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).
Consumption and acceleration tests on a semi-expanding carburetter.
| Identifier | ExFiles\Box 13\4\ 04-page047 | |
| Date | 7th November 1932 | |
| 87080. For Files. 7.11.32. X1725 19-EX. CONSUMPTION TESTS WITH SEMI-EXPANDING CARBURETTER. We have been carrying out consumption tests along with acceleration tests to obtain the best compromise with the semi-expanding carburetter. To obtain the best acceleration we found that an 80 needle was needed. This gave us the same acceleration from 10 M.P.H. as obtained with 20-EX. The 85 needle used during the 10,000 miles test is definitely down in performance for acceleration, 20-EX getting three lengths of the Car ahead in a distance of approx. 100 yards. The 80 needle brought the acceleration of the two cars level and at 50 M.P.H. 19-EX. gradually started to leave 20-EX. Consumption tests taken with both needles over a distance of 112 miles at an average speed of 37 M.P.H. gave the following results. 85 needle 10.37 M.P.G. 80 needle 10.25 M.P.G. A further test with the 80 needle with the control set four notches weak gave :- 80 needle 10.91 M.P.G. It was noticed during the latter test that the carburation had the weak spot which causes misfires during acceleration as was experienced with the first carburetter. There was also a series of semi-explosions in the silencer on the over run. This feature could be cured by bringing the control to normal. The jet control of the semi-expanding carburetter is not very effective at medium or high speeds owing to the movement of the main jet being only .050". | ||