Making a Rear fire wall, help please
#1250372
06/13/12 10:46 AM
06/13/12 10:46 AM
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Joined: Dec 2006
Posts: 1,178
Indy
FlyFish
OP
super stock
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OP
super stock
Joined: Dec 2006
Posts: 1,178
Indy
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I’m putting a fuel cell in my trunk, so I guess it is time to put in a rear fire wall (I assume it is an NHRA requirement, but I have never checked). My question is, what materials do most folks use for the fire wall (aluminum, thin sheet metal, etc,), where did you find said materials, and how did you make it?
I’m thinking of just starting with a piece of cardboard to make a template from the back seat area, but I was not sure where to get the metal (or what kind).
Thanks in advance for any help or pointers you have.
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
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Re: Making a Rear fire wall, help please
[Re: FlyFish]
#1250373
06/13/12 11:15 AM
06/13/12 11:15 AM
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Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
ProStDodge
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master
Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
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from the rule book: Quote:
FUEL SYSTEM
All fuel-tank filler necks located inside trunk must have filler neck vented to outside of body. Vented caps prohibited. All batteries, fuel lines, fuel pumps, or filler necks located inside trunk require complete bulkhead of at least .024-inch steel or .032-inch aluminum to isolate driver compartment from trunk. Fuel lines must be located outside driver compartment. Fuel tanks must be within confines of the body. see general regulations 1.5
The cardboard cutout is a good way to start. Usually you can find a suitable piece of steel or aluminum at a store such as Menards, Lowes, Home depot, Rural King, Farm & Fleet, etc..
Don't forget to patch the holes in the rear package shelf with metal as well (speaker and defrost vent holes).
also Check the lines I put in bold from the fuel tank portion of the rule book.
Quote:
General Regulations 1.5
Tanks: When permitted by class regulations, fuel tanks located outside body and/or frame must be enclosed in a steel tube frame constructed of minimum 1 1/4-inch O.D. x .058 chromoly or .118 mild steel tubing. All fuel tanks must be isolated from the driver’s compartment by a firewall, completely sealed to prevent any fuel from entering the driver’s compartment. All fuel tanks must have a pressure cap and be vented outside of body. A positive-locking screw-on fuel tank cap is mandatory on all open-bodied cars. Insulated fuel tanks prohibited. When used, fuel cells must have a metal box protecting the part of the fuel cell that is outside of body lines or trunk floor, excluding hose connection area in rear. The metal box must be constructed of minimum .024 steel or .032 aluminum. Nonmetallic fuel cells or tanks must be grounded to frame.
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Re: Making a Rear fire wall, help please
[Re: ProStDodge]
#1250375
06/13/12 11:24 AM
06/13/12 11:24 AM
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Joined: May 2011
Posts: 4,489
northern,Ohio,USA
Clanton
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Like said i made a template of caedboard/posterboard taped togather and then went to aluminum and i screwed the final product to the floor,seat support,hammered over the hook for the rear back seat.
Last edited by Clanton; 06/13/12 11:35 AM.
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Re: Making a Rear fire wall, help please
[Re: Clanton]
#1250376
06/13/12 11:34 AM
06/13/12 11:34 AM
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Joined: May 2011
Posts: 4,489
northern,Ohio,USA
Clanton
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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not the best job but passed tech no problem.I called the tech at the track i go to to make sure what i was doing would pass. PS: Yes i messedup on the seam with an arch being there and i used the streight edge of the sheet of aluminum [4x8]  the 4x8 is not big enough to get both cuts from and i was making a console at the time also so i had several sheets that were about 20$ each.
Last edited by Clanton; 06/13/12 11:43 AM.
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Re: Making a Rear fire wall, help please
[Re: ProStDodge]
#1250377
06/13/12 11:45 AM
06/13/12 11:45 AM
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Joined: Dec 2006
Posts: 1,178
Indy
FlyFish
OP
super stock
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OP
super stock
Joined: Dec 2006
Posts: 1,178
Indy
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Quote:
.........
Don't forget to patch the holes in the rear package shelf with metal as well (speaker and defrost vent holes)............
 , yup, I remember you saying that at MMW last year in Indy. Thanks for the quotes from the rule book, I want to make sure I have this thing legal.
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
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Re: Making a Rear fire wall, help please
[Re: ProStDodge]
#1250379
06/13/12 12:25 PM
06/13/12 12:25 PM
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Joined: Oct 2007
Posts: 4,207
New York
polyspheric
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Joined: Oct 2007
Posts: 4,207
New York
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completely sealed to prevent any fuel from entering the driver’s compartment
Passes tech? Depends on how busy they are. "Sealed" means liquid cannot pass through the seam, so sheet metal screws, etc. are not legal.
A better question: if it's not completely welded or tightly riveted, what material is acceptable as a gasket? Obviously, not something soluble in fuel, but how about seam sealer (like for body work), window caulk, form-a-gasket???
Boffin Emeritus
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Re: Making a Rear fire wall, help please
[Re: polyspheric]
#1250381
06/13/12 12:51 PM
06/13/12 12:51 PM
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Joined: May 2011
Posts: 4,489
northern,Ohio,USA
Clanton
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Quote:
completely sealed to prevent any fuel from entering the driver’s compartment
Passes tech? Depends on how busy they are. "Sealed" means liquid cannot pass through the seam, so sheet metal screws, etc. are not legal.
A better question: if it's not completely welded or tightly riveted, what material is acceptable as a gasket? Obviously, not something soluble in fuel, but how about seam sealer (like for body work), window caulk, form-a-gasket???
PS: i correct myself that smoke can get past the wheel tubs and still have the trunk sealed but in my opinion that is not likely the case.just saying.
OK so if water can not get past the barrier than how does the smoke enter the driver area?!!!!!!!!!!!! 
Last edited by Clanton; 06/13/12 01:02 PM.
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Re: Making a Rear fire wall, help please
[Re: Clanton]
#1250382
06/13/12 03:34 PM
06/13/12 03:34 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Master
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Posts: 52,972
Romeo MI
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Quote:
Quote:
completely sealed to prevent any fuel from entering the driver’s compartment
Passes tech? Depends on how busy they are. "Sealed" means liquid cannot pass through the seam, so sheet metal screws, etc. are not legal.
A better question: if it's not completely welded or tightly riveted, what material is acceptable as a gasket? Obviously, not something soluble in fuel, but how about seam sealer (like for body work), window caulk, form-a-gasket???
PS: i correct myself that smoke can get past the wheel tubs and still have the trunk sealed but in my opinion that is not likely the case.just saying.
OK so if water can not get past the barrier than how does the smoke enter the driver area?!!!!!!!!!!!!
Up the C-post... I filled mine with expanding foam
works great... I sealed my rear firewall area around
the tubbs with fuel resistant silicone... most people
wont buy it due to the cost but I had some from work
(8oz tube is $120)... I use to buy it by the cases
for the lab
Also my tank isnt in the trunk(dont have one) so
the alum goes across the top of the cell... open
on the bottom to the ground
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Re: Making a Rear fire wall, help please
[Re: FlyFish]
#1250385
06/14/12 06:39 PM
06/14/12 06:39 PM
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Joined: Jun 2008
Posts: 186
Middleton, ID
curleysracecars
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member
Joined: Jun 2008
Posts: 186
Middleton, ID
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Carboard is your friend. I can buy flat sheets from a local shipping supply company for about $6. Cut it up, and make multiple individual pieces if need be. If you too much away in a small place or something...dont toss it. Take masking tape to fill in the void where the cardboard was cut too much. Once you are comfortable, I will usually transfer all modifications to a new fresh piece of cardboard and cut it out to make sure everything is kosher. From there, I go on to using .040 aluminum. (Use 5052 series material if you intend on bending it).
When a template is done, it looks like a novel...I have notes written all over it. "Add 1/8" here", etc. Good luck. Remember cardboard is cheap...so get the template perfect.
Kyle Curley
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