Roll Bar Mounts

Hey guys,

My old T-Bird was way too rusty to bother doing any chassis work on, so off it went to the junk yard. They even had a hard time chaining it down in the tie down holes.

So, I'm on to the Fairmont. It is real minty, no rust at all. What a nice change!!

My question is about the roll bar mounts. The NHRA book shows the 6x6 plates on the floor with the roll bar welded to that. John Bozzell posted pics of his Futura with 2x3 outriggers from the subframe to the rocker with the roll bar mounted to that. https://www.429-460.com/t5838p15-thunderbird-sub-frame-connectors-pics-added This looks way stronger, but will it pass tech? I've also seen outriggers at 90* like John's and I've seen them on a 45* angle, is the any advantage?

I am putting the thru-floor SFC in it in the next couple days but the insurance companies don't like to see roll bars/cages on street cars so I'm gonna wait to put the roll bar in till after its on the road. I just want to prep in the outriggers now while I'm welding on the floor.

Thanks for the info!!

Bill

On an 8.50 & slower NHRA/IHRA legal cage, and not a 8.49 & faster SFI legal cage/frame structure.......


The 6" x 6" x 1/8" weld plates are only to be used on OEM uni-body style cars because they don't have a "real" OEM frame to attach the 6 main cage structure "legs/feet" to (main hoop = 2, windshield bars = 2, rear main hoop supports = 2, using the minimum 1 5/8" x .083cm or .118 ms round tube). But an OEM uni-body style car doesn't need the 6x6 plates anywhere a tubular fabricated frame structure is placed (instead of a 6x6 plate) to weld any of the above mentioned cage legs/feet to (so any fabricated tubular structure like a ladder bar/4-link crossmember, or the rocker bars, or frame rails, or other fabricated crossmembers, or outriggers, or foot cross bars, or etc, etc, etc) as long as they meet the minimum tube OD & wall thickness size called for in the rule books. Also each weld plate (if used) doesn't have to stay a 6x6 square, they can be any shape as long as each plate has a total footprint of at least 36 square inches. The plates can be welded 100% only to the floor if you like. Or they can be bent/folded so most of the plate attaches to the floor with a lesser amount attaching to the inside of the rocker panel. Or they can be reversed so most of the plate attaches to the inside of the rocker panel with a lesser amount attaching to the floor.


On cars that have a real OEM frame (perimeter or otherwise) the 6x6 plates can't be used because the main cage legs-feet must be welded directly to the OEM frame, and/or to OEM or fabricated crossmembers, and/or to any needed fabricated outriggers. And any fabricated crossmember or fabricated outrigger where the cage legs-feet will be welded must meet the minimum tube OD & wall thickness size called for in the rule books.

According to the NHRA book the minimum tubing size for any fabricated frame structure that the 6 main cage legs-feet will be welded to is either......

(A) 1 5/8" x .083" cm or .118" ms round tubing.

(B) 2" x 2" x .058" ms and/or cm square tubing.

So on an 8.50 & slower uni-body car the main cage legs-feet can sit on any fabricated structure using the above minimum tubing sizes (or larger tubing sizes) instead of the 6x6 plates.

DILLIGASDAVE wrote:On an 8.50 & slower NHRA/IHRA legal cage, and not a 8.49 & faster SFI legal cage/frame structure.......


The 6" x 6" x 1/8" weld plates are only to be used on OEM uni-body style cars because they don't have a "real" OEM frame to attach the 6 main cage structure "legs/feet" to (main hoop = 2, windshield bars = 2, rear main hoop supports = 2, using the minimum 1 5/8" x .083cm or .118 ms round tube). But an OEM uni-body style car doesn't need the 6x6 plates anywhere a tubular fabricated frame structure is placed (instead of a 6x6 plate) to weld any of the above mentioned cage legs/feet to (so any fabricated tubular structure like a ladder bar/4-link crossmember, or the rocker bars, or frame rails, or other fabricated crossmembers, or outriggers, or foot cross bars, or etc, etc, etc) as long as they meet the minimum tube OD & wall thickness size called for in the rule books. Also each weld plate (if used) doesn't have to stay a 6x6 square, they can be any shape as long as each plate has a total footprint of at least 36 square inches. The plates can be welded 100% only to the floor if you like. Or they can be bent/folded so most of the plate attaches to the floor with a lesser amount attaching to the inside of the rocker panel. Or they can be reversed so most of the plate attaches to the inside of the rocker panel with a lesser amount attaching to the floor.


On cars that have a real OEM frame (perimeter or otherwise) the 6x6 plates can't be used because the main cage legs-feet must be welded directly to the OEM frame, and/or to OEM or fabricated crossmembers, and/or to any needed fabricated outriggers. And any fabricated crossmember or fabricated outrigger where the cage legs-feet will be welded must meet the minimum tube OD & wall thickness size called for in the rule books.

According to the NHRA book the minimum tubing size for any fabricated frame structure that the 6 main cage legs-feet will be welded to is either......

(A) 1 5/8" x .083" cm or .118" ms round tubing.

(B) 2" x 2" x .058" ms and/or cm square tubing.

So on an 8.50 & slower uni-body car the main cage legs-feet can sit on any fabricated structure using the above minimum tubing sizes (or larger tubing sizes) instead of the 6x6 plates.

Thanks a bunch Dave, very thorough as usual!!

Bill

Yep.  It'll pass tech just fine.  My Futura was certified back in 1995 and will pass again with flying colors next year.  My Mustang is the same way also.

IMO, it's the only way to go.  The cage needs to push the whole subframe out of the car rather than a 6x6 plate.  Way stronger IMO...

Also, if I was to do it all over again I'd make the piece long enough to slide into the rear subframe and "catch" that lower control arm bolt. Should beef up the rear torque box a bunch.

jbozzelle wrote:Yep.  It'll pass tech just fine.  My Futura was certified back in 1995 and will pass again with flying colors next year.  My Mustang is the same way also.

IMO, it's the only way to go.  The cage needs to push the whole subframe out of the car rather than a 6x6 plate.  Way stronger IMO...

Also, if I was to do it all over again I'd make the piece long enough to slide into the rear subframe and "catch" that lower control arm bolt.  Should beef up the rear torque box a bunch.

Great, thanks John!! It sure looks much stronger than the 6x6 plates. I'm going to try and get back to the control arm mount too. I've been under it today wire wheeling all the seam sealer and stuff off so I can weld the boxes up, then I will start on the SFC's.

I've never had a project this clean to work with, I'm pretty excited about getting it built right and see what this engine can do with some traction!!

Thanks again for the input guys!!

Bill