'How much further can you go on a tank of petrol?' blog discussion

treforsouthwell

A few random observations:

- The biggest money saver for most people is buying a car second hand, 3-year old or more. I don't understand why people buy a new car and then worry about the fuel costs!
- The traffic conditions and type of roads and top speed make the next biggest difference. Doing 60mph on a empty motorway might give you 60mpg while you might struggle to make 30mpg around town on a busy day.
- It's not clear to me that acceleration itself makes a big difference as this is an over simplification, actually it's two points:
a) If you accellerate and then brake you lose energy (the brakes is money down the drain)
b) Most cars have a fuel efficent rev band, if you stick in this band I don't think the actual accleration you use within it makes much difference (provided a is avoided).
- Finally petrol price varies quite a lot, our local ASDA is 114 while you can pay 130 at a motorway service station.

Bacchus_061

biggest difference for me was already driving within the speed limits and having the window closed

Paulgonnabedebtfree

30 mpg from diesel is about as good as it gets for me. But it is a 2.9 tonne van, is often heavily laden for work reasons and also needs roof bars and ladder on top. No way out of that really. Even so, I have still noticed a fair difference between driving like a prat and driving frugally. No scientific calculations but if I fill to the brim, it can mean the difference between about 440 miles and 495 miles between fill ups. I daren't run the gauge down too far because running out of fuel with a diesel is a lot more hassle than with petrol. I'm told too that the type of fuel pump I have can actually seize up because it needs the oil content in the diesel. They're pretty expensive pumps too.

Physio88

Its also important to remember that you should try to keep your fuel level above the 1/4 full level. Consistently running the gauge down to the red light before a refuel can damage the fuel pump on most vehicles as it can overheat and/or suck in all of the crap from the inner walls of the fuel tank. Using the 1/4 full level as a minimum or "time to refill" will help prevent wear and tear on other important parts and extend the life of your vehicle.

Also, contrary to popular belieft you will NOT waste fuel by filling up due to evaporation, a full tank actually helps decrease evaporation loss due to allowing less room for vapour to escape. :beer:

tomstickland

I've run tanks empty loads of times. I've also removed several tanks and there's never been any crap in them.

Oneday77

Physio88 wrote: »

Its also important to remember that you should try to keep your fuel level above the 1/4 full level. Consistently running the gauge down to the red light before a refuel can damage the fuel pump on most vehicles as it can overheat and/or suck in all of the crap from the inner walls of the fuel tank. Using the 1/4 full level as a minimum or "time to refill" will help prevent wear and tear on other important parts and extend the life of your vehicle.

Also, contrary to popular belieft you will NOT waste fuel by filling up due to evaporation, a full tank actually helps decrease evaporation loss due to allowing less room for vapour to escape. :beer:

Fuel filters help with tank sediment if there is any. A full tank increases the weight of a car so can increase consumption. So fo lots of shortish journeys try and keep the level relatively low. However if there are no cheap Fuel stations on your regular driving route you will waste fuel hunting to fill up.
For long runs just keep it filled, avoid stops on expensive motorway stations.

Oneday77

IAM driving is as all about making Safe Progress.
You do get shown how to travel along country roads at 60mph but only if safe to do so.
You brake less, anticipate more, position the car better and steer smoothly.
If more people did it the road would be a lot better.
The Observers ( they are not instructors) are all volunteers and have been through exactly what regular IAM members do and then get extra training. The sad thing is most people don't consider it until they are older. I am 33 and wish I had done it 15 years ago.

tomstickland

You brake less, anticipate more, position the car better and steer smoothly.

You can do those without IAM training too.

Sir_Alan

I run an 07 Mondeo 1.8 petrol. I don't know how accurate the fuel consumption readout is, but around town it generally shows about 35 mpg.

On my recent holiday in France, total mileage was 1600, much of it on autoroutes at the permitted 130 kph, and by the end of the holiday the reading had crept up to 40.2 mpg. Even the usual half hour crawl around Paris hardly affected it. I normally stay within the speed limit, but it was hot at times and I didn't hesitate to use the air conditioning when needed. All in all, pretty satisfactory.

I could check the reading by noting all mileages and litres, but I really CBA.

Physio88

50 litres of fuel weighs approximately 36 kg. An average family car weighs between 1000-1400 kg, larger saloons around 1600-1800 and 4x4s anything up to 3000kg. Therefore the actualy weight of fuel is between 1-3% of the cars actual weight (not including passengers). Having to make less stops because you have kept the tank full will more than compensate for the added weight. If you're worrying about this then you should also consider removing any unused seats and driving naked and dieting to save weight and fuel.

Yesterday 3:53 PM
tomstickland I've run tanks empty loads of times. I've also removed several tanks and there's never been any crap in them.

There is residue and sediment left behind due to impurities that can be sucked into the fuel pump and clog it (especially on older cars). The fuel is also used to help cool the fuel pump, you can even hear the fuel pump is louder on some cars as it has to work harder to suck in the fuel.