A reader in Sweden has sent us the table reproduced below, which indicates power loss through car transmission systems. In the first column is the power output claimed by the manufacturers in D.I.N. b.h.p., in the second column is the power obtained at the driving wheels, and the third column shows the percentage efficiency. Presumably these power outputs at the driving wheels were obtained on a roller dynamometer similar to the Crypton Walker Road Load dynamometer which is becoming popular with the larger garages. Crypton do not provide garages with information on power outputs to be expected from the driving wheels so presumably garages have to discover this for themselves. Crypton have apparently asked manufacturers to provide information of this type but so far this has not been forthcoming.
As can be seen from the table, the Porsche is the most efficient with 91%, followed by the Volvo P.1800 with 86%, Mercedes 190C and Citroen Ami 6 83%, Renault R8 and Skoda Octavia Super 82%. The least efficient appear to be the American Rambler automatic at 54% followed by the manual transmission Rambler at 58%, the Austin-Mini at 59%, and the Ford Zephyr Mk. III at 61%. There seems to be little conformity in the results, such as front-wheel-drive or rear-engined cars being superior to front-engined cars, although of the only two automatic transmission cars in the list both are inferior to the manual transmission versions. No doubt many people would be disturbed to discover, in the case of cars like the Rambler automatic, that nearly 50% of the claimed engine power disappeared by the time it reached the rear wheels, which is probably the main reason why manufacturers are loth to commit themselves on this subject.