SFI 25.5 Roll Cage Help

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MidTexCuda

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Ok i finally broke down and ordered my SFI 25.5C booklet for my new cage and man people were not kidding about the book being confusing and not very helpful (other than the funny car cage). I am looking for input.

Question : Can i use the stock door sill structure to attach my forward and rearward cross members and X brace the door or will i need to tie the front and rear cross member together with a tube instead of the stock sill? (note the stock floor is gone)

Also i was planning to make a tube structure around my mid plate and attach the horizontal dash bars to it. Is this allowed?
 
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I don't get what you are asking.
sorry i said sill i meant the stock rocker on the door.
IMG_1422.jpg
 
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You need to call your division tech director. Write down his name and keep notes. Make sure they explain it to you in detail.

I had to redo a bunch of stuff because no one could agree on how much of something was enough. You are in the same boat. NHRA has an issue with clarity. Their drawings are half assed.
 
I don't have the 25.5c specs in front of me but at a minimum a rocker bar is required if the floor has been removed on any uni-body type car with a cage. I would put rocker bars on both sides of the car. The dash bar size is different depending on how your a pillar bars are bent. If the a pillar bars are broken at the dash then the dash bar is 1 1/2". I the a pillar is continuous then the dash bar can be 1 1/4". I would make the dash bar continuous across the car and attach the mid plate tubing to it.
 
If you have access to someone who does tech inspections with your area sanctioning body, that's who I would ask. I took my car to a national event on the trailer & grabbed one of the tech inspectors with IHRA. We both had rule books & he was kind enough to go over everything with me. I kept copious notes & high lighted sections in the rule book he pointed out. After another year, I had everything in, welded up, belts in the car ready to race. Went to the divisional race, breezed through tech, got my ATI {annual tech inspection sticker} & am still racing that was almost 10 years ago.
 
Thank you for you guy's input.
I have been dissecting the "book" and I think I got it now. Biggest issue I see is my ladder bar cross member is way further forward than a 4 link would be and I won't upset its mount in the rocker.
My cage currently sits on a 12" x 12" plate linked to another 2x3 tube attached to the frame and rocker in the rear. I'm 6'4 and with the mid frame, engine back, and 3 pedals it looks to be my only option. I will fuse in a square tube to the rocker from there forward.
The frame to rocker diagonals will have to go to or my exhaust won't fit.
If it doesn't pass I'll add or sell the roller, by a shell and put a tube chassis under it.
 
Is the stock firewall in there or did you move it back?

When you are that tall, and the firewall is moved back its hard to get it all to fit, especially with a ladder bar. You just run out of room for everything.
 
no the firewall is gone. really there is nothing left on the car
The motor is mocked up about 12" back from stock and lowered. My crank height is about 13.5"
 
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