OxTheGreat

Im welding in my MWC roll cage this weekend and part of the job will be removing the cowl in front of the windshield. Does anyone have pictures or advice of what is needed to get the bay bars into car and welded into its appropriate spot? there arent many pics out there of how they are routed or where they get welded. I assume it welds to the dash bar or the hoop that rides down the A pillar to the floor. This is a time sensitive subject so i may spread this post over varies threads to get as many eyes on.

thanks in advance

Ox

pdxmotorhead

On a car with front strut towers,, the through the firewall trusses usually start just below or behind the dash penetrate the firewall and tie to a plate on the strut tower.. te trick is to use a laser and aim at the firewall from the rollbar, find a screw(s) you can measure from and drill a pinhole, hopefully the laser it pointed at the right spot on the strut tower.

On a non strut car you tie from as high as you can get on the rollbar through the firewall to the chassis just ahead of the suspension. I've used the holes for the dash vents by the doors for the hole before. Or you go below the padded dash through to get a similar route..

I'd google lots of pictures, and the laser pointer taped to a magnet works pretty well for eyeballing stuff.. Triangles are strong rectangles are week, download the SCCA rulebook (GCR/General competition rules and it has some good cage pics. The GT cages are closest to what drag cars use.. If your going to drive a caged car on the street, make sure you analyze head impact points, in a roll, in a head on and in a t-Bone. Make sure any bar no matter how weird has FIA hard padding on it.. It will protect you and your passengers better than the spongy stuff.. In a dual purpose car you want the Halo tight to the roof, and the roll bar main hoop behind the plane of the headrest. The plates that het cage gets wellded to need to be different sizes on the inside and outside of the chassis, if they match they become a sheer and will slice the body on impact.

OxTheGreat

it is on a 4th gen Firebird that has the strut towers. i see guys ride the top of the strut tower a few inches from the fender mounting lip. just no details on the placement aftward through the firewall and dash

pdxmotorhead

Ye that part is a "eyeball " skill, but if you play with the laser from both sides and pay attention to the identifiable bolt screws and stuff on the firewall, FWIW I've done a dozen or so cages and I have never got that hole right/perfect on the first try.,, its also VERY unlikely that bar is straight.. Mist of them have some curve to weave around the dash structure or some bit that's in the way. One thing I've done in the past is they sell a round gadget with a rubber grommet in it the metal part is about 6" in diameter, you buy it for the size tube your using, it gets pop riveted in after you weld the bar in.. Makes it looke like everything is done on purpose..

OxTheGreat

Noted. my welder has done many cages in his time but im trying to get a head start on information to prevent possible work stops since he is allowing me and a couple buddies to part take in the installation. The cage is a pre-notched pre-fit MWC cage.........so fingers crossed

pdxmotorhead

Well pre-cuts usually fit loose in the car, so it should install fairly easy. I've replaced/lengthened the knee tube and the behind the seat tube (where the belts attach) on a few, to spread the cage out tighter to the chassis. If the rules allow I gusset the bars to the upper and lower pillars.. Will raise the torsional rigidity about 1000 lbs.. (If that's desired) Good luck with the project, cages are always fun.