Australia's P/B ratio is pretty static all year round because the country doesn't have the huge temp variations that other locations on this fine planet do. Sure we get from, for example, -10C to +45c but not all over the country and we certainly don't get the -40s to +50s other countries do. Kinda makes me glad I'm where I am cause I know I couldn't survive something like a Siberian winter.
and where i am ,, Perth .. oz .. ..just had a long spell at 38-44 C
.. and it has its own issues whereby running maxed cooling systems at 95 C +... for some in depth reason... may concentrate end heavies from the fuel in the convertor
a whole new topic i expect !!
the law in aus actually allows for considerable margin in the ratios and a lowly minimal octane standard
the economics and logistics of supply markets ensure high quality west australian gas shelf condensate is shared only to west australians.. but due to the width in the standard is watered down with butane waste from the petro refinery in kwinana .. and sold at full saudi price.. even though its a waste stream oversupplied into a tiny market
usually the quality is higher than the rest of the country.. in small servos with limited acess for a large truck,, they still get straight propane from the truck that fills the camping store vessels
the eastern seaboard gets LPG imported from singapore,, sourced from many places and has considerable butane content .. due to the nature of how its sourced then the ratio is subject to seasonal variations
.. its quality is generally lower than western australia ( higher butane ratio )
the propane has a lower fuel density.. higher ratios of propane will not get as far,, litre per litre.. to those with higher butane content
butane tends to lower the octane.. propane pushes it up
butane tends to have issues below certain ambient temps with cold start vapourisation .. hence seasonal variation in some markets that are not torrid climate
