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Discussion Starter #1
I have a small obstacle to overcome. Hope someone can shed some light . I'm installing cage tubes and came across the rule [You can't cut into the Forward Cross Member/Foot Brace]. I had planned to notch the 2''x3'' tube to allow for 4" exhaust. But that's a no no I see by the rules. Last night i came up with this idea of turning the 2''x3'' tube on it's side (Or using a 2''x2'' tube if I can. Notching the end of the cross member 2"x1" so it can be welded to the side and top of the main 2"x3" frame rail. (see attached) This set-up would mean a 1" rise in the floorboard @ the cross brace but would give me the needed clearance for the exhaust. I may be able to weld the cross brace flush with the top of the main frame rail, but then it gets pretty tight for the exhaust. I'm sure I'm not the first to run into this? Is there a better way to do this and would this pass tech?? (25.4 Mild Steel Chassis) I'm open to ideas.

I plan to dump the exhaust through the rocker panel in front of the back cross brace, so that 1 isn't an issue. Thanks in advance for your input.
 

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Discussion Starter #2
I think I may have found the answer to my own question. Looks like I can substitute a 1 5/8" round for the 2''x3'' if I'm reading the SFI book right?
 

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As far as saftey goes, I would not want to lay the 2x3 on its side. The cage has to withstand a top impact to do any good at all. Laying on its side the 2x3 is much weaker structurally. Seems to me that 1 5/8 is a little small for a frame tie in as well. On my cage, I used 2x3x1/8 for the tie ins. I wanted something nice and strong to tie the cage to the frame. I had the same exhaust problem on my S-10 and ended up running it inside the frame. Problem is I had to cross to under the frame to get there. My "street" exhaust only has 2 1/2 inch clearance so it does not meet the rule book. I have a dump tube for racing already fabbed up.

There are three bars tieing in to that point and alot of force going through that tie in when the car is trying to flex under torque loads or in the unfortunate event of a crash.

Just something to think about...
 

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Discussion Starter #4
My plan is to run the rocker bar forward to intersect with the rear motor plate and build a cage around my feet with an "X" brace behind the firewall. This will serve as another support for the cage/body mount so I'll actually have 2 cross member/foot braces. Since my firewall is mostly cut away and it is a part time street car, I thought that would give me extra protection even tho it will mean a few extra pounds.
 

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That will help strengthen the tie in for sure. If you go with the tube tie in, I would add a short gussett from the outrigger to the frame. It adds alot of strength believe it or not. When I did the frame back and cage on my S-10 I was not at all happy with the rigidity of the rear frame. It had a good bit of flex when picking up on the frame. I added 1 inch gussets in my halo, main hoop, and front bars. It made a world of difference in the rigidity of the frame.

Chris
 
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