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Discussion Starter #1 (Edited)
I've been all through my IHRA rule book and all I've found is that a "shielding" is required on all rear engine cars where the brake line passes the engine area. Can any one elaborate on what is actually accepted?? Tube wall thickness? Scotch Tape? Bubble gum? The wording is pretty vague. I was going to just put the line in the lower chassis tube, entering at the master and 'doubling' the tube intrusion with a "tube blister", but I'm having second thoughts now. Thanks.
Rob
 

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I'm not a dragster guy. But I think most with a rear engine setup just run the brake line inside the upper or lower rear digger main frame rail & use the frame tubing it's self as the "shield".


And on full chassis door cars if the front brake line is attached to the outside surface of the front frame rail, (on the side facing the engine/drivetrain) I have seen a few guys just use a short length of 1/2" or 3/4" OD x .065" or .058" wall tubing as a brake line shield. And others have just taken the easy route & rotated the brake line around to the other face of the frame rail (away from the engine drivetrain) & not used a shield. And of course just like a digger combo, putting the brake line inside the front frame tubing on a door car is an option too. But depending on how the door car front chassis is designed it may be kinda hard to do.
 

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Discussion Starter #3
I'm not a dragster guy. But I think most with a rear engine setup just run the brake line inside the upper or lower rear digger main frame rail & use the frame tubing it's self as the "shield".


And on full chassis door cars if the front brake line is attached to the outside surface of the front frame rail, (on the side facing the engine/drivetrain) I have seen a few guys just use a short length of 1/2" or 3/4" OD x .065" or .058" wall tubing as a brake line shield. And others have just taken the easy route & rotated the brake line around to the other face of the frame rail (away from the engine drivetrain) & not used a shield. And of course just like a digger combo, putting the brake line inside the front frame tubing on a door car is an option too. But depending on how the door car front chassis is designed it may be kinda hard to do.
Thanks for the feed back Dave. My intention was to run the line inside the lower tube because it runs the length of the car and exits below the diff right where I'd need it to hook up to the Tee. My concern is comprimising the structural integrity of the lower tube. I'm thinking that the doubling "blister" should take care of any weakening that the hole may make.
Has any one actually used one of these 'blisters'?
Vandy?
Rob
 

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The NHRA rule book says this about reinforcing any hole in an SFI chassis......

"Reinforcement must be of at least the same cross sectional area as the hole, at least .049-inch-thick chromoly and completely welded around the outside."

This reinforcement method applys to everything from "small" to "large" holes in the chassis. But doesn't apply to any "micro" pin holes drilled in assorted chassis tubes that let hot expanding gasses escape during welding to help prevent weld puddle blow-out.

 
I have seen hole reinforcement done this way many times (call it a hole "patch, or ring, or blister, or doubler", or whatever). But I have also seen another method where some have instead used a small piece of tubing welded over the chassis hole at an angle forming a "Y" off-shoot from the main tube. Even though the second method would reinforce the hole I don't know if it would be legal/acceped like the first method is.
 

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Discussion Starter #5
Thanks for looking that up Dave.
Logically I would think that a cross sectional match to the hole and a thickness the same as the tube wall would be what is needed.
I suppose that I should renew my membership and get an updated rule book sometime soon lol.
Thanks again.
Rob
 
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