economically speeding is it better to fill up your car petrol or do it weekly?

[slartybartfast]

any thoughts

aarhg,
i wish i could edit this

economically speaking is it better to fill up your car with petrol or put in a set amount weekly.

is what i meant

Unless it's likely to get syphoned, I can't see it making any difference.

i suppose a full tank of petrol weighs more than just half and as such would use more fuel

It wouldn't make that much difference would it?

You'd still be going the same amount of miles.

Unless you're taking into account that it's heavier when full of petrol, or that you might drive further to get the petrol.

with the prices going up so much, i thougth, perhaps buy it before it goes up yet again

DH will only half fill ours as he says when it's full you're carrying the weight of the full tank, therefore burning petrol quicker.

'with the prices going up so much, i thougth, perhaps buy it before it goes up yet again'

that's awful isn't it, I suppose with it going up about a penny a week...

every penny counts zigzag

I take the view that with the price it is, you are putting half the money in your tank rather than leaving it in your bank account. I fill up around £25 about every week to ten days unless I am going on a long journey.

tank half full is best as if you fill right up the car uses more because it is heavier,also don't let it go down to empty as you will get all the dirt coming through.

I do a fair amount of driving so if I didn't fill up every time I would be down at the garage every few days. I find getting petrol a bit of a chore so try to do it as infrequently as possible.

One of the towns about 12 miles from my home has fuel at several pence cheaper than in my local area. So if I'm in that town I always aim to fill up.

Otherwise I just fill-up to the top as soon as I'm down to about 1/4 of a tank and am near a petrol station which is a reasonable price (use www.Petrolprices.com to get a feel for which stations tend to be lower than others).

do you use the car less or drive more economically if you know you have a set limit?

we try to use it less but unexpected things happenn

I hate filling up - such a dreary task, so I always get a tankful.

I couldn't be doing with going to the garage more frequently than I have to

Er... Petrol doesn't weigh that much.

1 litre of petrol weighs 737g so if you had a 50 litre tank it would weigh 36.85kg when full - if you're bothered about the weight of the fuel then you'd better not put passengers in the car!

Also, fuel is sold by volume so you get slightly more if you fill up on a cold morning than on a warm afternoon.

Petrol's a volatile liquid so again, you'll lose a small amount as vapour each time you open the tank (not sure whether either of these are significant though)

That's cunning, CokeFan.

The other thing to consider is that unless the petrol station is literally on the route of somewhere you are going anyway, any savings you might make through having a lighter car would be more than used up by the "waste" of the extra fuel used getting to the petrol station.

Wow CokeFan I'm impressed!

Depends if you buy an extra choccie bar/magazine/drink each time you go to get petrol

By the way OP I thought your original thread title was fascinating: economically speeding - cool!

I think Jeremy Clarkson also mentioned the "fill up when cold" fact when he did the "London to Edinburgh return trip on one tank" challenge.

To get the coldest fuel into your tank, I think the best strategy is to:

1. Pick the pump furthest from the underground storage tank, and hence with the longest pipe.

1. Pick a time at some ungodly hour in the morning say 4-5am, when it is cold and when the fuel is most likely to have spent the most time in the pipes which are much colder (certainly in winter) than the well insulated storage tank.

1. Only fill with a volume equivalent to the supply pipes (say 5-6 litre at a guess).

1. Repeat at the other pumps.

1. Pay the very confused attendant for the multiple deposits.

1. Adopt a smug demeanour at your 20-30p saving.

Do Viz still have that "suggestions page" ?