Did you know that Optimax can if left too long in starage drop in it's RON values ??? Check this out....

 

http://www.shelloptimax.co.uk/jive3/thread.jspa?forumID=1&threadID=509&tstart=0

 

http://www.shelloptimax.co.uk/jive3/thread.jspa?forumID=1&threadID=250&tstart=15

 

 

Also posting on these threads is an expert from Shell.

Drops the second it leaves the refinary :S

I heard modern petrol is more susceptible to 'going off' than petrol was ten or twenty years ago.

Did you know that Optimax can if left too long in starage drop in it's RON values ??? Check this out....

 

http://www.shelloptimax.co.uk/jive3/thread.jspa?forumID=1&threadID=509&tstart=0

 

http://www.shelloptimax.co.uk/jive3/thread.jspa?forumID=1&threadID=250&tstart=15

 

 

Also posting on these threads is an expert from Shell.

 

i think any petrol does m8;)

after leaving my jag in storage for a winter with a full tank of juice, it ran like a bag of spanners, dropped the old petrol topped up again and it cured any pinking, so deffo an idea for those who park the zx up for winter, is to empty the tank

Yes that's right - all petrol "goes off". Its a very complex blend of chemicals. Two major changes over the years 1) the removal of tetra-ethyl lead (thank God) and a new BS which allowed more volatile octane enhancers. To get the octane level right you either add a large amount of a not-very-volatile additive or a small amount of a very volatile one. This latter is cheaper so guess what they do?

 

Because it's more volatile, it evaporates more quickly and hence the remaining petrol's octane level goes down.

 

Oh and bike carburettors freeze up = "carb icing".