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).
Petrol consumption tests comparing different carburettor setups and needles on a 25 HP engine.
| Identifier | ExFiles\Box 102\1\ scan0250 | |
| Date | 1st February 1935 | |
| 45080 To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Hs{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation} Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe}13/KW.1.2.35. Petrol Consumptions - GMD-20. 25 HP. Original old type R.R. carburetter refitted. This carburetter was the identical one removed for modification. On road test the original setting was very weak at low speeds and remained weak up to 40 MPH. on accelerations to such an extent as to rob the car of its performance. Both jets were marked and the consumption checked as follows :- 30 MPH. Constant / 1/4 gallons/ 11.0 miles/ 22 MPG. Fast run not exceeding 60 MPH/ 1/4 gallon/ 9.3 miles/ 18.6 MPG. New type carburetter fitted with XB8 needle; setting O.K., very slight hesitation 35 MPH. onwards. 30 MPH. constant/ 1/4 gallon/ 9.5 miles/ 19 MPG. Fast run not exceeding 60 MPH/ 1/4 gallon/ 7.7 miles/ 15.4 MPG. Same carburetter fitted with XB9 needle; slightly weak at low speeds and slight hesitations from 30 MPH. onwards. 30 MPH constant/ 1/4 gallon/ 10.3 miles/ 20.6 MPG. Fast run not exceeding 60 MPH./ 1/4 gallon/ 7.4 miles/ 14.8 MPG. Summary of tests :- XB8 needle 3 M.P.G. less both tests. XB9 needle 1.4 M.P.G. less at 30 MPH. constant. " " 3.8 M.P.G. less on fast run. HS{Lord Ernest Hives - Chair}/G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Ratcliffe. | ||