In my "other life" I worked as a friefighter. One call that we constantly answered was car fires.
To this day I carry a fire extinguisher in my every day ride. I have assisted three people since and each time I managed to help save somebodys ride from a complete meltdown or worse.
One thing you have to remember when dealing with an engine fire is you really don't know what the fuel source for that fire is. Most times the fuel source is multiple. A shorted out electrical wire is burning off insulation, or has melted through a fuel line or is resting against a flammable
synthetic material in the engine compartment. Think about how much plastic is in a modern engine compartment these days.
Think twice before you open the hood with or without extinguisher in hand.
TURN OFF THE IGNITION FIRST.
By opening the hood you are accomplighing three things, one is access to the heat source. the second is you are venting the same heat source...giving it somewhere to go and INCREASING its "respiration". Third is you are supplying FRESH oxygen to a vented heat source which can easily turn into a blowover or a semi-explosive or explosive (depending upon fuel source) situation.
Any time I go after an engine fire with a extinguisher I hit it through the the grill and from underneath FIRST, the fire draws the retardent chemicals up into itself, then CRACK the hood and hit it again and keep hitting it until all flames are supressed. Wear LEATHER gloves (No synthetics) if you have them, a gasoline flareup is almost instantaneous, you have no chance to pull back and turn your face away, most chicks don't like the "hairless" look, no eyebrows, eyelashes, mustache or beard.
An engine fire is an extremely dangerous situation, gasoline, plastic,
oil, and big amperage from the battery, think about what you are going to do and the order in which you are going to do them. I saw more than a few do gooders climb into an ambulance with second and third degree burns simply because they were trying to help. Here is a good link to use when considering what extinguisher to install in your cobra.
http://www.h3r.com/products/c354ts_hv.htm
Mark