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).
Alterations to the induction system and carburetors to improve fuel economy.
| Identifier | ExFiles\Box 147\5\ scan0154 | |
| Date | 29th October 1938 | |
| 1249 also 1036. To By.{R.W. Bailey - Chief Engineer} c. to Hs.{Lord Ernest Hives - Chair} c. to Ds. c. to Mx.{John H Maddocks - Chief Proving Officer} c. to Da{Bernard Day - Chassis Design}/JNR.{Charles L. Jenner} Rm.{William Robotham - Chief Engineer}2/JH.29.10.38. FUEL ECONOMY. B.III. Two major alterations have been made between B.II and (1) Change from six to four port induction system. (2) Change from 1 3/4 to 1 1/2 carbs. The first change was made because it was desired to make the 25/30 and B.III cylinder heads completely interchange-able and the four port system gives much better idling with a single carb. The second change enables us to reduce the price of the carbs. by more than 50% owing to the smaller unit being a standard production assembly. So far B.III carburation has not been entirely satisfactory, particularly on 8.B.V. the 15,000 miles car which had a number of noticeable flat spots. It was found that the reason that 8.B.V. was so much worse than 7.B.V. was that on the former car sparking over in the distributor head occurred under max. M.E.P. conditions. This explained why this car was bad even on rich mixtures. The attached report shows that there was a reason for complaint with the less costly carbs as originally fitted, but that this can easily be rectified. There is no reason why, other things being equal, we should have a worse consumption on B.III than B.II. Rm.{William Robotham - Chief Engineer} | ||