Abstract
The objective of this study was to ascertain whether the 5 speed gearbox (5SG) used less fuel than the 4 speed gearbox (4SG). The experiment was carried out with 10 non professional drivers, using 6 car models which were available with both 5 and 4 speed transmission, on a route which combined urban, ringroad and motorway sections. Each driver completed the circuit 5 times with each version of the transmission type. Vehicle and engine speeds and fuel consumptions were monitored, and use of the various gears was derived from vehicle and engine speeds. Analyses were performed for each road type and for the whole journey. The results show little difference in fuel economy between the two gearboxes.