Formula around which they had been based prevented the Mark II cars from making a greater impact. The cars last raced around the end of 1955. One of the later drivers was Peter Collins, who, Owen thought, was the only driver other than Fangio who showed the BRM Type 15/Type 30 to its best advantage. The potential of the engine was illustrated in 1968 when Graham Hill drove the car in a demonstration in South Africa, the car being fitted with the original, larger, Rolls-Royce supercharger inlet. Hill revved the engine to 13,000rpm, at which point Rudd thought the engine would have been producing around 780 bhp. Fangio's opinion on the BRM Type 15/Type 30 was; "It was the most fantastic car I ever drove – an incredible challenge in every way." Results The engine was powerful and the car was fast. Reliability, at least early on, was not adequate: the engine suffered from water leaks into the cylinders, due to the use of a separate head/block assembly. (Most previous supercharged car engines used a combined unit). The V16 head-block union was unable to survive the high pressures involved, leading to warping and lifting of the head. Number of Grands Prix 4 Number of starts 2 Number of finishes 2 Number of finishes in points 1 After the fiasco of the Ulster Trophy in June 1952, where both BRM V16-powered Type 15's failed to finish, Stirling Moss wrote to Raymond Mays telling him that he did not want to drive the car in the state that it was in, given its lack of reliability. Conclusion Although reliability was a problem during the car's brief Formula One career, the car and engine went on to become quite reliable after the initial problems had been worked out. Unfortunately this did not occur until after the Formula the car had been designed for had been abandoned. The cars themselves contributed to the changing of the Formula due to Mays' withdrawal of the cars at Turin in 1952. By the time the reliability problems had been solved the car had nowhere to race in the Formula it was intended for. A total of four Type 15s were produced, one of which was written off by a collision during the Glover Trophy and salvaged for spares, while another car that crashed at Albi was used as the basis for one of the two P30s produced.