Firewall to Trunk

SCrazy

SCCoA Member
As part of my roll bar installation I'm deleting my back seat and making a panel out of aluminum to block off the rear of the seat. If it's not a huge pain I would like to make that panel meet the requirements for a fire wall.

I see the rules specify the thickness of the aluminum needed but I do not see where they discuss how tight fitting or sealed the thing needs to be.

I'm thinking a flat panel where the rear seat used to be covered with some cheapo carpet or something but out at the far ends where the quarter panel is behind the plastic trim panels could be a nightmare if the aluminum needed to be carried all the way out there and if it needed to be sealed up tight.

Just wonding exactly what constitutes a "Fire Wall"
 
For it to truly pass NHRA tech, it needs to be sealed. It takes a little work due to all the wiring running through there, but it isn't particularly difficult. The package shelf needs to be sealed as well.

All that being said, my firewall was inspected for the first time just recently during the most intensive tech in I've ever experienced. Up until then, the most that any inspector had done over the past seven years was just take a glance at it through the trunk.
 
Would a standard seam sealer be considered sealed for any minor gaps or holes? Or would a product like an intumescent fire calc used in the construction industry be more appropriate?

What is the ultimate purpose of the barrier. To seal fuel and battery fumes from reaching the cabin? To contain a fire in the trunk for a period of time? To restrict a flash fire from blowing directly into the cabin?

Seems like based on its purpose the construction of the fire wall could vary greatly.
 
Would a standard seam sealer be considered sealed for any minor gaps or holes? Or would a product like an intumescent fire calc used in the construction industry be more appropriate?

What is the ultimate purpose of the barrier. To seal fuel and battery fumes from reaching the cabin? To contain a fire in the trunk for a period of time? To restrict a flash fire from blowing directly into the cabin?

Seems like based on its purpose the construction of the fire wall could vary greatly.

That would be interesting to know. I dont have any wiring going through the panal but the rear braces go through it. I will tell you that the car will have more road noise. Something I dont like as much.

Ken
 
I don't know the ins and outs of the firewall. But I used dum dum to seal the panel in my dads marauder.

I would also like to know what it is supposed to keep out of the driver compartment.
 
Sounds like the construction requirements are pretty loose, I'm going to go ahead and put it in and seal things up with seam sealer as best as I can.

The actual purpose of the thing is an interesting intellectual question though.
 
Brian, seam sealer should be fine. I used thin foam weatherstrip tape on mine, and the tech inspector had no issue with that. As far as purpose, I can't say for certain. As I understand it, the point is to prevent fumes from passing into the cabin from the trunk, as well as preventing a trunk fire from reaching the cabin for a short period of time. But that's just my assumption.
 
by any chance do you have any pictures of how you sealed the package shelf? I need to build my firewall as well and would like to keep my factory amp and sub just so I have some tunes when I drive.
 
All that stuff is gone in my car. The big speaker openings will have a piece of aluminum and the smaller screw holes etc will get a dab of fire calc.

I don't have speakers or any of those amps/modules that were mounted in a tray under the baggage shelf.
 
Same here. The factory stuff is long gone. I sealed the holes up with the same aluminum that I used to make the firewall.
 
so do either one of you guys have a radio in your car? I know eventually when my car is a pure track car I will ditch the radio and all the creature comforts but not something I really want to do at this point. After looking in the garage I see that rod has his subs in the spare tire area but since I have a fuel cell that really isn't an option just trying to get some ideas for speaker placement and following NHRA rules for the firewall. I guess I might just have to go to the drawing board :rolleyes:
 
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I took my radio out at the moment. But there are speakers in the doors still. I don't drive on the street much so it was never on anyway and it was a dvd player with touch screen. A little much for a drag mostly car.

Just have speakers in the doors and quarter panels. I have some nice seperates that have good bass to them. Its not booming bass but its good.
 
so do either one of you guys have a radio in your car? I know eventually when my car is a pure track car I will ditch the radio and all the creature comforts but not something I really want to do at this point. After looking in the garage I see that rod has his subs in the spare tire area but since I have a fuel cell that really isn't an option just trying to get some ideas for speaker placement and following NHRA rules for the firewall. I guess I might just have to go to the drawing board :rolleyes:

I'm listening to a different kind of music when I'm in my car.
 
I hardly ever turn the stereo on, but yes, the car has aftermarket speakers, tweeters, subs, amps, head unit, etc.
 
After a bunch more research I think I've answered all of my questions about the fire wall construction.

The firewall is intended to accomplish 3 things.

First obviously to slow the spread of fire through the car. There is no standard like in the construciton industry that talks about how long it is supposed block the spread of the fire just simply that it is.

Second in the event of a liquid spill (fuel) in the trunk it is supposed to block the flow of liquids into the drivers compartment.

Thirds in the event of a small fuel leak or battery off gasing it is supposed to block the spread of fumes from the trunk into the drivers compartment.

Needless to say that is asking alot. What I've decided to do is to construct an aluminum firewall that is as close fitting as possible where the old seat back was and to place aluminum patches over any large holes in the baggage tray. Then I will use 3M Intumescent fire calc to seal all the edges of the fire wall, patches and any small holes. Then I will use 3M expanding intumescent fire foam to fill any larger voids.

There are kits for sale with fire calc and foam marketed expressly for automotive fire wall applications but the products sold in the kits appear to have the same specifications as products you can buy off the self at Home Depot for about 1/4 the cost.
 
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