[TW]Fox;19990621 said:3mpg from not filling the tank?
my car would be roughly 25kg lighter with out the extra weight of 30 litres of petrol, wales is'nt the most level place to live and yes our hills/mountains do go down and not just up
Im just going by past experience of driving my car for year and half+
Are you saying that from experience, you save a significant amount of money through not filling the tank fully?
I have no idea of the circumstances in which the co2 ratings are done, but if they are on a full tank, then making the fuel tank much smaller would save a few co2.
Do cars have no mass on a rolling road?!On a rolling road, so probably makes virtually no difference to official figures.
Do cars have no mass on a rolling road?!
I tend to find similar but that's because i consciously think 'wahey, got a full tank' *stamp on pedal*
I think the rollers are set to provide a certain resistance based on standard kerb weight and air resistance figures to simulate real world conditions. How accurate that process is I have no idea.
Of course they do but they don't have to accelerate it because it stays in exactly the same spot whilst the wheels spin on the rollers.
Sure there might be a little bit of extra friction on the rollers but nothing massive, nothing that would even register a difference in economy or emissions figures.
I think the rollers are set to provide a certain resistance based on standard kerb weight and air resistance figures to simulate real world conditions. How accurate that process is I have no idea.
I tend to put £20-30 in at a time. If I fill the tank, I tend to do more unnecessary drives out at the weekend.
[TW]Fox;19989271 said:This sort of comment just boggles my mind.
HERESY[TW]Fox;19994535 said:Well I do really wacko things like brim my tank every time and use my brain to decide not to drive somewhere if I don't want to go or to calculate that I don't save money by visiting the petrol station 6 times a week or to grasp the incredible concept that £90 once a month is the same as £10 9 times a month.
But it seems I am in the minority.
I'm no physicist but my brain tells me that there are two key resistances to the motion of a car - air resistance and friction. Friction is the result of the weight of the car multiplied by the coeffecient of friction between the surface of the tyres and the 'road'. Friction is what makes heavier cars accelerator more slowly, so that "little bit of extra friction" is all that there is on the road; I don't think there are any other (significant) forces involved? If the rollers replicate the friction of a road surface weight is accounted for almost completely.Of course they do but they don't have to accelerate it because it stays in exactly the same spot whilst the wheels spin on the rollers.
Sure there might be a little bit of extra friction on the rollers but nothing massive, nothing that would even register a difference in economy or emissions figures.
Isn't filling up with 10/20 at a time the thing you do when you borrow your parents' car when you first pass your test and don't have a job? It's certainly not something that seems to have any benefit once you're a fully productive member of society.
My car is a Hybrid so if I had 25 litres of fuel in the car rather than 55 it would make a noticeable difference to my MPG say 3+mpg