Fire System Nozzle Placement

[arush]

I am in the process of installing a duel 10# fire bottle system that has 5 nozzles and would like to get your feedback on proper nozzle location and how you mounted the nozzles.   Any pictures would be greatly appreciated.
This is on a alcohol injected, Blown application.
I was thinking one nozzle on each side of the oil pan (on the outside of the diaper).
One nozzle on each side (front of motor) aimed at the heads and one nozzle inside aimed at my feet and torso.
I appreciate all responses.

[noslin]

great question, ill be in same boat soon.

[Paul New]

I run two nozzles at the front ont of the engine and two on the drivers compartment at my feet

[rooman]

Having been involved in Brendan Murry's 2007 Columbus incident I changed my thoughts on nozzle placement. When I built the Horan car that I drove in 2010 I put a pair of nozzles in the engine bay and a pair in the cockpit but I blanked the engine bay ones. As a fuel burner, Murry's case was a bit extreme but the chances of quelling a fire at speed in a front motor fuel car are somewhat slim and I decided that it would be better to protect the driver as much as possible. In Brendan's case the intake manifold left the scene and airflow over the exposed valley of the engine was sucking nitro diluted oil out of the crankcase and feeding the fire. An extreme case for sure but having all of the fire bottle contents aimed at the driver seemed like a better idea to me. At 235 mph the "breeze" is going to make it hard to keep the extinguishant in a place where it can actually work.  A possible alternate plan would be to put a nozzle (on a length of stainless flex line) in the diaper like some of the funny car guys and at least knock down an oil pan fire.

Roo

[Supercat]

We use 2 separate 10lb systems .
The primary is split between front of engine and drivers feet and knees.
Second system with 2nd arming plunger is 1 back of engine and 3 on driver. If the fire is still going when you stop and your primary system is empty it's nice to have the second system for exiting the car.

[glofria]

I've seen this before. Always go with what the OEM says to do. Here is what DJ Safety says: http://djsafety.com/wp-content/uploads/2016/10/10-lbs.jpg

In the case of fire suppression more nozzles is not better, but rather worse. a large (more) orifice yields less pressure and a shorter duration. Hence counter of what it is suppose to do.

Secondly these these systems are design to put out oil fires not fuel fires. That is what the fuel shut-off valve does. If you want more put a second system in as others have suggested.

BTW, we still have a halon fire bottle in our car. We tell our drive hit that button on our way out of the car. Luckily have never needed it.

[glofria]

That is one on either side of the frame rails under the headers shooting at the block and one for the driver shooting downward to his crotch area.

[arush]

Appreciate the feedback Paul, Roo, Supercat and Glofria.
All valid points to consider.
I am know thinking one in the diaper, two at the front of the engine and two in the drivers compartment aimed towards my feet.
I was not planning on going with a split system but do understand your logic.

[dreracecar]

You run a split system so that you dont dump two bottles if you hit one of them by accident. I have never seen a fire in the blown alc cars that we run in 25 years. I know of some racers that have one of the 10# blocked off and carry it as a spare just in case the first goes off and does not have to go find a replacement. If you hook up both, make sure you go out and spend another $700 on a spare set of bottles to keep in the trailer so that the SFI expires before you use them.