LPG is produced during the normal petrol chemical distilling process of crude oil and the letters LPG stand for Liquefied Petroleum Gas, so in other words - petrol gas - which is 100% octane as in 100% octane 5* petrol 97/98 4* and 97 super unleaded. Any car can run on high octane fuel without modification, problems arise from cars designed to run on high octane being asked to use regular unleaded, which is 94%. LPG is stored in a liquid form because being 250x more dense than as a gas it requires less space within the car. Many manufacturers, including Renault, Citroen and Vauxhall offer LP gas cars direct from the dealership as part of the range. Other manufacturers such as Ford, Range Rover and Chrysler may not have an LPG vehicle as part of the range but will allow conversions to be carried out after manufacture.
Interestingly two of the largest nations for LPG use in vehicles are Italy and Japan, who are not oil producers. In the UK we produce in excess of 4 million tonnes per