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).
Test report on various exhaust system configurations, clutch slip, and engine rattles.
| Identifier | ExFiles\Box 6\7\ 07-page165 | |
| Date | 4th November 1931 | |
| (2) (4) P.II. type of front expansion box fitted with lagged box downtake and intermediate. Sputting not too excessive but Roaring period at 28-35 M.P.H. still definately there and exhaust becomes noisy at 60 M.P.H. & over. Not so good as with the small manifold Critical crankspeed 62 m.p.h. on 3rd. Clutch slips badly. ? type of fabric. Engine gear rattles at 20 m.p.h. 4.11.31 Tests on exhaust systems continued. - (5) 1 3/4" manifold fitted with straight through pipe. This system is perfectly all right except for a marked period which is like a roar at 30 m.p.h. on the pick up and a boom at 60 m.p.h. on top gear. The boom at 60 m.p.h. is not very bad and may be partially due to the engine. There is a slight boom between 40 - 50 m.p.h. but we believe this to be mainly engine. (6) 1 3/4" manifold fitted with small front expansion box and small intermediate pipe. With this expansion box the period at 30 m.p.h. has completely disappeared and with the box lagged there is little or no tinniness. The worst feature of this arrangement is a roar at 60 m.p.h. as in test (5) but slightly less pronounced. On the whole this system is passable for noise but there is a distinct feeling of loss of power. To improve slipper wheel rattles the spring drive damping load is reduced from 19 lbs to 13-14. (six springs removed). | ||