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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).
Comparison of fuel consumption figures between Stromberg and 3 S.U. carburettors, including test specifications.

Identifier  ExFiles\Box 124\2\  scan0229
Date  27th August 1940 guessed
  
-2-

The following are the figures:-

Stromberg. 3 S.U's.

20 M.P.H. ... ... 18.27 M.P.G.? - 19.44 M.P.G.
30 " ... ... 19.16 " ? - 16.75 "
40 " ... ... 16.33 " - 16.27 "
50 " ... ... 15.41 " - 15.00 "
60 " ... ... 14.16 " - 14.41 "
70 " ... ... 12.63 " - 13.12 "
80 " ... ... 11.55 " - 11.77 "

We also ran the car whilst fitted with 3 S.U. carbs.
(Rx3, Rx1, Rx3 needles) over the Ashbourne, Buxton, Glossop, Bakewell, Matlock, Derby route, at an average speed of 47.17 M.P.H. and obtained a consumption of 14.5 M.P.G., the Lagonda over the same route giving 12.24 M.P.G.

During all these tests the car was fitted with

1) E.B.4098 Increased throat cyl. head 6.3:1 comp. ratio.

2) Pistons .030" below cyl. block face.

3) E.B.4512 camshaft, short duration inlet 12 deg. negative overlap.

4) Ignition timed at TDC.

5) Rear axle ratio 3.73:1.

6) Tyres 6.50 x 16.

All tests run on POOL SPIRIT.

Rm{William Robotham - Chief Engineer}/WYM.{G. Harold Whyman - Experimental Manager}
  
  


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