Great info Bro_Gill you obviously have earned your stripes with this stuff. All this input is being compiled and I believe a post with all this info/data is in order. Thanks againReality is, you probably need to service the system after every race. Not because the system is bad, but because of the type of abuse desert racing applies to it. From silt and dust entering ports to the thin wall tubing they use that can easily be smashed to prevent proper movement of the extinguishing agent. They need an inspection. For tips on making a good system, keep the runs from the bottle to the nozzles as short as possible. If given a choice, use a larger size tube (diameter) to supply the heads. As far as auto vs. manual activation, I would prefer manual as there are plenty of ways for an auto system to activate without fire in a desert car. Place the manual activation button/pull within easy access of both driver and passenger and anyone who would come up from outside to help.
As to the system you have in your current ride, if it is a single nozzle system and it is in the engine compartment area, and auto activation, you probably had an activation caused by high temps during your race that you weren't aware of. And, not attacking you, but having it only in the engine compartment, you were doing it wrong. These things are not designed to put out fires, they are designed to by the occupants time to get out. If you only have one nozzle, it should be between you and the fuel cell. Other than name and type of extinguishing agent chosen by the purchaser, these systems are all very similar in design and operation. One thing you should know, Halon is an air dispersing agent as well as a chemical reaction inhibitor. While use in an open car like a SxS probably wouldn't harm you, the agent does displace oxygen and is not recommended for occupied spaces prior to use. I have always preferred a wetting agent when it comes to auto applications because it cools the surfaces while extinguishing the fire. Halon will stop the current flames, but after, if surfaces are still hot, any remaining fuel vapors will reignite.