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 performance gains from fitting six Amal carburetters to 3.5 and 4.25 litre Bentley engines.
| Identifier | ExFiles\Box 85\4\ scan0177 | |
| Date | 6th August 1937 | |
| To Rm{William Robotham - Chief Engineer} South Plat FRH P & Dec 6. 8. 37 Effect of Six Carburetters on Bentley A standard 3½ litre Bentley was run with the standard induction system & six Amal carburetters. Then the tests were repeated on a standard 4¼ litre unit, results being as shown on figs I & II. In the case of the smaller engine, a gain of 16 BHP was experienced, as against 13 BHP for the 4¼ litre unit. Comparative percentage gains at all speeds are as under. R.P.M | 1000 | 1500 | 2000 | 2500 | 3000 | 3500 | 4000 | 4250 | 4500 3½ LITRE | -2.7% | NIL | 3% | 6% | 9% | 13% | 16% | 17% | 15½% 4¼ LITRE | -2.8% | NIL | 5% | 5% | 8½% | 10½% | 13½% | 15% | 10% It will be observed that the second results are lower than those for the small engine which is what might be expected when it is | ||