It is amazing that so many motorists who are fussy about the fuel efficiency of their cars can be so careless about the fuel efficiency of their driving. They angrily change their cars or drivers or look for diesels but are often unwilling to change themselves. They do not realise that simple maintenance and proper driving can make all the difference between 6 kms per litre and 12 kmpl... on the very same car. So here are a few tips:

1. Defective tuning, timing and even the spark plug gap can make an enormous difference. While the friendly neighbourhood mechanic can sometimes do a decent job, there is a considerable element of judgement and luck in their work. Most authorised service stations and some private garages have computerised engine analysers which can ensure very precise accuracies.

2. The quality of your lubricants also plays a part. The expensive new lubes not only give a longer life between oil changes but they also have better detergent, cooling and lubricating properties which help your fuel averages. They are thin oils with high surface tension that reduce engine friction better than the conventional lubes. When oil gets old it loses many of it's properties and should be changed at the specified time. One problem with the new oils, which only need changing after 5000 to 10,000 kms, is that you forget when they need changing. Regular checking is necessary because some oil does get burned and the oil level will go down even if the oil alarm does not light up.

3. With lubes you must also change the oil filter which actually catches all the engine's muck. Similarly check and clean the fuel and air filters because choked filters will immediately raise fuel consumption.

4. Tyres can also be a culprit. If your tyre pressures are just 4psi (.3 bar) too low, your fuel consumption will go up by about 3%. Many tyre gauges are defective so find a reliable pump or keep your own gauge. If in doubt, visually check the tyre which looks properly inflated and match the others accordingly. Also note that after some travel, the pressure in hot tyres increases by upto 4 psi. A little over-inflation does not hurt fuel consumption but it does reduce road-holding so try to fill your tyres when they are cold. Worn out tyres reduce traction and also increase fuel consumption.

5. Increased air resistance from roof-racks, unscientific spoilers and jazzy wheel caps also have their effect. Open windows also increase wind resistance and so can rain or strong cross winds.

6. Consumption also increases if there are short journeys because the engine goes not reach it's peak thermal efficiency temperatures. Hill or winding roads also need constant gear changes which naturally reduces the averages. The same goes for the bad roads that one sometimes has to face.

7. An air-conditioner can increase fuel consumption from 10 to 20% depending on the size of the engine. The bigger the engine, the less the effect because the approximately 2 hp of the compressor has little effect on bigger engines. All music systems, lights and electricals draw a little power and can have a marginal effect.

8. The worst culprit is, however a bad driver. Aggressively racing an engine, in higher than the necessary revs, can reduce consumption by as much as 50%. A good driver will not waste fuel warming up but will warm up the engine with slow initial driving. He will change up to a higher gear as soon as the engine speed permits it and will not also stay too long in a high gear. He will change down into the anticipated gear before accelerating or driving uphill so that the car has enough momentum and does not need furious gear changes and acceleration later.

The easiest way to measure your fuel consumption is to fill the fuel tank up to the very top and then drive for a few hundred kms. Then top up again and divide the kms driven by the fuel consumed. New cars need about 5000 kms before the engines bed down to give the best averages. All averages may, incidentally, be a little lower than they should be because many petrol pumps unfortunately over-meter the fuel.

The fuel averages found on test tracks and claimed by some car makers are very theoretical and are based on ideal conditions of a series of flat, uninterrupted 1 km runs, corrected for 15 degrees Celsius at sea level, etc. Under normal conditions, these averages will come down by at least 20% but upto 40% in city driving.

Saving fuel is important and all these tips, especially your driving, can bring you good savings. If you save just 10% on your yearly fuel bill you can treat your self to a Rs. 3000 splurge...maybe more.