How much does your fuel weigh :confused:

[Kato]

Useless information unless you happen to be a crew chief making critical calculations ...But

Got into an odd conversation about weight vs performance, full tank vs empty etc; which ended up posing the question how much does petrol weigh, thought the answer would be simple, turns out it’s not.

Obviously, the bike will get lighter as the fuel is used and it seemed to me at the time that fuel for a given volume would be a constant weight, well actually it’s not that easy as the density of petrol varies greatly! The only constant being that 1 UK gallon = 4.546lts

A little research reveals the density range of petrol is between 710 to 775 gram/ litre at 15-degree Celsius. So we can deduce that the weight of 1 litre of petrol at 15-degree Celsius varies from 710 to 775 grams and therefore 1 gallon weighs in at somewhere between 3,227.66gms / 3,523.15gms a potential variance of 0.29549kg or just over ½ lb

So your bike could get heavier or in fact lighter just by swapping from Shell to BP the next time you fill up, food for thought thats all.

[Darkness]

Think how much heavier it used to be whilst it still had lead in it?



A large part of the range of densities is caused by thermal expansion. When it’s hot it gets bigger, but the mass doesn’t change, so it gets less dense.

You would expect Shell and BP to be at similar temperatures and densities on any given day where it is feasible to choose either.

[Bitza]

Meaning I guess that you get more fuel for your money by filling up on a cold day compared to a hot one?

[Kato]

Well no ...... you'll still be getting 5 ltrs of fuel it will just weigh + or -

When buying race fuel they quote specifics regardles of temp, premium product actually means that in this case

SUNOCO 260 GT = 761gms
Gulf Racing 102 unleaded = 756gms
Gulf Performance Plus = 734gms

[mickj]

Originally Posted by Bitza

Meaning I guess that you get more fuel for your money by filling up on a cold day compared to a hot one?

I would say yes, race teams that are a bit marginal on fuel often run the fuel through a cooler to increase capacity.

[slob]

just look at a motogp grid, space blankets round the tanks and forceps on the breather hoses

[Luddite]

Originally Posted by mjgt

I would say yes, race teams that are a bit marginal on fuel often run the fuel through a cooler to increase capacity.

That's right, Mick, although, like most things in racing, it's now regulated. For example, in MotoGP, since 2015, the fuel cannot be chilled more than 15⁰ C below ambient temperature. There must also be an overflow tank to cater for expansion with a non-return valve. That means any fuel expelled from the tank on the grid due to expansion is lost, hence the use of forceps mentioned by slob.

[crawsue]

Don’t want to hijack an interesting thread, but topping up my 1959 Matchless G80 yesterday at my local Esso station I noticed the pumps had been re badged, normal Esso 95 ron. now contains 10% ethanol, Esso supreme, 5%....I honestly didnt perceive any difference in performance....although with an old British thumper it’s difficult to use the word “performance “ in any meaningful discussion.

[Darkness]

Originally Posted by crawsue

Don’t want to hijack an interesting thread, but topping up my 1959 Matchless G80 yesterday at my local Esso station I noticed the pumps had been re badged, normal Esso 95 ron. now contains 10% ethanol, Esso supreme, 5%....I honestly didnt perceive any difference in performance....although with an old British thumper it’s difficult to use the word “performance “ in any meaningful discussion.

Has anyone enquired whether it actually contains 10% ethanol, or less than 10%?

I thought e10 was being rolled out in September, so they may be getting the pumps ready for it.

[Luddite]

Originally Posted by Darkness

Has anyone enquired whether it actually contains 10% ethanol, or less than 10%?

I thought e10 was being rolled out in September, so they may be getting the pumps ready for it.

It could be as low as 5.5%.

I've posted a reply to this in http://www.ukmonster.co.uk/monster/s...d.php?p=588637

to keep all the ethanol stuff in one place.

[Dirty]

Good reason to get bigger inlets and drive it like you stole it. Use up all that pesky dead weight quicker.

[mickj]

Originally Posted by Darkness

Has anyone enquired whether it actually contains 10% ethanol, or less than 10%?

I thought e10 was being rolled out in September, so they may be getting the pumps ready for it.

I noticed the same warning on fuel pumps in Bridgewater yesterday. It is effective form Aug 1 and don't forget it's up to 10% so it could be anything.

[crawsue]

Strangely, I refuelled at Tesco/Esso at Dumfries yesterday,it’s a very busy outlet ,their 95 ron Esso was showing 5% ....but the roll-out is underway.....