS ROYCE OF AMERICA, INC. (Signed) Maurice Olley | ||