Landracing Forum
Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: BB2_Ed on June 09, 2008, 01:19:43 PM
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I know the Rule book in section 3.F States that the firewall must be Metal, and .060" thick.
I remember in a conversation with a tech inspector (can't remember who) that it should be .060" thick if Steel, or .095" thick if Aluminum?
Is this just good advice, or a rule?
I cannot find any mention of it anywhere else in the rule book, and I have also searched this forum for this answer. Ready to order the new aluminum and would like to confirm the thickness requirement before I place my order.
Thanks.
Ed Hillstrom
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Go with the .095 Aluminum. Makes it stronger for mounting any other hardware etc. on. Also better protection
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3.F requires .060. Recomends .095. Up to you.
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MY car has a 7/16 fibergalss firewall and I overlayed it with form fitting, seamless 12 Guage Aluminum Sheet Metal. when I mic'd the 12 ga sheet it only measure out to .081
I guess that is 33% thicker than the minimum .060 but less than the suggested .095
I then shot 3 coats of Lizard Skin Ceramic heat shielding on it (that stuff is good, not totaly fire proof but really resists heat and flame) also shot the Lizard skin in 3 coats on the entire floor and 2 coats on the doors, sides and roof.
Charles
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Sounds like you are very well protected, and legal. Good idea with lizzard skin on both sides!
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NHRA just passed a rule that all funny cars be sprayed with a fire resistant coating on the underside of the bodies. Lots of fires lately have caused concern and it's a good rule. If you have a fiberglass or carbon fiber vehicle this might be worth looking into.
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Glen, That is also what I heard. I did not spray the underside of my body, but I did spray the complete inside.
Let me tell you, I was sold on this Lizard Skin Ceramic when I saw the guy at the rod shop put a propane torch to the aluminum side of a sheet coated with 3 coats of this stuff, for a full minute he put the flame to it, then he put his bare hands against the coated side of the sheeting.. It was warm but not hot. I felt it and to my surprise it was not a trick it was warm but not hot...
A 2 gallon bucket of this stuff runs about $190 but it will coat the average car no problem,, I had enough to put two coats on the roof (more for heat insulation than fire up there).
Charles
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That Lizard Skin sounds good think i'll look into it, as our front end and hood is fiberglass.
Any body know what the drag racers are using?
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On my roadster I am using aluminum coated fiberglasses cloth on the panels in areas where I think a fire may happen. Its all a guessing game that I don't want to prove. I don't know who makes it though, I got a roll of it from one of the shops at Indy.
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This makes sense for glass bodied cars if you watched Cruz Pedregon knock the body off his funny car recently when the fire was inside the car. When the body flew off it continued to burn but the chassis fire went out pretty quick.
DW
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DW, that is exactly what I was thinking. any extra bit of heat or flame protection is a good idea.
Charles
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I thought intumescent (expands when heated) paint was an NHRA reqirement for funny car bodies for some time now. We have fire retardant paint on the inside of the roadster body. It has been there for so long I forget who made it. I think Ken got it from a funny car owner he was crewing for.
Jim
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While it may be legal, an aluminum firewall is not much protection from a sustained fire-- the melting point of AL is simply not that high. Mild steel is a far better proposition and a sheet of stainless steel wouldn't be bad, either. I scored a few sheets of Inconel on the surplus market for my firewall. It's used in jet engines so its heat resistance is well established.
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While it may be legal, an aluminum firewall is not much protection from a sustained fire-- the melting point of AL is simply not that high. Mild steel is a far better proposition and a sheet of stainless steel wouldn't be bad, either. I scored a few sheets of Inconel on the surplus market for my firewall. It's used in jet engines so its heat resistance is well established.
The Proper thickness Aluminum firewall is fine.
J
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Thanx, noonan. Methinx all were getting a bit OVERWORKED with the topic.
But, with that said, BUY THE BEST SAFETY EQUIPMENT YOU CAN AFFORD, to CYA's (literally).
Ya don't want to make a chitlin of yerself!
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The Proper thickness Aluminum firewall is fine.
J
Yes it is or the rule would be changed, but as IB has also stated, the is you that must decide if you need additional protection. Your Fire system should also be factored in to your decision.
be safe, have fun, go fast
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Manta2,
Have you tried to cut the Inconel yet? If it is .060 you have better have a good shear and don't even get it close to a band saw, it will kill the blades right now. It does have some nice properties though, at 1800 deg F it is stronger than mild steel at room temp!! I have made some turbo collectors from it, real pain in the ass to work with. What Inconel alloy do you have 625 and 7-18 are the most common.
Rex
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Manta2,
Have you tried to cut the Inconel yet? If it is .060 you have better have a good shear and don't even get it close to a band saw, it will kill the blades right now. It does have some nice properties though, at 1800 deg F it is stronger than mild steel at room temp!! I have made some turbo collectors from it, real pain in the ass to work with. What Inconel alloy do you have 625 and 7-18 are the most common.
Rex
it will slice up nicely with a plasma cutter
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Rex;
I just looked on the Inconel- it is marked "718". As pointed out in a post by "Stainless1" it cuts nicely with a plasma cutter. Exotic alloys are usually a PITA to cut but in sheet form a plasma cutter can handle it.
I wouldn't trust an aluminum firewall; I've seen too many fires where the aluminum parts were melted, even the aluminum centers out of wheels. If a fire is extinguished quickly an aluminum firewall will hold up to the high heat but if it isn't and you're not able to exit the car quickly........you're toast.
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I don't know about metalurgy (or much else either). But a couple of years ago I was talking to Earl Wooden about a recent run in his streamliner. He had the zoot-zoot carbon fiber brakes. Well, anyway, he aborted a run (hope that's politcally correct) and hit the brakes. Boy, I guess it stopped. But the heat from the brakes melted the wheel weights and fried the tires. Maybe he could have taken a little longer to stop, but they sure worked well. Any way, he was embarassed having stopped on the course, decided to restart and get off there before Glenn gave him hell. Restarted, put it in gear and fried the clutch, too, as everything was locked up.
I still haven't got us some carbon fiber (fibre?) brakes. Seems these slow roadsters stop pretty well by just letting off the throttle.
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Stan, that is Aero Braking, and off topic, but with any luck someone will start a thread on that wihin the next 24 hours... as long as no one asks about it...