2005 Saab 9-3 Owner's Manual - Page 181
2005 Saab 9-3 Manual
Page 181 highlights
Starting and driving 179 Economical driving Factors affecting fuel consumption The fuel consumption of a car is greatly affected by driving conditions, climate, road conditions, speed, driving technique, etc. Breaking-in Fuel consumption may be somewhat higher during the break-in period (the first 3,000-4,000 miles (5,000-7,000 km)). Weather conditions Summer temperatures give better fuel economy than winter ones. The difference can be as much as about 10%. Consumption increases in cold weather because the engine takes longer to reach its normal operating temperature. The transmission and wheel bearings also take longer to warm up. Even distance affects consumption: short journeys of 3-5 miles (5-8 km) do not give the engine enough time to reach its optimum temperature. Wind conditions also have a marked effect on fuel consumption. How to read the diagram: If fuel consumption with the engine at normal temperature is 28 mpg (10 l/ 100 km), the actual fuel consumption 3 miles (5 km) after the engine has started from cold will be: - 23.5 mpg (12 l/100 km) at outside temp. of 68°F (+20°C) (increase of 20%). - 17.7 mpg (16 l/100 km) at outside temp. of 32°F (0°C) (increase of 60%). - 14 mpg (20 l/100 km) at outside temp. of -4°F (-20°C) (increase of 100%). It is clear from the diagram that both distance driven and outside temperature have a significant impact on fuel consumption, after a cold start. If the car is normally driven on short journeys, 3-5 miles (5-8 km), for example to and from work, the average consumption will be 60-80% above the normal level. Percentage increase in fuel consumption of engine starting from cold compared to engine at normal temperature. Driving techniques • To obtain the best running economy, with regard to fuel consumption and general wear, the car must be serviced regularly. • High speed, unnecessary acceleration, frequent braking and much changing down all give higher fuel consumption. • Frequent gear changing in traffic, starting in cold weather, the use of studded tires and roof racks, and towing a camper all increase fuel consumption. • Do not warm up the engine while the car is stationary. If idling, the engine will take much longer to reach its optimum temperature, and