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).
Track testing, detailing oil temperature issues, petrol supply problems, and recorded lap speeds for various cars.
| Identifier | ExFiles\Box 14\7\ Scan013 | |
| Date | 25th June 1930 | |
| -4- reaches is rather excessive (Graph (4). We have recorded temperatures as high as 110°C. after a prolonged burst of speed on the track with atmospheric temperatures of only 20°C. As the ignition advance of the car is dependent on the relay which in turn is likely to lose efficiency if the oil viscosity is very low, these high oil temperatures seem dangerous from the point of view of causing retarded ignition and hence overheating. It will be observed that the figures in Graph (4) were taken with a ventilated undershield. Lap speed of Cars. We had difficulty with the petrol supply of both 18-EX and 19-EX. After one lap full throttle the mixture weakened off, causing pre-ignition. We found that we could overcome this by running on 'reserve' in the autovac. Presumably the pump does not quite keep pace with the engine requirements for sustained maximum speed. We were running at 3250 engine revs. We are confirming this trouble on the test bed. The maximum lap speeds recorded were :- 18-EX C.O. Open. 79.5 M.P.H. 19-EX C.O. Open. 84.5 M.P.H. American P.1. No cut-out 71 M.P.H. We were astonished at the speed of 19-EX, which is a cabriolet weighing 48 cwt. empty. We think its performance | ||