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).
The specifications and performance of the 27-EX experimental car, sent for evaluation.
| Identifier | ExFiles\Box 65a\3\ scan0308 | |
| Date | 27th October 1931 | |
| To Sg.{Arthur F. Sidgreaves - MD} From Hs.{Lord Ernest Hives - Chair} c. to Wor.{Arthur Wormald - General Works Manager} c. to PN.{Mr Northey} Y770. Hs.{Lord Ernest Hives - Chair}4/MJ.27.10.31. v+663 27-EX. CAR. We are sending this car to London tomorrow with driver and have instructed him to call at Conduit Street and ask for instructions as regards what he should do with the car. As the car has one or two novel features it may be worth while keeping our man, or he could instruct some-one else how to operate it. 27-EX. car represents the best we can offer for Continental P.2 as regards performance. This car is fitted with :- (1) Diamond engine mounting. (2) High Compression Pistons. (3) Modified camshafts. (4) Twin carburetters. The carburetters we consider represent the best we can give as regards silence but there are alterations going through which we know will improve the slow running and metering. We specially want to get your opinion on the amount of carburetter noise and roar. You will observe that the induction noise is bad at full throttle but becomes much less if the throttle is partly closed. At the present time the car is working with an autovac and also an autopulse petrol pump. The intention is to use the R.R. petrol pump, at the moment however, this is not sufficiently reliable to go on a car. The tests on Brooklands show that 27-EX. car is about 7 or 8 M.P.H. faster than the standard car. The view we hold is that we think it is very doubtful that we shall ever adopt twin carburetters for our cars. For the average owner the increase in noise does not justify it. Also our tests on the bench on the 25 HP. show that we can get equal top speed with the single carburetter, and when we have synchro mesh box this will look after the acceleration. The new gearbox however, and a new single carburetter, is still some way off so that the sales position may justify producing a certain number of cars with the twin carburetters. | ||