The only problem is with a full size extinguisher is that its gonna wiegh like 10-15kg's+ alittle bit too much wieght to lug around at least with a mid sized extinguisher designed for Automotive use it will help a bit!! But then again judging by how big the flames are and the fact that there is petrol as a major factor would you really want to risk being that close to the eingine bay!!?? I say get full comprehensive insurance and keep your self, your mates and your loved ones safe and JUST RUN and let it burn to the ground cos your gonna get paid out for the damage any way!!!!