Pump Till The Last Drop

Got this via email. Readers who frequent the JB-Singapore border area should be familiar to sights like these. As fuel is a price controlled item in Malaysia, smuggling (fuel prices are floated on a free market in Singapore), smuggling is rampant and there will always be cheapskates, irrespective of what make of cars they drive who will try all sort of funny means to save a dollar or two.

By jacking up the car on side, more fuel can be "forced" to in to the fuel tank, filling the volume along the fuel filler neck, which would otherwise have spilled out. All fuel pumps at petrol stations have an auto-stop mechanism that will stop the fuel pump once the vehicle's fuel tank is full. Some drivers, like the one pictured above will jack the car up on its side, and proceed to slowly fill up the filler tank to the brim, pausing between each slow fills to allow the air pressure / bubbles inside be released. More extreme efforts will involve rocking the car from side to side (again to release air pressure in the fuel tank). At least 2 vehicle distributors in the country endorse such methods to be used to obtain their unrealistic, ultra-high fuel consumption figures in their brochures. For some unknown reason, the manufacturer might not be able to provide such figures specific to a local / regional model variant.

A certain amount of air space within the fuel tank is necessary as fuel expands and contracts in relation to their surrounding temperature. This is the reason why a warning against overfilling is stated in every car owner's manual. Without having sufficient expansion space, fuel may leak into the evaporative emission control system, whose main component is a charcoal canister to trap fuel vapour from evaporating to the atmosphere. The canister is not designed to deal with unusually large amounts of vapour or even liquid fuel.

If you really want to get more mileage out of every drop of fuel, stick to the more practical (and larger gains) efforts. In their general order of importance / practicality.
1. Check your tire pressure. It is OK to pump it a tad higher than the manufacturer's recommendation.
2. Drive as smooth as possible with minimal braking and hard acceleration. Anticipate slowing traffic and merging traffic.
3. Swith off your engine if you know the car is going to be idle for more than a few minutes. But be careful, repeated start-ups between short distance drives drains the battery.
4. Remove those roof racks if you are not going to use them.
5. Drive without air-conditioner. Aerodynamic drag with the windows down is quite minimal if your doing below 70km/h or 80km/h. Which is the average speed for a rush hour morning / evening traffic anyway.