Have driven some miles with it showing zero on the computer.

 

When it flips from 5 miles down to zero then clearly you have 5 miles in the tank and there is bound to be a margin of course.

 

Do not want to do too many miles on zero as the danger of air going in to the fuel system and causing cavitation damage.

 

Cases of people driving over 40 miles on the zero on some of the VAG and other brand cars.

 

More fuel in the tank means not only worse fuel consumption carrying all that weight but more wheel spin I find!

 

Run until I can get to the nearest Momentum or Nitro garage and then fill with 45 litre, venting if necessary.

When I had the diesel C4 I used to let it run down to the warning light, then some (drove it a few times showing 0 miles range as well when I got caught too far from a petrol station). The reason for doing that was the Eolys supplement that PSA uses on its modern diesel cars, and this refuelling approach ensured that excess amounts of this expensive fluid were not pumped into the fuel tank.

With the Skoda (which is petrol), I usually hit a petrol station as soon as it gets to the red, often a bit earlier. With no Eolys and DPF to worry about, incremental fill-ups are viable for me again.

The fuel gauge means very little, I look for a filling station when the trip meter says 300 miles.  If it's a long trip on fast roads I might let it go to 330 before thinking about filling up. 

The fuel gauge means very little, I look for a filling station when the trip meter says 300 miles. If it's a long trip on fast roads I might let it go to 330 before thinking about filling up.

May i ask why?

Why not use the fuel gauge? (:

1. Fill up your car or truck in the morning when the temperature is still cool. Remember that all service stations have their storage tanks buried below ground; and the colder the ground, the denser the gasoline. When it gets warmer gasoline expands, so if you're filling up in the afternoon or in the evening, what should be a gallon is not exactly a gallon. In the petroleum business, the specific gravity and temperature of the fuel (gasoline, diesel, jet fuel, ethanol and other petroleum products) are significant. Every truckload that we load is temperature-compensated so that the indicated gallonage is actually the amount pumped. A one-degree rise in temperature is a big deal for businesses, but service stations don't have temperature compensation at their pumps.

 

2. If a tanker truck is filling the station's tank at the time you want to buy gas, do not fill up; most likely dirt and sludge in the tank is being stirred up when gas is being delivered, and you might be transferring that dirt from the bottom of their tank into your car's tank.

 

3. Fill up when your gas tank is half-full (or half-empty), because the more gas you have in your tank the less air there is and gasoline evaporates rapidly, especially when it's warm. (Gasoline storage tanks have an internal floating 'roof' membrane to act as a barrier between the gas and the atmosphere, thereby minimizing evaporation.)

 

4. If you look at the trigger you'll see that it has three delivery settings: slow, medium and high. When you're filling up do not squeeze the trigger of the nozzle to the high setting. You should be pumping at the slow setting, thereby minimizing vapors created while you are pumping. Hoses at the pump are corrugated; the corrugations act as a return path for vapor recovery from gas that already has been metered. If you are pumping at the high setting, the agitated gasoline contains more vapor, which is being sucked back into the underground tank so you're getting less gas for your money.

As an example the coefficient of expansion of diesel is 0.00082%  per 1C 

 

So, for an average 50 litre tank full. the difference is 4cc - less than a teaspoonful.

 

Fuel is dispensed at a nominal 15C, so you are only "losing out" when the temperature exceeds this level.  Even in the hottest periods in late summer in the UK when temperatures may occasionally reach around 30C - 35C, on a full tank you would still only be "losing" 60cc - 80cc per tankful.

For the rest of the year you would be "gaining"

 

This may be relevant if you are running a Mack truck, in Arizona, filling up its 1500 litre tank every day, (which is where the article that the above information was copy / pasted from was probably aimed - the words truck, gasoline and gas tank are the give away)

I don't think I'll worry about it personally.

I could more than compensate for the loss of fuel by making sure I increase my MPG  by reducing the GVW of the car by having a good **** before I go out.

May i ask why?

Why not use the fuel gauge? (:

The trip recorder is far more accurate measure than the fuel gauge.  It's a habit I have from previous cars with less than reliable fuel gauges.  If you know approximately what the car will do in terms of MPG and the size of the tank the maths is easy.    Another advantage is the passengers don't panic when they see the yellow light on !

 Hoses at the pump are corrugated; the corrugations act as a return path for vapor recovery from gas that already has been metered. If you are pumping at the high setting, the agitated gasoline contains more vapor, which is being sucked back into the underground tank so you're getting less gas for your money.

The only place that is correct is the State of California, but that can be bypassed by pulling back on the corrugated part.

US Gallon less than 3.8 Litres of not the best of fuel.  Ambient temperature Highs & lows in the US rather different from 

the UK,  so maybe we can forget about stuff about Yank Tanks filling station tanks.

Edited 14 December, 201411 yr by goneoffSKi

Weekly - I normally do about 400-500 each week so it works out about right.  I get the fuel warning light quite often in the winter, but not in the summer.  Just shows the difference in MPGs on winter diesel!

Or shows it takes longer each trip to get the engine to efficient operating temperature when it is colder, maybe never up to heat on short trips.

De-icing time,  rear screen and heated mirrors on, heater blower, lights on etc etc.

Then there is the balance of possible less friction/traction on cold road surfaces.

 

Some cars/engines run more economically in fresh cool air once coolant & oil is up to temperature will using 

winter grade Diesel or Petrol which really meets the same energy output per litre.

Let's keep it civil please.

Of course one could ramble on about the Specific Gravity and the purity of fuel affecting how much of your fuel is being lost or gained, but that would serve no useful purpose.   Let's just agree that the specific gravity in the UK is an average of 0.82.

Or shows it takes longer each trip to get the engine to efficient operating temperature when it is colder, maybe never up to heat on short trips.

De-icing time,  rear screen and heated mirrors on, heater blower, lights on etc etc.

Then there is the balance of possible less friction/traction on cold road surfaces.

 

Some cars/engines run more economically in fresh cool air once coolant & oil is up to temperature will using 

winter grade Diesel or Petrol which really meets the same energy output per litre.

 

tbh, I don't think much is different in terms of what I use in the car.  I de-ice before I start it, get in and go.  I always have my lights on when I drive regardless of season.  I would think air-con is the most draining on the battery, but I don't use that much when it's hot anyway.

 

It does take a long while to warm up though, and runs colder (according to oil temp) on the motorway.

 

Interesting ideas though.  Need to drop and email to mythbusters as I don't have the science in my brain or a big enough shed to test the theories of winter vs summer.

Mythbusters are 2 guys and their team in the US.

 

On Briskoda you have thousands of drivers with diesels & petrols, 

and dozens of threads over the years.

 

So all you need is people in the UK that get Winter Fuel between November & March but are in parts of the UK with not very cold 

weather, and they can check if modern cars really have much worse economy using the fuel for the 4-5 months of Winter,

but when it is not really cold.