Do you have to box in cage mounts?

[VegasNick]

I had to make plates to tie the cage into the car. These are 1/4" steel. I could not fine anything that stated that they had to be boxed on the open side.

 

[cagedruss]

You have 4 points of contact to the chassis with what you have, you would gain one more if you boxed it in.

 

Do you have room for the seat if it is slid back?

[Ogren-Engineering]

 The BA cross section  that runs across the car should be the cage base mount point. Move it back 4 in and use the strong parts, not the floor. 

Edited April 12, 2018 by Ogren-Engineering

[VegasNick]

7 hours ago, cagedruss said:

You have 4 points of contact to the chassis with what you have, you would gain one more if you boxed it in.

 

Do you have room for the seat if it is slid back?

That is what I looked at originally was moving the cage back, but it sat it back too far. I looked at some other builds (much older NASCAR) and many of them used the same method. Not opposed to boxing it, just curious what the regulatory requirement was. 

[VegasNick]

1 hour ago, Ogren-Engineering said:

 The BA cross section  that runs across the car should be the cage base mount point. Move it back 4 in and use the strong parts, not the floor. 

I am a little late in the game for moving it back.  

[mender]

I would probably remove that 1/4" plate and use 1/8" plate along the sill, floor and kickup to form a strong pocket in that corner. I'd also use thinner material for your base plate, reduce the horizontal part that your hoop sits on and weld the base plate more in middle of the material in the reinforced pocket instead of the edge. That would distribute the load and give the surrounding material a chance to bend a bit instead of punching through.

 

Not a great picture but this is the idea:

 

If you just box in the front, you would have a "cookie cutter" on those inner edges with that 1/4" plate. And while you have the 1/4" plate out you can drop the hoop down and get a good 360 degree weld on your front stays.

Edited April 12, 2018 by mender

[CGDerian]

Boxing in allows you to lower the cage vertically so you can get a good full- circumference weld on the tubes attaching to the roll hoop and Halo bars...i.e. fit your 4-point cage and drop it down through holes you've cut in the floor to get access to weld tunes that are close to the underside of the roof. They are not required

 

I've also seen people slide a 1/8" plate between the bottom of the A and B pillar tubes and the floor, the weld the plate to the floor and tune to the plate, this was done after lowering the 4-point cage through holes in the floor and fully welding the tubes near the roof.