Can someone please tell me why manual gearbox cars are more economical than auto ones?? I can just about understand why they would be in town but extra urban???
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Slush boxes are less efficient as there is no direct drive between the engine and roadwheels, except when the torque convertor is locked, this is like having a manual, but slipping the clutch a lot to improve drivability. However, some higher speed figures for autos can be more efficient due to the different gear rations between manuals and autos.
From the VCA.gov.uk Web site:
Extra-Urban Cycle
This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75mph (120km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3miles (7km).
Urban Cycle
The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).
Combined Fuel Consumption Figure
The combined figure presented is for the urban and extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.
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Sooty Tailpipes,
Many thanks for this. Makes sense.
RAD
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