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).
Exhaust noise, fuel consumption, and testing on a 20/25 HP coupe.
| Identifier | ExFiles\Box 107\1\ scan0027 | |
| Date | 22th July 1930 guessed | |
| gathered from Mx.{John H Maddocks - Chief Proving Officer} last week, when discussing this matter, that he was not finding any more noise of this nature from the new exhaust systems. I found that the consumption of this car when making these tests under fast touring conditions was 15 miles to the gallon. PN.{Mr Northey} Since dictating the above, I have tested GNR-27, the very nice little coupe 20/25 H.P. made for Mr. Fuller, U.S.A., and I do not find that this excessive hiss exists with this car, which is more or less standard in this respect. I am therefore persevering with our own car to-day (Tuesday) in order to find out, if possible, why the exhaust hiss is so excessive by placing the rear number plate in different positions whilst running at speed. I will of course advise Mx.{John H Maddocks - Chief Proving Officer} and Rm.{William Robotham - Chief Engineer} if I have any information arising from this test, which might reasonably affect their movements on Thursday next. | ||