Skunky SHO BBQ Lessons (Page 2 of 2)

One questions for the Skunk Herder:

How much heat made it through the firewall, and what really worked vs. what didn't to patch the holes and feedthroughs?

So, my driver didn't report any "heat," but did say he saw "flames" in the cabin. I'll do some investigating tomorrow and see what it looks like inside.

I think the reason there may have been flames in the cabin is because of all of the fuel spraying about under the hood. Liquid fuel is going to migrate through even the smallest of holes. I have sheet metal patches over the large holes and various plugs in the smaller ones.

This has me seriously thinking about ways to completely seal the cabin from any future flame intrusion.
Unfortunately, that will likely only work in a situation like we faced. Throw in some contact with something large and heavy and the distortion to all of the structure will likely cause some gaps.

Lets be realistic, all we're really trying to do is buy the driver enough time to get out safely. As long as that happens the car can burn to the ground. I want to share a pint with them, not for them.

For the record, the Chotus does have a fire suppression system, for obvious reasons. One nozzle pointing at the Carb, one pointing at the Drivers crotch.

I believe these types of fire suppression are an inert gas, not a chemical powder..  They are widely used in all forms of racing..

Flames are drawn to the cockpit because it's lower pressure than the outside of a moving car.  On a fire like that one coming up the windshield even if there are no firewall holes, the fire is going to come around the windshield and through the open side window.  Not uncommon for it to come through the floor shifter for the same reason.  You can (and should) seal up everything you can but the lowest pressure area in the vicinity of a moving car is the inside of the windshield and fire will be drawn backwards, forwards, up and down towards that low pressure area if the fire is big enough.  Seems like there was video of a sedan racer where the engine blew up or something and took out an oil line.  The engine was in front but the fire trailed down under the car and then was sucked forwards to the driver through the rear hatch where there was no window.

I bought 2 of the 4 litre AFFF aqueous foam type fire systems from these guys http://www.racingfiresystems.com/Racing … stems.html and have them in the Imp and Mazda.  I got a deal of $600 by buying two.  They are not self refillable, Pegasus Racing refills them and sells the SPA system parts.  I haven't tried to see if the dude that recharges my extinguishers locally can recharge it.  I wanted to try to buy the parts to plumb the other cars and move the bottle from car to car but the parts almost cost the same as buying a system so I dropped it.  As far as a nozzle pointed at the driver, I've heard of the halon type causing people to hyperventilate from lack of air as halon displaces the oxygen in the area.  I also accidentally set off a 10lb powder extinguisher while rummaging around in the back of the van at 3am after an 9 hour drive from a Thunderhill race and I can assure you that is not a pleasant experience that ended when the powder stopped flying.  Between a choice of those two or coming out looking like the Stay-Puft marshmallow man (AFFF), I'll go with the latter.  But anything is better than nothing, burns are much more difficult (& expensive) to recover from than getting busted up.  Not an issue in SoCal but since the AFFF is water based, you need to bring it inside to keep it from freezing in some parts.  I believe that like beer, it stills works after getting frozen/thawed but isn't quite the same.

SPA's are recharged by SPA. Spendy if they are the electric fire type.
You get lots of bonus points for setting off any system on yourself. I have my bonus points already.

Most if not all of the Lemons cars originally had some form of OEM electric fuel pump cutoff from the factory.  On the Vortec V6 in the 484 LUV, the fuel pump relay is controlled by the engine computer, and runs only when the engine is cranking or running.  On the carbureted 4 cylinder in the 282 LUV, the fuel pump relay only closes when there is a tach signal.  We reused both these OEM fuel pump triggers when wiring the trucks for racing. 

I know that Fords have "extra" fuel cutoffs, like the notorious trunk-mounted impact sensor that shuts off the fuel pump every time you hit a pothole, so I can totally understand why a Ford team would wire directly to the fuel pump rather than reusing the factory wiring with all its finicky and unreliable cutoffs.  But this strategy only works if the kill switch actually gets used!

The fire bottle in the cockpit is only for putting out fires that are preventing you from getting out of the car.  I think CC's mandatory fire supression systems are overkill - just get the driver out of the car and then let it burn to the ground.