Listed below are some of the main fuel consumption killers

On recent test-drives organised by Bosch, Ford, GM and other several petrol and diesel cars achieved amazing fuel consumption. But 23 kmpl is really not so remarkable in the hands of a very careful driver. Almost any car can give you anything from five kmpl to 25 kmpl depending on how it is driven and the traffic conditions. Listed below are some of the main fuel consumption killers:

Cold engines. If your car does a five-minute trip to the market and then goes on a series of short trips to the bank, school, friends, et cetera, your engine never gets warm enough to achieve thermal efficiency and your fuel consumption may go up to 50 per cent. So if you have to do short trips do not expect good fuel consumption. It needs about 10 to 15 minutes before your engine is really efficient.

Driving at high engine speeds. If you like to rev up your engine and drive at high engine speeds in each gear, you will get the thrill of fast driving but will have to pay a price for it. Conversely, if you drive like a proverbial old woman and keep the engine at minimum speeds your fuel consumption will be very much better but driving in too low speeds will also cause knocking and shorten engine life. So do not overdo it.

To many stops and starts. Driving in traffic with periods of idling at red lights or when stuck at traffic is a fuel consumption killer. If you spend 10 minutes idling on a 30-minute trip, your fuel consumption may double.

Bad Roads. These can combine the impact of too many stops with the need to use high engine speeds in low gears to get moving so it can play havoc with your fuel consumption.

The weight of the car. All modern engines are quite fuel-efficient but the fuel consumption is mainly affected by the weight of the car. A 600 Kg Maruti 800 weighs half as much as a Civic or Corolla that will need more fuel. Most modern cars must meet current crash safety requirements and are heavier than earlier models and so eat more fuel. But this is a small price to pay for safety.

The load that you carry. This weight factor is naturally increased if your car is overloaded with six people and loads of luggage. If you carry baggage on a roof rack than you will also have the impact air resistance.

Engine tuning and timing. Most modern engines with MPFI and other electronic engine management systems need very little tuning unlike the old carburetors but the nozzles and injectors do need to be cleaned especially with dirty or adulterated fuel that are sometimes encountered. So do not neglect your regular servicing.

Air, oil and fuel filtres. Choked filtres can play havoc with fuel consumption so ensure that these are regularly serviced and changed when they are dirty or clogged.

The official Automotive Research Association of India (ARAI) fuel consumption figures under test conditions assume nearly perfect conditions on a flat one km run so do not believe the figures reported. In the real world, the figures may be out by 25 per cent or more on highways and even more in city driving. These factors apply to every car, bike, truck or bus and if you understand the causes of high fuel consumption, you can make your vehicle much more fuel-efficient.

(The author is the region’s most celebrated automobile columnist)